Elective irradiation with the electron beam after mastectomy for breast cancer.

From 1963 to 1970, 380 patients have received elective treatment with the electron beam after radical mastectomy for breast cancer. One hundred and twenty-nine patients received treatment to the supraclavicular and internal mammary lymph node areas only, and 251 patients received treatment to the chest wall as well as to the areas of peripheral lymphatic drainage. Analysis of the results shows the value of elective irradiation of occult deposits of disease since the incidence of local recurrences is significantly less than would be anticipated in this group of patients.