Showing papers in "Journal of Medical Screening in 2005"
TL;DR: Both the sensitivity, specificity and positive predictive value of VIA and VILI in detecting CIN 2 or CIN 3 could be significantly improved depending on the combination with Pap smear or HCII (sensitivity up to 100.0% and specificity up to 99.8%).
Abstract: Objectives: To assess the performance indicators of visual inspection with acetic acid (VIA) and visual inspection with Lugol's iodine (VILI) in four Latin American centres participating in the ongoing Latin AMerican Screening (LAMS) study, in settings with moderate incidence of cervical disease and with poorly to moderately well-organized cervical cancer screening.Setting: Three Brazilian centres (Sao Paulo, Campinas and Porto Alegre) and one Argentine centre (Buenos Aires) recruited a total of 11,834 healthy women to undergo VIA, VILI, conventional Pap smear and Hybrid Capture II (HCII).Methods: Women who had a positive result from any of these tests were subjected to colposcopy and biopsies (if necessary), and women with high-grade cervical intraepithelial neoplasia (CIN) were properly treated. To control for verification bias, 5% of women with normal tests were referred for colposcopy, as were 20% of HCII-negative women.Results: Data on VIA (n=11,834), VILI (n=2994), conventional Pap smear (n=10,138) ...
146 citations
TL;DR: There is a need to address the issue of screening for disease, with an emphasis on providing accurate and practical information relevant to all countries, from a Consultation Group meeting held at WHO headquarters in Geneva.
Abstract: Screening people for serious diseases is receiving increasing attention as studies demonstrate the potential benefits of early detection and early intervention in preventing morbidity and mortality. Screening tests are available for some of the most important noncommunicable diseases, including cardiovascular disease, type 2 diabetes and several site-specific cancers. However, screening guidelines for cardiovascular disease, cancers and diabetes vary within and between countries because many national and international organizations are developing their own guidelines. There is a need to address the issue of screening for disease, with an emphasis on providing accurate and practical information relevant to all countries. This report arose from a Consultation Group meeting held at WHO headquarters in Geneva. It presents an examination of the principles of screening with an emphasis on noncommunicable disease prevention and control policy. Screening people for serious diseases is receiving increasing attention as studies demonstrate the potential benefits of early detection and early intervention in preventing morbidity and mortality. Screening tests are available for some of the most important noncommunicable diseases, including cardiovascular disease, type 2 diabetes and several site-specific cancers. However, screening guidelines for cardiovascular disease, cancers and diabetes vary within and between countries because many national and international organizations are developing their own guidelines. There is a need to address the issue of screening for disease, with an emphasis on providing accurate and practical information relevant to all countries. This report arose from a Consultation Group meeting held at WHO headquarters in Geneva. It presents an examination of the principles of screening with an emphasis on noncommunicable disease prevention and control policy.
119 citations
TL;DR: Contrary to expectations, men were more likely than women to attend FS screening, but additional research is needed to understand the key aspects of FS screening that will maximize screening uptake in men and women.
Abstract: Objectives: To assess the demographic and psychological mediators of gender differences in uptake of flexible sigmoidoscopy (FS) screening for colorectal cancer.Setting: A subsample (n=5462) from a...
111 citations
TL;DR: Compliance is more likely with the immunochemical than the guaiac test, independent of the provider, and Guaiac tests show a higher variability of the results among centres.
Abstract: Introduction: We conducted a cluster-randomized trial aimed at assessing the effect of the type of faecal occult blood, guaiac or immunochemical test on screening compliance.Methods: We sampled 130 general practitioners (GPs) who consented to participate in the trial. We randomly allocated half of them to the guaiac (Hemo-Fec) and half to the immunochemical test (OC-Hemodia). We sampled 2/10 of the GPs' 50–75-year-old patients (n=7332) and randomly divided this population into half. One half was invited to be screened at the GP's office and the other to the nearest gastroenterology ward. The principal outcome was the percentage of returned tests.Results: The immunochemical test had a compliance of 35.8% and the guaiac of 30.4% (relative risk [RR] 1.20; 95% confidence interval [CI] 1.02–1.44). The difference was mostly due to a higher probability of returning the sample: 93.8% and 88.6% for immunochemical and guaiac, respectively (RR 1.06; 95% CI 1.02–1.10). The guaiac test had a higher prevalence of posit...
97 citations
TL;DR: Women participating in cervical screening need high-quality information about HPV and its role in cervical cancer prior to screening rather than afterwards, when they face an abnormal result.
Abstract: Objective: The role of human papillomavirus (HPV) in cervical cancer and developments in medical technology to prevent cervical cancer has changed information needs for women participating in cervi...
