Clinical and histological predictors of contralateral breast cancer.

AIMS: Women previously treated for primary operable breast cancer are at increased risk of developing cancer in the contralateral breast. The purpose of this study was to assess the annual incidence of metachronous contralateral breast cancer (CBC) and to identify factors that predict for its development.

METHODS: A retrospective study was performed on 3211 women aged </=70 years treated for primary operable breast cancer between 1975 and 1995.

RESULTS: Eighty-three developed CBC prior to locoregional or distant recurrence from the first primary. The clinical incidence of CBC was 6.4 per 1000 women years, three to four times the risk of occurrence of breast cancer in the general female population (or a risk of six to eight times to the remaining breast). Strong family history, age of onset <50 years and lobular histology were significant factors predicting for CBC in univariate and multivariate models. Other clinical factors (previous hormone therapy, chemotherapy, radiotherapy) or histological factors (DCIS, invasive tumour size, grade, vascular invasion, lymph node and oestrogen receptor status) were not significant predictors for CBC.

CONCLUSIONS: In women previously treated for primary operable breast cancer, early age of onset and a strong family history are predictors for the subsequent development of metachronous CBC. Ipsilateral mastectomy with contralateral prophylactic mastectomy with or without immediate breast reconstruction is a reasonable option for a young woman diagnosed with breast cancer and who has a strong family history, particularly if the cancer has histological features suggesting a good prognosis.