Showing papers by "Elsebeth Lynge published in 2006"

Overdiagnosis, Sojourn Time, and Sensitivity in the Copenhagen Mammography Screening Program

Abstract: The goal of this research was to estimate the overdiagnosis at the first and second screens of the mammography screening program in Copenhagen, Denmark. This study involves a mammography service screening program in Copenhagen, Denmark, with 35,123 women screened at least once. We fit multistate models to the screening data, including preclinical incidence of progressive cancers and nonprogressive (i.e., overdiagnosed) cancers. We estimated mean sojourn time as 2.7 years (95% confidence interval [CI] 2.2–3.1) and screening test sensitivity as 100% (95% CI 99.8–100). Overdiagnosis was estimated to be 7.8% (95% CI 0.3–26.5) at the first screen and 0.5% (95% CI 0.02–2.1) at the second screen. This corresponds to 4.8% of all cancers diagnosed among participants during the first two invitation rounds and following intervals. A modest overdiagnosis was estimated for the Copenhagen screening program, deriving almost exclusively from the first screen. The CIs were very broad, however, and estimates from larger datasets are warranted.

A pooled analysis of bladder cancer case-control studies evaluating smoking in men and women.

Abstract: Objective A recent study suggested that risk of bladder cancer may be higher in women than in men who smoked comparable amounts of cigarettes. We pooled primary data from 14 case–control studies of bladder cancer from Europe and North America and evaluated differences in risk of smoking by gender.

Cancer in Persons Working in Dry Cleaning in the Nordic Countries

Abstract: U.S. studies have reported an increased risk of esophageal and some other cancers in dry cleaners exposed to tetrachloroethylene. We investigated whether the U.S. findings could be reproduced in the Nordic countries using a series of case-control studies nested in cohorts of laundry and dry-cleaning workers identified from the 1970 censuses in Denmark, Norway, Sweden, and Finland. Dry-cleaning work in the Nordic countries during the period when tetrachloroethylene was the dominant solvent was not associated with an increased risk of esophageal cancer [rate ratio (RR) = 0.76; 95% confidence interval (CI), 0.34-1.69], but our study was hampered by some unclassifiable cases. The risks of cancer of the gastric cardia, liver, pancreas, and kidney and non-Hodgkin lymphoma were not significantly increased. Assistants in dry-cleaning shops had a borderline significant excess risk of cervical cancer not found in women directly involved in dry cleaning. We found an excess risk of bladder cancer (RR = 1.44; 95% CI, 1.07-1.93) not associated with length of employment. The finding of no excess risk of esophageal cancer in Nordic dry cleaners differs from U.S. findings. Chance, differences in level of exposure to tetrachloroethylene, and confounding may explain the findings. The overall evidence on bladder. cancer in dry cleaners is equivocal.

What happens when organization of cervical cancer screening is delayed or stopped

Abstract: Objectives: Many countries rely on opportunistic screening, and data on its effectiveness are asked for. We assessed the impact on cervical cancer incidence and mortality of opportunistic screening...

Breast cancer incidence after the introduction of mammography screening: what should be expected?

Abstract: BACKGROUND A prevalence peak is expected in breast cancer incidence when mammography screening begins, but afterward the incidence still may be elevated compared with prescreening levels. It is important to determine whether this is due to overdiagnosis (ie, the detection of asymptomatic disease that would otherwise not have arisen clinically). In the current study, the authors examined breast cancer incidence after the introduction of mammography screening in Denmark. METHODS Denmark has 2 regional screening programs targeting women ages 50 years to 69 years. The programs were initiated in 1991 and 1993, respectively. No screening takes place in the 13 other Danish regions. Data regarding incident breast cancers detected between 1979 and 2001 were retrieved from the Danish Cancer Registry for each screening region and for the rest of Denmark, and time trends in rates for women ages 50 years to 69 years were compared. From 1 program, individual screening data were used to analyze breast cancer incidence in women who were never screened, those who were screened for the first time, or those who previously were screened. RESULTS The incidence of breast cancer was found to have increased regardless of screening. In the screening regions, a marked prevalence peak was observed, and the incidence hereafter was compatible with the level indicated by the 95% confidence limits for the regression curves for the rates in the prescreening period, taking into account the artificial ageing in the program, the influx of newcomers, and variations in the data. Women who had undergone previous screening were found to have the same incidence of breast cancer as women who were never screened. CONCLUSIONS The data from the current study do not provide evidence of overdiagnosis of invasive breast cancer in the 2 Danish screening programs or, if overdiagnosis was found to occur, it was only of limited magnitude. Cancer 2006. © 2006 American Cancer Society.

