Value of contralateral surveillance mammography for primary breast cancer follow-up.

Mammographic screening of the contralateral breast is often advocated during follow-up of women previously treated for primary operable breast cancer. The purpose of this study was to determine the value of this investigation. Between 1987 and 1995 a total of 5102 contralateral screening mammograms were performed biennially on 2511 women aged </= 70 years following treatment for primary operable breast cancer. Sixty-five metachronous contralateral breast cancers were identified: 21 (32%) at routine clinical examination, 24 (37%) at mammography, and 20 (31%) by patients between routine follow-up appointments. The prognostic features of metachronous cancers were better or similar to those of the first cancer in 59 of 65 (91%) cases. Because of the favorable prognostic characteristics of the contralateral cancer, mammographic screening may have contributed to the long-term survival of 16 of 26 women in whom the histologic characteristics of the first cancer predicted a good prognosis. The cancer detection rate with mammography for these women was 6.5 per 1000 contralateral mammogram investigations at a cost of pound3852 per cancer detected. The results of this study suggest that surveillance mammography of the contralateral breast is of value in women whose first cancer predicted a favorable prognosis.