Mammographic screening in women 40-49 years old.

The societal value of mammographic screening in women 40-49 years old is a controversial topic that is subject as much to emotional rhetoric as to scientific insight. This controversy is reflected in part in differences in screening guidelines developed by professional, voluntary, and government organizations. Early results from epidemiologic studies did not demonstrate conclusively that mammographic screening significantly reduces breast cancer mortality in younger women. More recent data obtained over longer periods of follow-up of screened women demonstrate that rnamrnographic screening of 40to 49-year-old women can decrease mortality from breast cancer [1 , 2]. However, the incidence of breast cancer is much lower in women who are 40-49 years old than in women who are more than 50 years old. Consequently, many more young women must be screened to detect a single case of breast cancer. Charges for mammographic screening remain relatively high. Therefore, the relative cost per case of breast cancer detected is higher for younger women than for women over 50 years old. To evaluate the relative benefits and costs of mammographic screening in women less than 50 years old, Eddy et al. [3] used two quantitative, computer-based models (Confidence Profiles [4] and CAN*TROL [5]) by which they analyzed the epidemiologic evidence and estimated the health and economic consequences of adding mammography to annual breast physical examinations in women 40-49 years old. Breast cancer mortality data from the Health Insurance Plan (HIP) were used in the Confidence Profile model to compute an ensemble estimate of the effectiveness of mamrnographic screening for reducing breast cancer mortality in women in this age group. The effects of methodologic biases on breast cancer mortality reductions in the HIP study were considered in deriving a confidence profile for the estimate. These results for 4 years of annual rnamrnographic screening suggest that the addition of mammograms to annual breast physical examinations in 40to 49-year-old women yielded a 21 % reduction in breast cancer mortality over an 18-year period. However, the 95% limits of uncertainty for this estimate range from a 6% increase to a 56% reduction in breast cancer mortality. The second computer-based model, CAN*TROL, was used to estimate the impact of adding mammography to an annual physical breast examination for a 40-year-old, asymptomatic woman at average risk for breast cancer. This estimate suggests that the addition of mammography reduces the risk of death from breast cancer over the next 1 0 years from 82 in 10,000 to 60 in 10,000, a relative reduction of 27%. For women with breast cancer in this age group, the addition of mammographic screening would increase the average survival by 3.5 years. The CAN*TROL computer model was also used to estimate the net health benefit of mammographic screening of all women who are 40-49 years old. The estimate assumes that 25% (4.5 million) of all 40to 49-year-old women in the United States follow a recommendation for annual mammographic screening from 1 987 to the year 2000. Current breast cancer incidence and mortality rates were used to predict approximately 23,400 breast cancers and 10,700 breast cancer deaths in this population in the year 2000. Annual mammographic screening would reduce the number of breast cancer deaths in the year 2000 by about 373 or 3.5%. The cumulative number of person-years saved as a result of screening was estimated as 8313. The Confidence Profile-generated estimate of percentage reduction in breast cancer mortality was then used to estimate costs associated with mammographic screening. With the