Contralateral breast cancer after limited surgery plus radiotherapy of early mammary tumors

The series of 701 patients of the Milano clinical trial on Tl No breast cancer (1973-1980) was investigated to compare the incidence of contralateral breast cancer in the Halsted group (not irradiated) and in the QU.A.RT. group (irradiated on the operated breast with a total dose of 50 Gy plus a limited boost of 10 Gy). In March 1986, a contralateral breast cancer was diagnosed in 17/349 patients (4.9%) of the Halstead group and in 18/352 patients (5.1%) of the QU.A.RT. group after a median follow-up of 108 months. The sites of contralateral cancer were superimposable in the two groups of patients, with a constant prevalence of external quadrants, despite the great difference of dose distribution in the irradiated patients. Data on the incidence of contralateral breast cancer failed to demonstrate an oncogenic effect of irradiation to date, but follow-up is still in progress. (author)