Therapeutic efficacy of postoperative irradiation on carcinoma of the breast

: From July 1973 to October 1983, 77 patients received mastectomy followed by postoperative irradiation at National Medical Center Hospital. The patients were classified as follows: 9 cases as stage I, 30 cases as stage II, 28 cases as stage IIIa, 7 cases as stage IIIb and 2 cases as stage IV. Irradiation fields were the parasternal and supraclavicular region. The axis of the irradiation fields to parasternal and supraclavicular regions were set up at 3.5 cm from the surface of the body and they were irradiated separately. The irradiation fields were about 0.5 cm apart from each other. Parasternal region contained bilateral parasternal lymphnodes. In some cases, the centersplit was used to prevent the radiation myelopathy. Prophylactic irradiation to axilla was performed by electron beam from October 1974 to September 1977. Prophylactic irradiation to chest wall has not been done since 1973. The five and ten years survival rates of stage II were 93.2% and 86.3%, stage IIIa were 61.9% and 55. 7%, Stage IIIb were 71.4% and 35.7%. The rate of the local recurrence at the supraclavicular region was 0% as stage I, 6.7% as stage II, 0% as stage IIIa and 14.3% as stage IIIb. Among the cases with regional lymphnode involvement at the time of mastectomy, the rate of local recurrence at the supraclavicular region was 6.7% in prophylactic irradiation group and it was significantly lower than in non-prophylactic irradiation group (11.5%) (p less than 0.05). The rate of local recurrence to chest wall was 0% as stage I, 6.7% as stage II, 8.0% as stage IIIa and 42.9% as stage IIIb.(ABSTRACT TRUNCATED AT 250 WORDS)