85 citations
TL;DR: Efforts to improve mammographic screening in the USA should target lowering the recall rate without reducing the cancer detection rate.
Abstract: To compare the performance of screening mammography in the USA and the UK, a consecutive sample of screening mammograms was obtained in women aged 50 and older from 1996 to 1999 who participated in the Breast Cancer Surveillance Consortium in the USA (n=978,591) and the National Health Service Breast Cancer Screening Program in the UK (n=3.94 million), including 6943 diagnosed with breast cancer within 12 months of screening. Recall rates were defined as the percentage of screening mammograms with a recommendation for further evaluation including diagnostic mammography, ultrasound, clinical examination or biopsy, and cancer detection rates including invasive cancer and ductal carcinoma in situ diagnosed within 12 months of a screening mammogram. All results were stratified by whether examinations were first or subsequent and adjusted to a standard age distribution. Among women who underwent a first screening mammogram, 13.3% of women in the USA versus 7.2% of women in the UK were recalled for further eval...
79 citations
TL;DR: The implementation of colorectal cancer screening in Finland in this way meets the criteria for a randomized controlled trial and the requirements for a public health programme and may set an example for the introduction of all national screening programmes.
Abstract: Colorectal cancer mortality can be reduced by repeated faecal occult blood (FOB) testing followed by colonoscopy for test positives. The object of this report is to describe how to launch a new screening programme in such a way that its effectiveness can be reliably evaluated. The programme is based on gradual expansion over time with individual-level randomization into screening or control arms among a target population aged 60-69 years in Finland. The target population will be sampled from the population register for invitees and controls by municipality and by birth cohort. The non-invited controls will gradually be screened only after the six-year implementation period. After 10 years, the programme covers the entire target population. The effects of screening will be evaluated, comparing the incidence of and mortality from colorectal cancer in those invited to screening with controls. The primary screening test is a biannual guaiac-based FOB test with three test cards for consecutive samples. In September-December 2004, around 5000 test-kits were sent to 22 piloting municipalities. In 2005, the programme expands both among municipalities and the target population, resulting in nearly 20,000 individual requests. The implementation of colorectal cancer screening in Finland in this way meets the criteria for a randomized controlled trial and the requirements for a public health programme. It allows unbiased research data to be collected while introducing the programme and may set an example for the introduction of all national screening programmes.
71 citations
TL;DR: Second reading is effective in detecting a limited number of additional cancer cases, and since cancer detection at second reading seems cost-effective the procedure is recommendable in routine practice.
Abstract: Objective: To assess double reading effectiveness in mammography screening.Design: Retrospective study of 177,631 consecutive mammograms double read during 1998–2003.Setting: The Florence screening programme, involving 11 trained radiologists. Abnormalities reported by at least one reader prompted assessment.Results: The referral rate was 2.89% for the first reader, 3.15% for the second reader, and 3.59% for either reader. Of 713 total cancers detected, 43 were suspected only by the second reader (6.4% relative, 0.024% increase in absolute detection rate) and had a lower stage compared to the first reader (pTis–pT1b = 65.7 versus 52.0%): 41 were reviewed and classified (error type) as 'minimal sign' in six, and 'screening error' in 35 cases, or as BI-RADS 3 in one, 4a in 20, 4b in 13, and 4c in three cases. The second reading cost was €2.70 per woman examined, or €11,168 per additional cancer detected (versus €11,585 at a single reading).Discussion: Second reading is effective in detecting a limited numbe...
68 citations
TL;DR: A number of important issues concerning childhood hearing loss and its management remain unresolved: the burden of late-onset and temporary childhood hearing losses, the most effective approaches to intervention and management, the case for screening for mild and/or unilateral hearing loss, and the role of the School entry screen.
Abstract: Until recently, screening for childhood hearing loss in the UK was based on two universal (i.e. whole population) screens: the infant distraction test screen at age eight months and the school entry hearing screen at age four to five years. Evidence reviewed in the 1990s indicated that the infant distraction test screen was seriously underperforming, but that (based on technology that had become available in the 1980s and 1990s) universal newborn hearing screening could be efficacious. At the same time, evidence was emerging on the importance and value of very early identification and intervention for permanent congenital childhood hearing loss. This led to the decision to implement a national newborn hearing screening programme (NHSP) in England and to phase out the distraction test at eight months. The initial implementation of the programme will be completed in 2005, and we summarize the evidence on the effectiveness of the first phase of the programme here. A number of important issues concerning childhood hearing loss and its management remain unresolved: the burden of late-onset and temporary childhood hearing losses, the most effective approaches to intervention and management, the case for screening for mild and/or unilateral hearing loss, and the role of the School entry screen. Some of the current research efforts to address these are outlined.
