Randomised trial of surgery alone versus surgery followed by radiotherapy for mobile cancer of the rectum. Medical Research Council Rectal Cancer Working Party.

BACKGROUND: Although surgery is the treatment of choice for rectal cancer, local recurrence is common even after apparently curative resection. We aimed to assess the role of postoperative radiotherapy in reducing rates of local recurrence, and improving disease-free and overall survival in patients with mobile Dukes' stage B and C rectal cancers.

METHODS: We carried out a prospective, randomised trial of surgery alone (n = 235) versus surgery followed 4-6 weeks later by radiotherapy (n = 234), of 40 Gy in 20 fractions of 2 Gy over 4 weeks. The 469 patients, from 46 hospitals in the UK and the Republic of Ireland, were randomised between 1984 and 1989, and followed up for a minimum of 5 years or to death.

FINDINGS: 284 patients died, 145 of 235 allocated surgery alone and 139 of 234 allocated postoperative radiotherapy. The hazard ratio for overall survival was 0.84 (95% CI 0.65-1.07, p = 0.17). At 5 years' follow-up 79 patients who received surgery alone and 48 who received postoperative radiotherapy had had local recurrence (hazard ratio 0.54 [0.38-0.77], p = 0.001). The corresponding numbers with distant recurrence were 83 and 75 (hazard ratio 0.85 [0.63-1.114], p = 0.18). The hazard ratio for disease-free survival was 0.85 (0.65-1.08; p = 0.18). Radiotherapy was generally well tolerated; assessment of late events showed serious late bowel complications to be rare and not significantly increased after radiotherapy, even when this followed anterior resection.

INTERPRETATION: Our results have provided further evidence of the ability of postoperative radiotherapy to delay and prevent local recurrence of rectal cancer. Although the local recurrence rate in the control group is in keeping with other multi-centre trials of the mid to late 1980s, it is undoubtedly higher than would be regarded as acceptable now. The combination of larger trials required to provide definitive answers on the impact that postoperative radiotherapy will have on survival.