Local recurrence of adenocarcinoma of the rectosigmoid. Is postoperative adjuvant radiotherapy justified?

Adjuvant postoperative radiation therapy has been suggested for adenocarcinoma of the rectum and sigmoid colon to reduce the incidence of local recurrences. Determination of this incidence is necessary to optimally employ such adjuvant therapies. Ninety-nine patients with adenocarcinoma of the rectum or sigmoid who had surgery from 1976-1984 were reviewed. Follow-up ranged from one to eight years (average 4.1 years). Twenty-three patients had gross unresected residual tumor due to local invasion. Fifteen of the remaining 76 have developed recurrences (20 percent). Two patients (2.6 percent) had local recurrences without concurrent regional or distant metastases. Thus local recurrences rarely are encountered without concurrent regional or distant metastases. Therefore, postoperative radiation therapy to prevent local recurrences is not justified, given the small number of patients potentially benefited. Treatment modalities will need to address regional and distant metastases in addition to local recurrences.