62 citations
TL;DR: It is intuitively thought that combining moderately strong risk factors can substantially improve screening performance, as most cardiovascular risk factors have a relatively modest screening performance.
Abstract: Objective: To determine the quantitative effect on overall screening performance (detection rate for a given false-positive rate) of using several moderately strong, independent risk factors in combination as screening markers.Setting: Theoretical statistical analysis.Methods: For the purposes of this analysis, it was assumed that all risk factors were independent, had Gaussian distributions with the same standard deviation in affected and unaffected individuals and had the same screening performance. We determined the overall screening performance associated with using an increasing number of risk factors together, with each risk factor having a detection rate of 10%, 15% or 20% for a 5% false-positive rate. The overall screening performance was estimated as the detection rate for a 5% false-positive rate.Results: Combining the risk factors increased the screening performance, but the gain in detection at a constant false-positive rate was relatively modest and diminished with the addition of each risk f...
62 citations
TL;DR: This review examines the published literature to assess the morbidity and mortality attributable to neonatal GBS infection, quantify the screening performance of the two alternative modes of screening, review the evidence on the efficacy of the vaccine, and estimate the numbers of deaths and cases of serious disability that each strategy in turn might prevent in the UK.
Abstract: Streptococcus agalactiae, or Lancefield group B streptococcus (GBS), is the most frequent cause of serious bacterial sepsis, including neonatal meningitis, in UK neonates. Early-onset neonatal GBS infection, but not late-onset, can be prevented by screening to identify high-risk pregnancies and administering penicillin during delivery. A vaccine has been developed as an alternative means of prevention but it is awaiting a randomized trial before being available for general use. In this review we examine the published literature to assess the morbidity and mortality attributable to neonatal GBS infection, quantify the screening performance of the two alternative modes of screening (microbiological and risk factor based), review the evidence on the efficacy of the vaccine, and estimate the numbers of deaths and cases of serious disability that each strategy in turn might prevent in the UK, in order to assess the most effective means of prevention for the UK.
TL;DR: It is shown that colonoscopy with sedation is a very comfortable procedure and both procedures are well tolerated and suitable for colorectal cancer screening.
Abstract: Objectives: To study an individual's experience of either flexible sigmoidoscopy (FS) or colonoscopy in a colorectal cancer prevention programme.Methods: Consecutive individuals in a Bowel Cancer Prevention Programme, who had either an unsedated FS or a colonoscopy with sedation, participated in a prospective cross-sectional questionnaire-based study.Results: A total of 447 responses were obtained for 256 colonoscopies and 191 FSs (200 men [45%] and 247 women [55%]). The overall experience of colonoscopy was more comfortable than FS (75% versus 18%; P<0.001). Embarrassment was low for both procedures (8%). There was no pain associated with colonoscopy and most individuals had a pain score of less than 3 (11-point scale) for FS: 72% of men, 55% of women (P<0.001). Most individuals did not have a gender preference for the endoscopist. For colonoscopy, the worst part of the procedure was the preparation (78%) and for FS the preparation and the procedure ranked equally worst (30%).Conclusions: We have shown t...
TL;DR: Neither a telephone call from a nurse nor a letter from a celebrity to encourage attendance for cervical screening were effective or cost-effective in women with a prolonged history of non-participation in the screening programme.
Abstract: Objective: To compare the effectiveness and cost-effectiveness of three methods of inviting women with a long history of non-attendance to undergo cervical screening.Methods: Randomized controlled trial and cost-effectiveness analysis. In all, 1140 women were identified from routine NHS screening records as having no smear for at least 15 years and randomly allocated to receive a telephone call from a nurse, a letter from a well-known celebrity (Claire Rayner) or letter from the local NHS Cervical Screening Commissioner. Uptake of screening was measured using routine data and attributed to interventions if occurring within three months. Uptake was compared with a control group. Costs of carrying out the interventions were noted from the perspective of the NHS and cost-effectiveness, as cost per additional attender, calculated.Results: Uptake following all interventions was low: telephone call (1.4, 95% confidence interval [CI] 0.38–3.6%); celebrity letter (1.8, 95% CI 0.57–4.0%); commissioner letter (4.6,...
TL;DR: The new estimates indicate that screening detectable phase is longer than that found in previous mammography trials/programmes, but also that the sensitivity of the screening test is lower, which indicates that the NBCSP detects more cancer cases than most previous trials/ programs.
