Screening with mammography uses X-ray imaging to find breast cancer before a lump can be felt. The goal is to treat cancer earlier, when a cure is more likely. The review includes seven trials that involved 600,000 women in the age range 39 to 74 years who were randomly assigned to receive screening mammograms or not. The studies which provided the most reliable information showed that screening did not reduce breast cancer mortality. Studies that were potentially more biased (less carefully done) found that screening reduced breast cancer mortality. However, screening will result in some women getting a cancer diagnosis even though their cancer would not have led to death or sickness. Currently, it is not possible to tell which women these are, and they are therefore likely to have breasts or lumps removed and to receive radiotherapy unnecessarily. If we assume that screening reduces breast cancer mortality by 15% after 13 years of follow-up and that overdiagnosis and overtreatment is at 30%, it means that for every 2000 women invited for screening throughout 10 years, one will avoid dying of breast cancer and 10 healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily. Furthermore, more than 200 women will experience important psychological distress including anxiety and uncertainty for years because of false positive findings.
Women invited to screening should be fully informed of both the benefits and harms. To help ensure that the requirements for informed choice for women contemplating whether or not to attend a screening programme can be met, we have written an evidence-based leaflet for lay people that is available in several languages on www.cochrane.dk. Because of substantial advances in treatment and greater breast cancer awareness since the trials were carried out, it is likely that the absolute effect of screening today is smaller than in the trials. Recent observational studies show more overdiagnosis than in the trials and very little or no reduction in the incidence of advanced cancers with screening.

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Screening for breast cancer with mammography.

Socioeconomic and racial/ethnic disparities in health care quality have been extensively documented. Recently, the elimination of disparities in health care has become the focus of a national initiative. Yet, there is little effort to monitor and address disparities in health care through organizational quality improvement. After reviewing literature on disparities in health care, we discuss the limitations in existing quality assessment for identifying and addressing these disparities. We propose 5 principles to address these disparities through modifications in quality performance measures: disparities represent a significant quality problem; current data collection efforts are inadequate to identify and address disparities; clinical performance measures should be stratified by race/ethnicity and socioeconomic position for public reporting; population-wide monitoring should incorporate adjustment for race/ethnicity and socioeconomic position; and strategies to adjust payment for race/ethnicity and socioeconomic position should be considered to reflect the known effects of both on morbidity. JAMA. 2000;283:2579-2584

Inequality in quality : Addressing socioeconomic, racial, and ethnic disparities in health care

Study Selection: Eight randomized, controlled trials of mammography and 2 trials evaluating breast self-examination were included. One hundred fifty-four publications of the results of these trials, as well as selected articles about the test characteristics and harms associated with screening, were examined. Data Extraction: Predefined criteria were used to assess the quality of each study. Meta-analyses using a Bayesian randomeffects model were conducted to provide summary relative risk estimates and credible intervals (CrIs) for the effectiveness of screening with mammography in reducing death from breast cancer. Data Synthesis: For studies of fair quality or better, the summary relative risk was 0.84 (95% CrI, 0.77 to 0.91) and the number needed to screen to prevent one death from breast cancer after approximately 14 years of observation was 1224 (CrI, 665 to 2564). Among women younger than 50 years of age, the summary relative risk associated with mammography was 0.85 (CrI, 0.73 to 0.99) and the number needed to screen to prevent one death from breast cancer after 14 years of observation was 1792 (CrI, 764 to 10 540). For clinical breast examination and breast self-examination, evidence from randomized trials is inconclusive. Conclusions: In the randomized, controlled trials, mammography reduced breast cancer mortality rates among women 40 to 74 years of age. Greater absolute risk reduction was seen among older women. Because these results incorporate several rounds of screening, the actual number of mammograms needed to prevent one death from breast cancer is higher. In addition, each screening has associated risks and costs.

Breast Cancer Screening: A Summary of the Evidence for the U.S. Preventive Services Task Force

This article develops a conceptual model of cultural competency's potential to reduce racial and ethnic health disparities, using the cultural competency and disparities literature to lay the foundation for the model and inform assessments of its validity. The authors identify nine major cultural competency techniques: interpreter services, recruitment and retention policies, training, coordinating with traditional healers, use of community health workers, culturally competent health promotion, including family/community members, immersion into another culture, and administrative and organizational accommodations. The conceptual model shows how these techniques could theoretically improve the ability of health systems and their clinicians to deliver appropriate services to diverse populations, thereby improving outcomes and reducing disparities. The authors conclude that while there is substantial research evidence to suggest that cultural competency should in fact work, health systems have little evidence about which cultural competency techniques are effective and less evidence on when and how to implement them properly.

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Can Cultural Competency Reduce Racial and Ethnic Health Disparities? A Review and Conceptual Model:

OBJECTIVES: To evaluate the efficacy of the combination of annual screening with mammography, physical examination of the breasts and the teaching of breast self-examination in reducing the rate of death from breast cancer among women aged 40 to 49 years on entry. DESIGN: Individually randomized controlled trial. SETTING: Fifteen urban centres in Canada with expertise in the diagnosis and treatment of breast cancer. PARTICIPANTS: Women with no history of breast cancer and no mammography in the previous 12 months were randomly assigned to undergo either annual mammography and physical examination (MP group) or usual care after an initial physical examination (UC group). The 50,430 women enrolled from January 1980 through March 1985 were followed for a mean of 8.5 years. DATA COLLECTION: Derived from the participants by initial and annual self-administered questionnaires, from the screening examinations, from the patients9 physicians, from the provincial cancer registries and by record linkage to the Canadian National Mortality Data Base. Expert panels evaluated histologic and death data. MAIN OUTCOME MEASURES: Rates of referral from screening, rates of detection of breast cancer from screening and from community care, nodal status, tumour size, and rates of death from all causes and from breast cancer. RESULTS: Over 90% of the women in each group attended the screening sessions or returned the annual questionnaires, or both, over years 2 to 5. The characteristics of the women in the two groups were similar. Compared with the Canadian population, the participants were more likely to be married, have fewer children, have more education, be in a professional occupation, smoke less and have been born in North America. The rate of screen-detected breast cancer on first examination was 3.89 per 1000 in the MP group and 2.46 per 1000 in the UC group; more node-positive tumours were found in the MP group than in the UC group. During years 2 through 5 the ratios of observed to expected cases of invasive breast cancer were 1.26 in the MP group and 1.02 in the UC group. Of the women with invasive breast cancer through to 7 years, 191 and 157 women in the MP and UC groups respectively had no node involvement, 55 and 43 had one to three nodes involved, 47 and 23 had four or more nodes involved, and 38 and 49 had an unknown nodal status. There were 38 deaths from breast cancer in the MP group and 28 in the UC group. The ratio of the proportions of death from breast cancer in the MP group compared with those in the UC group was 1.36 (95% confidence interval 0.84 to 2.21). The survival rates were similar in the two groups. The highest survival rate occurred among women whose cancer had been detected by mammography alone. CONCLUSION: The study was internally valid, and there was no evidence of randomization bias. Screening with yearly mammography and physical examination of the breasts detected considerably more node-negative, small tumours than usual care, but it had no impact on the rate of death from breast cancer up to 7 years9 follow-up from entry.

Canadian National Breast Screening Study: 1. Breast cancer detection and death rates among women aged 40 to 49 years

Critical decisions made 20 years ago by those who planned the randomized trial at the Health Insurance Plan (HIP) of Greater New York to determine the efficacy of periodic screening for breast cancer are detailed. These decisions affected the age group to be screened, screening modalities, frequency of screening, sample size, primary measures for testing efficacy, and period of follow-up (long term). Results of follow-up, 16 years after entry, indicate that mortality due to breast cancer continues to be lower among study women than controls. Numerically, the differential has been stable; relatively, it has decreased. It is estimated that the study group would have experienced about a 30% reduction in breast cancer mortality if screening had been maintained. Relative case survival rates over a 14-year period after diagnosis show changes in contours of trend lines that result from screening. The study group's trend is slightly concave in contrast to the usual convex curve for the controls. The contour of the curve is more decidedly concave among subjects detected through mammography alone than for other subgroups detected through screening, although the relative survival rate remains highest in the mammography only group. Uncertainty persists about effects of screening in the HIP study on breast cancer mortality among women aged 40-49 years at entry.

Selection, follow-up, and analysis in the Health Insurance Plan Study: a randomized trial with breast cancer screening.

A prospective study of breast cancer risk factors was undertaken in conjunction with an evaluation of periodic breast cancer screening with mammography (soft-tissue X ray) and clinical examination in women 40-64 years old. The screening study was initiated in December 1963 by the Health Insurance Plan of Greater New York in cooperation with 23 of its affiliated medical groups and then began to be accompanied by the risk-factor study. Among 20211 women initially screened a detection rate of 2.72/1000 women occurred as compared with a rate of 1.62/1000 in the control group (no special screening). The risk-factor data concern cancers detected at the initial examination or the first annual reexamination and the cases detected between these examinations (total of 101 cancers). About 81% of initially-screened women had a first annual reexamination. Women participating in the initial screening examinations tended to be younger more educated and generally more concerned about cancer. Ratios of relative risks for variables in which a definite or suggestive relationship with breast cancer existed included never-married vs. married (2.3) 1-2 vs. more pregnancies (2.0) menarche under 12 vs. at 15 or older (1.7) 30 or more years of menstrual activity vs. less than 30 years (1.4) 1 or more breast conditions vs. none (3.1) and history of 1 or more sisters with breast cancer vs. none (1.9). No clear-cut relationship emerged involving age at first and age at last pregnancy age at menopause or interval since last menopause. The somewhat greater risk apparent at first glance for women with some college dissipated when adjustments were made for marriage and parity. No relationship involving duration of breast feeding was noted although only a small proportion of the women had long periods of lactation.

The search for risk factors in breast cancer.

Results from the randomized trial underway in the Health Insurance Plan of Greater New York to determine the efficacy of periodic screening with mammography and palpation of the breast have been examined to determine the effect of screening on racial differences in breast cancer survival rates. Consistent with experience in general populations, the control group showed a lower five-year survival rate among non-White women with breast cancer than among White women. In the study group, 65 per cent of whom participated in the screening program, there was no differential in the survival rates of the two racial groups. The elimination of the unfavorable status among non-Whites through screening does not appear to be explained by various artifacts explored. Secondary prevention measures may offer the possibility of reducing or closing the gap in breast cancer survival rates between White and non-White women.

P Strax

Papers

Selection, follow-up, and analysis in the Health Insurance Plan Study: a randomized trial with breast cancer screening.

The search for risk factors in breast cancer.

Prospects for eliminating racial differences in breast cancer survival rates.

Proceedings: Changes in 5-year breast cancer mortality in a breast cancer screening program.