Cancer mortality in workers exposed to organochlorine compounds in the pulp and paper industry: an international collaborative study.

Abstract: The objective of this study was to evaluate cancer mortality in pulp and paper industry workers exposed to chlorinated organic compounds. We assembled a multinational cohort of workers employed between 1920 and 1996 in 11 countries. Exposure to both volatile and nonvolatile organochlorine compounds was estimated at the department level using an exposure matrix. We conducted a standardized mortality ratio (SMR) analysis based on age and calendar-period-specific national mortality rates and a Poisson regression analysis. The study population consisted of 60,468 workers. Workers exposed to volatile organochlorines experienced a deficit of all-cause [SMR = 0.91; 95% confidence interval (CI), 0.89-0.93] and all-cancer (SMR = 0.93; 95% CI, 0.89-0.97) mortality, with no evidence of increased risks for any cancer of a priori interest. There was a weak, but statistically significant, trend of increasing risk of all-cancer mortality with increasing weighted cumulative exposure. A similar deficit in all-cause (SMR = 0.94; 95% CI, 0.91-0.96) and all-cancer (SMR = 0.94; 95% CI, 0.89-1.00) mortality was observed in those exposed to nonvolatile organochlorines. No excess risk was observed in cancers of a priori interest, although mortality from Hodgkin disease was elevated (SMR = 1.76; 95% CI, 1.02-2.82) . In this study we found little evidence that exposure to organochlorines at the levels experienced in the pulp and paper industry is associated with an increased risk of cancer, apart from a weak but significant association between all-cancer mortality and weighted cumulative volatile organochlorine exposure.

Performance of clinical mammography: a nationwide study from Denmark.

Abstract: Clinical mammography is the key tool for breast cancer diagnosis, but little is known about the impact of the organisational set-up on the performance. We evaluated whether organisatorial factors influence the performance of clinical mammography. Clinical mammography data from all clinics in Denmark in the year 2000 were collected and linked to cancer outcome. Use of the National Institute of Radiation Hygiene register for identification of radiology clinics ensured comprehensive nationwide registration. We used the final mammographic assessment at the end of the imaging work-up to determine sensitivity, specificity and accuracy, the latter using a receiver-operating characteristics (ROC) analysis. In 96,534 clinical mammography examinations, sensitivity was 75% and specificity 99%. The presence of at least one high volume-reading radiologist in the clinic increased accuracy (AUC = 0.91 for 2,000 examinations/year, p = 0.017). The examination volume per clinic showed no clear effect on performance, as accuracy was significantly higher in clinics with a medium number of examinations (AUC = 0.93 for 2,000–4,000 examinations/year and 0.90 for >6,000 examinations/year, p = 0.003). Accuracy was significantly lower in regions with high annual utilisation rate of clinical mammography, which means the proportion of examined women in a region (AUC = 0.90 for 3.0–5.0% annual utilisation rate and AUC = 0.93 for 2.0–2.5% annual utilisation rate, and p = 0.001), indicating that clinical mammography worked best in patient populations of purely symptomatic women. Our data indicate that to increase the accuracy of clinical mammography at the community level, the presence of an experienced radiologist should be prioritised ahead of raising the clinic size. © 2006 Wiley-Liss, Inc.

Women's patterns of participation in mammography screening in Denmark

Abstract: The objective of the study is to analyse individual women’s participation patterns in mammography screening in Denmark. The study is set in the capital of Copenhagen and the county of Fyn representing around 95,000 women aged 50–69. The Central Population Register (CPR) was used to define the total target group, and supply information on migrations and deaths. Invitation and participation data came from the mammography screening programmes in Copenhagen (1991–1999) and Fyn (1993–2001), containing personal identification number, data on invitation date, participation and examination date for each screening round. In Copenhagen the coverage went from 70.5% in the first round to 63.1% in the fourth round, and the equivalent data for Fyn is 84.6% in the first round and 82.8% in the fourth round. Of the women eligible for at least three invitation rounds, 52.6% in Copenhagen and 76.4% in Fyn were faithful users, i.e. had participated in all screenings they were invited to. The conclusion is that the programme participation rates tend to overestimate the protection of the individual women covered by the programme. Behind the urban–rural gradient in programme participation is an even greater gradient in programme protection.