Abstract: Objective: To assess if new screening techniques, increased use of hormone replacement therapy, or the transition from breast cancer screening trials to large scale screening programmes may influence the average time in preclinical screening detectable phase (mean sojourn time [MST]) or screening test sensitivity (STS).Setting: Screening and interval data for 395,188 women participating in the Norwegian Breast Cancer Screening Programme (NBCSP).Methods: Weighted non-linear least-square regression estimates using a tree step Markov chain model, and a sensitivity analysis of the possible impact by opportunistic screening between ordinary breast cancer screening rounds.Results: MST was estimated to 6.1 (95% confidence interval [CI] 5.1–7.0) years for women aged 50–59 years, and 7.9 (95% CI 6.0–7.9) years for those aged 60–69 years. Correspondingly, STS was estimated to 58% (95% CI 52–64 %) and 73 % (67–78 %), respectively. Simulations revealed that opportunistic screening may give a moderate estimation bias ...
TL;DR: A review of the available literature shows that permanent childhood hearing loss is a significant health condition and its detection through screening with oto-acoustic emissions and/or auditory brainstem response is feasible in the target population, and newborn hearing screening is a potential early detection strategy for permanent childhood Hearing loss in Nigeria.
Abstract: Newborn hearing screening has been recognized as an essential component of public health care in early childhood in developed countries. However, such screening is yet to be widely embraced in the developing world. The new national health policy in Nigeria seeks, for the first time, to reduce the impact of permanent hearing loss on early childhood development through early detection and timely intervention services. The aim of this paper is to ascertain if newborn hearing screening satisfies the conventional criteria for a screening programme as an early detection strategy in this developing country. A review of the available literature shows that permanent childhood hearing loss is a significant health condition and its detection through screening with oto-acoustic emissions and/or auditory brainstem response is feasible in the target population. Amplification with hearing aids is an effective and preferred option for early intervention by parents. The risk of maternal anxiety from potential false-positives or the psychological cost of false assurance from false-negatives is unlikely to outweigh the benefit of screening. Newborn hearing screening is therefore a potential early detection strategy for permanent childhood hearing loss in Nigeria.
TL;DR: In neonates with low and very low birth weight, normal TSH levels measured between the third and sixth day of life do not exclude thyroid dysfunction, but a repeat TSH measurement after the fourth week of life identifies the false-negative results.
Abstract: Objectives Thyroid-stimulating hormone (TSH), normally a reliable screening test for congenital hypothyroidism (CH), may fail to detect cases among infants who have low and very low birth weight. The purpose of this study was to identify neonates with false-negative screening results. Setting A province in Poland in which 3854 neonates had body weight p2500 g, between 1999 and 2001. Methods TSH levels in blood on filter paper were measured in all neonates between the third and sixth days after birth, but were repeated in low and very low birth weight infants after four weeks of age. Results The repeat test showed TSH levels X10 mIU/L in 19 of the 3854 low birth weight neonates. The final diagnosis in these neonates was permanent CH in two, transient CH in five, possible compensated CH in six and transient high TSH in six. Of the 19, 16 (84%) required iodine and/or thyroxine replacement therapy. Conclusions In neonates with low and very low birth weight, normal TSH levels measured between the third and sixth day of life do not exclude thyroid dysfunction, but a repeat TSH measurement after the fourth week of life identifies the false-negative results. In our data, the prevalence of primary and secondary hypothyroidism (both permanent and transient) was about 0.5%.
TL;DR: Both PGMI and EAR have poor reliability and validity in evaluating mammogram quality and EAR is not a suitable alternative to PGMI, which must be improved if it is to be useful.
Abstract: Objective: To compare the reliability and validity of two classification systems used to evaluate the quality of mammograms: PGMI ('perfect', 'good', 'moderate' and 'inadequate') and EAR ('excellen...
TL;DR: SCDs should be considered a major public health problem in Ouagadougou and a neonatal screening programme should be implemented, but to be effective it requires strategies adapted to the local situation.
Abstract: Objectives: To determine the incidence of sickle cell disorders (SCDs) and the feasibility of a neonatal screening programme in Ouagadougou.Methods: During 2000, 2003 and 2004, 2341 cord blood samples obtained in five maternity hospitals in Ouagadougou were screened for SCDs using an isoelectric focusing technique. The feasibility of a neonatal screening programme was evaluated.Results: The incidence of SCD was 1:57; 14 neonates were homozygous for haemoglobin (Hb)S and 27 were compound heterozygotes for HbSC. Thirty-two neonates were homozygous for HbC. The incidence of the HbC trait was 1:6; incidence of the HbS trait was 1:14. A centralized laboratory for neonatal screening of SCDs was established.Conclusions: SCDs should be considered a major public health problem in Ouagadougou. A neonatal screening programme should be implemented, but to be effective it requires strategies adapted to the local situation.
