Contralateral breast cancer: a clinico-pathological study of second primaries in opposite breasts after treatment of breast malignancy.

Background: Breast cancer is by far the most frequent cancer of women (23 % of all cancers), ranking second overall when both sexes are considered together. Contralateral breast cancer (CBC) is becoming an important public health issue because of the increased incidence of primary breast cancer and improved survival. The present communication concerns a study to evaluate the role of various clinico-pathological factors on the occurrence of contralateral breast cancer. Materials and Methods: A detailed analysis was carried out with respect to age, menopausal status, family history, disease stage, surgery performed, histopathology, hormone receptor status, and use of chemotherapy or hormonal therapy. The diagnosis of CBC was confirmed on histopathology report. Relative risk with 95%CI was calculated for different risk factors of contralateral breast cancer development. Results: CBC was found in 24 (4.5%) out of 532 patients. Mean age of presentation was 43.2 years. Family history of breast cancer was found in 37.5% of the patients. There was statistically significant higher rate (83.3%) of CBC in patients in age group of 20-40 years with RR=11.3 (95% CI: 1.4, 89.4, p=0.006) seen in 20-30 years and RR=10.8 (95% CI:1.5-79.6, p=0.002) in 30-40 years as compared to older age of 60-70 years. Risk of development was higher in premenopausal women (RR=8.6, 95% CI: 3.5-21.3, p≤0.001). Women with family history of breast cancer had highest rate (20.9%) of CBC (RR=5.4, 95% CI: 2.5-11.6, p≤0.001). Use of hormonal therapy in hormone receptor positive patients was protective factor in occurrence of CBC but not significant (RR=0.7, 95% CI: 0.3-1.5, p=0.333). Conclusions: Younger age, premenopausal status, and presence of family history were found to be significant risk factors for the development of CBC. Use of hormonal therapy in hormone receptor positive patients might be protective against occurrence of CBC but did not reach significance.