The importance of mammographic screening relative to the treatment of women with carcinoma of the breast

Background: The use of mammographic screening for the early detection of breast cancer has been shown to reduce the mortality from breast cancer. However, the impact of mammographic screening relative to the local treatment of the breast (ie, breast-conservation treatment vs mastectomy) is not well established. Methods: An analysis was performed of 206 newly diagnosed and treated breast cancers in 201 women identified in 1989 from a health maintenance organization (US Healthcare, Blue Bell, Pa). The 206 breast cancers were evaluated for eligibility for and actual local treatment of the breast with breast-conserving surgery and definitive breast irradiation as a function of mammographic screening for the early detection of breast cancer. Results: Eligibility for local treatment of the breast with breast-conserving surgery and definitive breast irradiation was significantly increased for the breast cancers detected in women who had undergone mammographic screening compared with the breast cancers detected in women who had not undergone mammographic screening (88% vs 60%, respectively; P P =.40); however, there was a statistically significant difference for the subgroup of women aged 50 years or more (49% vs 21%, respectively; P=.016). Conclusions: These results show that breast cancers detected in women who had undergone mammographic screening were more likely to be eligible for breast-conserving surgery and definitive breast irradiation compared with breast cancers detected in women who had not undergone mammographic screening. For women aged 50 years or more, there was a significant increase in the use of breast-conserving surgery and definitive breast irradiation for eligible breast cancers detected in women who had undergone mammographic screening compared with eligible breast cancers detected in women who had not undergone mammographic screening. (Arch Intern Med. 1994;154:745-752)