TL;DR: Routine neonatal screening in areas with a high prevalence of G6PD in Saudi Arabia is justifiable, and the prevalence is relatively high in Yanbu.
Abstract: Objective: To determine the prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency in the population tested, and to evaluate the prevalence of neonatal jaundice in newborns with G6PD deficiency.Methods: Cord blood of all babies born between October 1996 and October 1998 at the Royal Commission Medical Center in Yanbu, Saudi Arabia, was screened for G6PD deficiency by fluorescent spot test. The results of screening of cord blood samples were reported to the physician in charge, and also placed on the files of the babies and their mothers. These babies were observed for 72 h and discharged if no jaundice developed.Results: During this two-year period, 2505 neonatal cord blood samples from 1278 boys and 1227 girls were screened for G6PD. There were 50 positive results for G6PD deficiency (39 boys and 11 girls), and the prevalence was estimated to be around 2%. The sex-specific prevalence for boys was 3.05%, and for girls 0.9%. Male to female ratio was 3:1. Neonatal jaundice developed in six (12%) ...
TL;DR: Pregnant women in the UK discussed 'information' and 'consent' as two separate issues, thus challenging assumptions around the term informed consent.
Abstract: Objectives: To explore the attitudes of a sample of pregnant women in the UK towards informed consent for antenatal thalassaemia carrier testing and perceived pre-test information needs for such testing. Setting: The study was conducted in two cities in the North of England, where participants were recruited via Midwifery and Genetic services. Method: In all, 110 Pakistani women tested and not found to be thalassaemia carriers completed a questionnaire, 14 of whom were also interviewed. Thirty-six women identified as carriers or possible carriers completed a questionnaire and were interviewed. The questionnaires assessed whether women were aware that they had been tested for thalassaemia carrier status, whether they were asked for their consent for such testing, and their pre-test information preferences. The interviews explored women's beliefs about 'informed consent' in more depth. Results: Women had received little or no pre-test information and said that they would have preferred to be informed that they were being tested, but they did not expect, or express a desire, to be asked for their informed consent. Conclusion: While information was important to women, consenting was not. Overall, women discussed 'information' and 'consent' as two separate issues, thus challenging assumptions around the term informed consent. Women wanted pre-test information because they wanted to know more about the tests that they would be having, not to use it to make decisions about whether to have the tests.
TL;DR: Arbitration of discordant double reading would substantially reduce referral rates with a limited reduction in cancer detection rate, and may be recommended as a routine procedure.
Abstract: Objective: To asses the effectiveness of arbitration of discordant double readings in mammography screening. Design: A retrospective study of 1217 consecutive arbitrations. Setting: A subset of discordant double readings from the Florence screening programme underwent arbitration by a third reader. Results: Positive arbitration of 1217 discordant double readings prompted assessment in 476 cases (39.2%), detecting 30 cancers (6.3%). Of 741 negative arbitrations (60.8%), 311 have been followed up thus far, and two cancers (0.64%) occurred in the site previously suspected at one of the two independent readings. Arbitration had a sensitivity of 86.3% and a negative predictive value of 99.3%. Arbitration reduced the overall referral rates from 3.82% to 2.59% (relative decrease 32.1%). Due to false-negative arbitration, cancers detected per 1000 women screened would decrease from 4.58 to 4.50 (relative decrease 1.7%). For every cancer missed due to false-negative arbitration, 151 unnecessary recalls and h21,248 would have been saved, whereas the saved cost per screened woman due to arbitration was h1.72. Discussion: Arbitration of discordant double reading would substantially reduce referral rates with a limited reduction in cancer detection rate, and may be recommended as a routine procedure. Greater benefit from arbitration might be expected in the presence of high referral rates at independent double reading, a common scenario in a newly implemented service screening.
TL;DR: In this paper, the authors assessed the extent to which different levels and patterns of participation affect cost effectiveness, using decision modelling of three colorectal cancer screening with FOBT scenarios, and estimated the incremental cost-effectiveness (value for money) ratios for each scenario.
