Long-term outcome of hypofractionated postoperative radiotherapy for breast cancer

Objective: To evaluate the effect, duration and toxicity of postoperative hypofractionated radiotherapy (HOFRT) for breast cancer. Methods: From Mar. 1995 to Dec. 1997, 60 patients were randomized into HOFRT (n=30) group or conventional radiotherapy (CRT, n=30) group. The internal mammary chain (IMC), chest wall and axillo-supraclavicular area were treated according to TNM stage and the number of positive axillary lymph nodes. The chest wall was treated by two opposing parallel tangential fields with 6 MV X-ray in HOFRT group. The axillo-supraclavicular area was treated with 6 MV X-ray plus electron beams. The IMC was treated with 14 MeV electron beams. The irradiation dose was 23 Gy in 4 fractions over 17 days in HOFRT group (5.0 Gy on D1 and 3, 6.5 Gy on D15 and 17) and 45-50 Gy in 20-25 fractions over 4-5 weeks in CRT group. Irradiation boost of 10-15 Gy in 5-6 fractions to the axilla area was given to 10 patients in HOFRT group and 9 in CRT group. Results: In HOFER and CRT groups, the 10- year overall survival rates were 56% and 39%; For patients with stage III disease in the two groups, the 10- year overall rates and locoregional recurrence rates were 41% and 52% (P>0.05), and 13% and 10% (P >O.05), respectively. Lymphoedema and hypoactivity of arm induced by radiotherapy were fewer in HOFRT group than CRT group (23% vs 11% and 3% vs 7% ). Grade 2 and 3 acute epidermidis, having extended the course of treatment, was significantly fewer in HOFRT group than CRT group (10% vs 43%, P <0.01 ). Conclusions: Postoperative HOFRT is safe and effective for breast cancer. The local recurrence, survival rate and late side effects in HOFRT group are comparable to those in CRT group. (authors)