Postoperative radiotherapy following mastectomy for high-risk breast cancer: a randomised trial

Grade III, node-positive breast cancer carries a high risk of loco-regional relapse after simple mastectomy. A randomised trial was conducted to assess whether this would be significantly reduced by postoperative radiotherapy. Between 1985 and 1991, 76 patients who had undergone a simple mastectomy and axillary sampling, and whose tumors had been found to be grade III and node-positive, were randomised to receive postoperative radiotherapy to the chest wall and axilla or no further loco-regional treatment. Radiotherapy was delivered with 8 MV X-rays to the axilla and supraclavicular fossa and with 8 MeV electrons to the chest wall, to a dose of 45 Gy in 15 fractions over 3 weeks. All patients have been followed-up until death, or for a minimum of 10 years. All loco-regional recurrences occurred within the first 4 years after mastectomy. There were 26 such events in the 40 patients randomised to the 'watch' policy (65%), as opposed to 9 out of 36 (25%) who received radiotherapy (P<0.01). Ten-year survival was 39% in the radiotherapy arm as opposed to 25% in the no radiotherapy arm. Recruitment to the trial was closed in 1991, when a preliminary safety analysis revealed the size of the effect of radiotherapy, and from then on all node-positive patients with grade III tumours have routinely been given this treatment. Further follow-up has confirmed this finding, as borne out by these 10-year results, which shows that radiotherapy has a significant impact on reducing loco-regional recurrence in patients at high risk after mastectomy. There is an apparent survival benefit although, because of the small numbers in this trial, this has not reached statistical significance. (C) 2002 Elsevier Science Ltd. All rights reserved.