Abstract: Background: In many countries high participation is an explicit target in screening programmes. The desire for high participation often appears to drive screening policy, although it is increasingly recognized that encouraging high participation may impinge upon the rights of an individual to make an informed choice. One argument offered in support of high participation is that it improves the cost- effectiveness of screening. This is questionable on theoretical grounds, and empirically there are conflicting results. Two recent cost-effectiveness models of faecal occult blood test (FOBT) screening for colorectal cancer (CRC) showed that cost-effectiveness was improved, another showed that cost- effectiveness was worsened and a fourth indicated that cost-effectiveness was unaffected by increasing the participation rate. Methods: We assessed the extent to which different levels and patterns of participation affect cost- effectiveness, using decision modelling of three CRC screening with FOBT scenarios. We estimate the incremental cost-effectiveness (value for money) ratios for each scenario. Results: The way in which participation is modelled, particularly assumptions made about the subsequent screening behaviour of non-participants ('if' and 'when' a non-participant attends for subsequent screening), affects the cost-effectiveness estimates for FOBT screening programmes. 100% participation in all screening rounds gives a cost per life year saved (LYS) of US$9705. Cost- effectiveness is worst when people who do not take part in one screening round (initial or subsequent) never take part in any future rounds of screening. Under this scenario, a participation rate of 20% in second and subsequent rounds gives a cost per LYS of US$29,500. Under more realistic assumptions, for example the attendance of even a small proportion of non-participants in subsequent rounds, cost- effectiveness is more favourable and similar to that achieved for full participation: the scenario with a random participation rate of 20% in second and subsequent rounds for both participants and non- participants has a cost per LYS of US$11,270. Conclusions: Contrary to a commonly held view, high participation in screening programmes is not necessary to achieve cost-effectiveness. Setting high target participation rates in screening programmes does not guarantee cost-effectiveness and may in certain circumstances reduce the cost-effectiveness.
TL;DR: It is useful to check whether a Gaussian approximation for the distribution of risk estimates based on a screening marker is valid, and if the value of the marker level at which risk reversal occurs lies within the set truncation limits, these may need to be reset, and aGaussian model may be inappropriate to illustrate the risk distributions.
Abstract: OBJECTIVE The screening performance of tests involving multiple markers is usually presented visually as two Gaussian relative frequency distributions of risk, one curve relating to affected and the other to unaffected individuals. If the distribution of the underlying screening markers is approximately Gaussian, risk estimates based on the same markers will usually also be approximately Gaussian. However, this approximation sometimes fails. Here we examine the circumstances when this occurs. SETTING A theoretical statistical analysis. METHODS Hypothetical log Gaussian relative distributions of affected and unaffected individuals were generated for three antenatal screening markers for Down's syndrome. Log likelihood ratios were calculated for each marker value and plots of the relative frequency distributions were compared with plots of Gaussian distributions based on the means and standard deviations of these log likelihood ratios. RESULTS When the standard deviations of the distributions of a perfectly Gaussian screening marker are similar in affected and unaffected individuals, the distributions of risk estimates are also approximately Gaussian. If the standard deviations differ materially, incorrectly assuming that the distributions of the risk estimates are Gaussian creates a graphical anomaly in which the distributions of risk in affected and unaffected individuals plotted on a continuous risk scale intersect in two places. This is theoretically impossible. Plotting the risk distributions empirically reveals that all individuals have an estimated risk above a specified value. For individuals with more extreme marker values, the risk estimates reverse and increase instead of continuing to decrease. CONCLUSION It is useful to check whether a Gaussian approximation for the distribution of risk estimates based on a screening marker is valid. If the value of the marker level at which risk reversal occurs lies within the set truncation limits, these may need to be reset, and a Gaussian model may be inappropriate to illustrate the risk distributions.
TL;DR: Estimation of interval cancer rates in four population-based mammography screening programmes in four countries with different health-care environments, different access to cancer registry data, and different age group women invited found rates were quite similar between three of the four centres.
Abstract: Objectives: The purpose of the present study was to estimate the interval cancer (IC) rates in four population-based mammography screening programmes in four countries with different health-care environments, different access to cancer registry data, and different age groups of women invited. Setting: The screening programmes in Coimbra (Portugal), Dublin (Ireland), Stockholm (Sweden), and Turin (Italy) participated in the study. Methods: All cancer cases were searched for in cancer registries. IC rates and other outcome measures from the screening programmes were estimated and compared between the centres. Poisson regression model was used to estimate the proportional incidence based on IC rate in relation to expected total breast cancer incidence rate in the absence of screening. Results: There was a more than tenfold difference in the number of invited women at the first round between the involved centres. The IC rates varied between 4.3 and 23.8 per 10,000 women screened. The levels of IC rates in relation to the estimated background incidence varied from 0.35 up to 0.46 depending on age groups involved in the programme, but did not differ significantly between three of the four involved centres. Conclusions: IC rates were quite similar between three of the four centres despite the differences in target population, invited ages, length of building-up of the programmes and different health-care organizations. Different access to complete cancer registry data is likely to explain the lower IC rates in the fourth centre. Objectives: The purpose of the present study was to estimate the interval cancer (IC) rates in four population-based mammography screening programmes in four countries with different health-care environments, different access to cancer registry data, and different age groups of women invited. Setting: The screening programmes in Coimbra (Portugal), Dublin (Ireland), Stockholm (Sweden), and Turin (Italy) participated in the study. Methods: All cancer cases were searched for in cancer registries. IC rates and other outcome measures from the screening programmes were estimated and compared between the centres. Poisson regression model was used to estimate the proportional incidence based on IC rate in relation to expected total breast cancer incidence rate in the absence of screening. Results: There was a more than tenfold difference in the number of invited women at the first round between the involved centres. The IC rates varied between 4.3 and 23.8 per 10,000 women screened. The levels of IC rates in relation to the estimated background incidence varied from 0.35 up to 0.46 depending on age groups involved in the programme, but did not differ significantly between three of the four involved centres. Conclusions: IC rates were quite similar between three of the four centres despite the differences in target population, invited ages, length of building-up of the programmes and different health-care organizations. Different access to complete cancer registry data is likely to explain the lower IC rates in the fourth centre.
