Cancer in the Contralateral Breast after Radiotherapy for Breast Cancer

BREAST cancer will develop in approximately one woman in nine, 1 and such patients are at very high risk for second cancers in the other breast. 2 The relatively good survival after treatment for breast cancer (over 70 percent at five years) provides ample opportunity for a new breast cancer to evolve; the development of a new cancer may be related to reproductive or dietary factors, genetic influences, environmental exposure, or treatment for the first tumor. In the past, radiotherapy has been used chiefly in conjunction with extensive surgery to treat primary breast cancer. Today it is common to treat early disease . . .