Mammographic screening: patterns of use and estimated impact on breast carcinoma survival.
BACKGROUND: Although many studies support the life-saving potential of screening mammography, the actual utilization of screening and the impact of the actual pattern of screening use on the breast carcinoma death rate, remain incompletely understood. In the current report, the authors describe patterns of screening use among women who were examined at a large screening and diagnostic service and estimate the added mortality associated with missed screening mammograms. METHODS: Mammography use was assessed in a population of 72,417 women who received a total of 254,818 screening mammograms at the Massachusetts General Hospital (MGH) Avon Comprehensive Breast Center (Boston, MA) between January 1, 1985, and February 19, 2002. A computer simulation of breast carcinoma growth, spread, and detection of breast carcinoma was used to estimate the likely health consequences of various types of screening use. RESULTS: Both prompt return for annual screening and full use of screening over extended periods of time were rare, and comparison of the MGH population with other populations revealed that the low level of use observed in the MGH population was not atypical. Only 6% of women who received a mammogram in 1992 received all annual mammograms that were available over the next 10 years; the mean number of mammograms received during this period was 5.06, or 51% of the number recommended by the American Cancer Society. Computer simulation results indicate that this underutilization of screening should result in higher mortality levels. Women from traditionally underserved socioeconomic, racial, and ethnic groups, women without insurance, and women who did not speak English had lower levels of use compared with other women. Lower levels of use also were observed among women receiving their first mammogram or who in the past had not returned promptly. Women ages 55-65 years had higher levels of use than did younger or older women. Women who previously had breast carcinoma also had higher levels of screening use. Nonetheless, none of the subpopulations of women stratified by age, race, ethnicity, zip code, income,language, insurance, status, previous screening use, or medical history exhibited a widespread propensity to promptly return for annual screening over an extended period of time. CONCLUSIONS: By many measures, the current analysis is one of the most detailed descriptions of screening use to date. The authors observed a level of screening use that was disappointingly low, with potentially negative health-related consequences, among women across categories defined by racial, ethnic, socioeconomic, and geographic characteristics; insurance status; language; age; medical history; and previous screening use. Improvements in the promptness with which women return to screening appear to have the potential to lead to considerable reductions in breast carcinoma death.