TL;DR: Examples of approaches to quantification of overdiagnosis, evaluation of service screening outside the research setting, and use of screening data to investigate tumour biology and natural history are described.
Abstract: Randomized trials of mammography have demonstrated the efficacy of mammographic screening for breast cancer in terms of preventing deaths, but various issues of particular interest remain, including: quantification of overdiagnosis; evaluation of service screening outside the research setting; absolute benefit in terms of number needed to screen per life saved; which types of tumours benefit most from early detection; use of screening data to investigate tumour biology and natural history. This paper describes examples of approaches to the above issues, along with some important results.
TL;DR: The aim of the study was to empirically assess the acceptable levels of process indicators as described in the European Community Guidelines using materials from the mammography service screening programmes, and most, but notall, of these process indicators met the desirable reference values of the European community.
Abstract: The aim of the study was to empirically assess the acceptable levels of process indicators as described in the European Community Guidelines using materials from the mammography service screening programmes. The Finnish programme was evaluated for effectiveness with a prior estimate of 0.74 for RR in Finland and 0.81 in Helsinki. Hence, the Finnish programme was likely to be somewhat less effective in terms of reduction in mortality than implied on the basis of early randomized trials, but probably approaching the same level of effectiveness. Finland therefore provides background data on the applicability of the process indicators that are indicators of performance and surrogates for effectiveness. The performance data on 10 Finnish screening centres at subsequent screens were used. These centres invited 687,000 women aged 50-64 years in 1991-2000. The mean compliance was 93% and the corresponding recall rate was 2.3%. The benign to malignant biopsy ratio was 0.43:1. The average breast cancer detection rate was 0.36%, 2.1 compared with the background incidence. The proportion of screen-detected stage II+ cancers was 26%. Most, but not all, of these process indicators met the desirable reference values of the European Community. The specific criteria of the European Community on stage distribution, rates of screen-detected cancers by stage and detection rate to background incidence may need reconsideration.
TL;DR: Comparison of the effects of receipt of different results showed no significant differences in maternal anxiety, worry and certainty between the two tests, suggesting that newborn hearing screening does not have a more negative emotional impact than the HVDT.
Abstract: Background: Newborn hearing screening is currently replacing the health visitor distraction test (HVDT) conducted at eight months. Our previous research indicates that recall for further tests following newborn hearing screening can have a negative impact on the emotional well being of mothers, but it is not known if this is greater than that caused by recall following the distraction test.
Objective: To compare the impact on maternal anxiety and satisfaction of recall following newborn hearing screening and the HVDT.
Methods: Four groups participated: 27 mothers of babies receiving a satisfactory result and 21 mothers of babies recalled after the HVDT 26 mothers of babies receiving a satisfactory result and 16 mothers of babies recalled after newborn hearing screening. Questionnaires assessing maternal anxiety, worry and certainty about the babies' hearing, satisfaction with and attitudes towards the screening test were sent to mothers three weeks and six months following screening.
Results: Comparison of the effects of receipt of different results showed no significant differences in maternal anxiety, worry and certainty between the two tests. Those mothers whose babies had a newborn hearing screening test were significantly more satisfied, regardless of the result received. Those who received a satisfactory result on the newborn hearing screening programme also had more positive attitudes towards that screening test than those receiving a satisfactory result following the HVDT.
Conclusion: These results suggest that newborn hearing screening does not have a more negative emotional impact than the HVDT.
TL;DR: Multiple consecutive negative pap smears was not associated with reduced risk of invasive cervical cancer in women with no history of cytological abnormality, as well as in women without a history of cervical therapeutic procedure.
