Mammography in Symptomatic and Asymptomatic Patients

Abstract

It is now generally accepted that screening mammography at 1- to 3-year intervals can decrease mortality from breast cancer. Three randomized trials, involving a total of 238,000 women, have reported mortality results. In two trials (HIP and S2C), there was a significant reduction in breast cancer mortality (22 per cent at 18 years and 27 per cent at 8 years). One trial (Mälmo) showed a nonsignificant reduction in mortality at year 9 (5 per cent) and nonsignificant increases in mortality at earlier years. There are little data from randomized trials to support a benefit of mammographic screening in women under 50 years old. The two Swedish studies at last follow-up had 26 and 29 per cent more breast cancer deaths in young women in the group randomized to screening. The HIP study had 25 per cent fewer breast cancer deaths at 18 years in women under age 50 at the start of the trial, but because only 12 patients under age 50 had mammographically detectable tumors (out of 89 cancers diagnosed in the screened group), most of the benefit must be due to physical examinations or increased awareness of breast cancer symptoms. The as yet unpublished results of the Canadian trial in women under age 50 should elucidate the benefit of mammography in this age group. American centers report a malignant biopsy rate of 20 to 30 per cent for clinically occult lesions. This rate should increase as the proportion of women who have had prior mammography increases. High-quality mammography, including magnification technique for evaluation of suspicious lesions, proper localization and excisional biopsy techniques with pathologic correlation, and potentially, fine-needle aspiration, may improve the yield of screening mammography-induced open-biopsy procedures. Magnification technique can improve mammographic assessment of the extent of the tumor and guide re-excision for patients being considered for breast-conserving therapy. In the irradiated breast, in our experience, mammography alone detected 35 per cent of recurrent cancers in the irradiated breast. We recommend routine mammographic follow-up of the irradiated breast, including magnification of the local excision site, at 6 months, 1 year, and annually thereafter.