Causes of death behind low life expectancy of Danish women.

Abstract: Aims: The authors examined causes of death contributing to the relatively high mortality of Danish women born 1915—45, and evaluated the impact of smoking related causes of death. Methods: Age—period—cohort analysis of mortality of Danish women aged 40—89 in 1960—98. Estimate of the negative curvature in parabola patterns for 50 causes of death. Results: A total of 34 causes of death contributed to the relatively high mortality for women born 1915—45. The main contribution came from smoking-related causes of death. Conclusion: The results indicate a high smoking prevalence to be the main explanation behind the relatively low life expectancy of Danish women born 1915—45.

Breast cancer incidence and mortality in the Nordic capitals, 1970–1998. Trends related to mammography screening programmes

Abstract: The aim of the present study was to relate the time trends in breast cancer incidence and mortality to the introduction of mammography screening in the Nordic capitals. Helsinki offered screening to women aged 5059 starting in 1986. The other three capitals offered screening to women aged 5069 starting in 1989 in Stockholm, 1991 in Copenhagen, and 1996 in Oslo. Prevalence peaks in breast cancer incidence depended on the age groups covered by the screening, the length of the implementation of screening, and the extent of background opportunistic screening. No mortality reduction following the introduction of screening was visible after seven to 12 years of screening in any of the three capitals where significant effects of the screening on the breast cancer mortality had already been demonstrated by using other analytical methods for the evaluation. No visible effect on mortality reduction was expected in Oslo due to too short an observation period. The study showed that the population-based breast cancer mortality trend is too crude a measure to detect the effect of screening on breast cancer mortality during the first years after the start of a programme. The effect of mammography screening on breast cancer mortality has been studied in several rando- mised trials the majority of which have been per- formed in Sweden (14). These studies have shown that it is possible to reduce breast cancer mortality by 2030% at a population level. In an update of four Swedish trials with a follow-up of 16 years, the mortality reduction was 21% (5), and in a 20-year follow-up of the two-county trial a greater than 40% reduction in breast cancer mortality was found (6). National guidelines and recommendations for mam- mography screening, as well as European Guidelines from the European Commission (7), have been issued and have influenced the establishment and organisation of mammography screening as well as the treatment of breast cancer patients. Nationwide screening programmes now exist in Finland, Iceland, Luxembourg, the Netherlands, Sweden, and the

Performance of combined clinical mammography and needle biopsy: a nationwide study from Denmark.

Abstract: Clinical mammography and needle biopsy are key tools for non-operative assessment of breast lesions. We evaluated the performance of all combined tests undertaken in Denmark in 2000. Clinical mammography and needle biopsy data were collected and linked to final cancer outcome, to determine sensitivity, specificity, and predictive values of clinical mammography, needle biopsy, and combined test. In 2000, 6709 combined tests were performed in 36 mammography clinics in Denmark. The combined test was consistently more sensitive than any single test, increasing the proportion of women correctly identified with breast cancer by 9% compared with clinical mammography alone. For concordant combined tests (i.e. either both benign or both malignant), specificity and positive predictive value were 100%, sensitivity was 99.1%, and positive predictive value was 99.6%. Therefore, Danish patients with a malignant concordant combined test can proceed directly to definitive surgery without fear of a false-positive diagnosis, and Danish women with a concordant benign combined test can omit surgery without fear of a false-negative diagnosis. In discordant cases, our results showed that any of the two tests with a suspicious or malignant result indicated a high risk of cancer, and excisional diagnostic biopsy therefore still has an important role to play.

Do changes in lymph node status distribution explain trends in survival of breast cancer patients in Denmark

Abstract: We studied the impact on survival of changes in breast cancer patients' distribution by lymph node status at the time of diagnosis. Our study included breast cancer patients diagnosed from 1978 to 1994 in Denmark, where the treatment schemes for breast cancer patients were fairly stable, and where mammography screening was limited. We measured lymph node status by the proportion of positive lymph nodes of all excised lymph nodes, as assessed by a pathologist. This measure was available for two-thirds of the breast cancer patients. The outcome was 5-year relative survival. Changes in lymph node status distribution explained half of the improvement in 5-year relative survival, and seem to be the single most important cause behind the improved survival of breast cancer patients in Denmark.