Abstract: Objective: To determine the relationship between the number of initial negative Pap smears and risk of subsequent cervical cancer.Design: A cohort study was conducted using data from the British Columbia Cervical Cancer Screening Program and British Columbia CancerRegistry. The analysis used a random sample (1%) of women aged 20–69 with Pap smears and all cases of invasive cervical cancer diagnosed between 1994 and 1999. Each negative screen defined the beginning of a screening interval and intervals longer than five years were truncated. Thefollowing variables were created for each interval: age at the beginning of the interval, interval length, previous cytological abnormality, previous cervical procedure and number of preceding consecutive negative screens. The relationship between these variables and risk of squamous cervicalcancer was determined using survival analysis methods.Results: A total of 388 cases of invasive cervical cancer (252 squamous) were included in the study from a study population o...
TL;DR: A remarkable consequence of the introduction of thalassemia screening in Iran has been the revision of Iran’s abortion policy, demonstrating how effective an integrated screening service can be when it encourages policy adjustment, based on systematic feedback by the recipients of testing.
Abstract: The recent report by Samavat and Modell describing thalassemia screening in Iran is worthy of admiration and even a bit of envy from anyone who has been involved with planning and implementing screening programmes. Beginning 20 years ago, government policy makers in Iran developed a nationwide, fully integrated primary health care system that also recognized the importance of targeted education and data collection. Emphasis was initially placed on communicable diseases, but once this group of disorders was brought under control the focus broadened to include non-communicable diseases as well. The Ministry of Health and Medical Education subsequently chose thalassemia as the index disorder to examine the feasibility of disease prevention in this latter category. Table 1 summarizes the key features of the screening design. This is a good example of couple screening. In addition, the classic criteria for a worthwhile screening programme are satisfied, though perhaps the offer of screening should be mandatory rather than screening itself. The disorder being screened for has serious medical consequences and it occurs sufficiently often to have an important societal impact. A remedy is available to couples with positive test results: avoidance of the disorder’s occurrence in the next generation. The screening methodology is inexpensive and reliable. Diagnostic testing, when needed, is readily available, as are services for termination. A nationwide system is in place to deliver screening services and also to provide education. In addition to reducing the thalassemia birth rate by 70%, a remarkable consequence of the introduction of thalassemia screening has been the revision of Iran’s abortion policy, demonstrating how effective an integrated screening service can be when it encourages policy adjustment, based on systematic feedback by the recipients of testing. When couple screening was initiated in 1997, abortion was not permitted in Iran. Premarital testing avoided the serious dilemma associated with couples’ learning of their risk for the first time during pregnancy, without having termination as an option. Couples’ choices were limited to going forward as they would have without testing, postponing marriage (or, at least, childbearing), or separating and finding other partners. It quickly became apparent, however, that those being tested wanted to have prenatal diagnosis available. This pressure led to ethical discussions by Muslim scholars and others, resulting in a fatwah that allowed abortion during the first 15 weeks after the last menstrual period, when the fetus was diagnosed with thalassemia. Once this revised policy came into effect, the health community was able to notify at-risk couples who had been identified earlier, so that they, too, could avail themselves of this new and important option. When the medical disorder being screened for is inherited in an autosomal recessive manner, it makes logical sense to classify the couple as a screening unit from the outset. Under that condition, further action is called for only when both partners carry the mutation; otherwise the screening test is negative. This can have a large effect on reducing the number of people who need special action on the basis of the result. It is reduced by the square of the prevalence of the mutation in the population in question; if the carrier rate is 5%, only 0.25% of couples need special action. There are no important health implications for an individual carrier. A similar approach to thalassemia screening has been used successfully in several areas of the Mediterranean. By contrast, there has been considerable resistance to using the couple model for preconceptional and prenatal cystic fibrosis screening in the USA, even though a prospective intervention trial found it to be both practical and acceptable. In that country, the prevailing view is that emphasis should be placed on identifying and counselling individual carriers, rather than restricting the focus to situations where both partners are carriers. The different philosophy about how screening for recessively inherited genetic disorders should be conducted in the USA has led to the use of a ‘sequential’ model. Screening is initiated when the woman comes for medical care and opts for cystic fibrosis testing. When a mutation is identified, she is counselled and her partner is sought and counselled. The partner is then tested and, if a mutation is found, the couple receives further counselling. In practice this testing sequence has been associated with a high dropout rate among partners of carrier women, either by refusal to participate or by unavailability, thereby invalidating the purpose of screening. As a further complication, samples submitted for cystic fibrosis testing often lack sufficient information to determine whether they are for screening or other purposes. In other words, no model is being used and no programmatic methodology is in place to assure that screening takes place in an orderly fashion. The couple model would avoid these pitfalls by requiring that both 55