Contralateral Breast Cancer: A Clinico-pathological Study of Second Primaries in Opposite Breast after Treatment

Breast cancer is by far the most frequent cancer of women (23% of all cancers), ranking second overall when both sexes are considered together. It is the leading cause of cancer mortality in women and constitutes 14% of female cancer deaths (Parkin et al., 2005). With an estimated 226,870 diagnoses and 39,510 deaths in 2012, breast cancer remains the most commonly occurring and second most lethal cancer among women in the United States (Howlader et al., 2011). Contralateral breast cancer is defined as the occurrence of a second, independent primary breast cancer in the other breast after the initial diagnosis of breast cancer. Current data suggest that between 2% and 11% of patients diagnosed with breast cancer have or will develop bilateral disease (Chen et