Adjuvant radiotherapy in operable rectal cancer: A systematic review☆

Abstract 

The aim of this study was to systematically review all randomized trials of adjuvant radiotherapy in patients with operable rectal cancer. The outcome measures used were survival, loco-regional control, and treatment-related mortality. A systematic search strategy was used to identify all published randomized studies in which surgery alone was compared with surgery plus adjuvant radiotherapy. The strategy included a search of Medline, meeting abstracts, and registers of clinical trials. The data were abstracted and analyzed using the standard meta-analytic methods of odds ratio (fixed effects) and rate difference (random effects). Thirty-three relevant studies were identified and data could be obtained from 27 of them. Adjuvant radiotherapy significantly improved local control, by 9% in absolute terms. The benefit in survival was less, ie, 3%. There was, overall, no increase in treatment-related mortality associated with adjuvant radiotherapy. However, there was a 3% absolute increase in treatment-related deaths in patients treated with short-course preoperative radiotherapy. There are definite benefits from adjuvant radiotherapy, particularly in terms of improved local control. These benefits do not, however, fully translate into improved survival. This systematic review draws attention to the difficulties in synthesizing evidence concerning the effectiveness of complex and evolving technologies. The historical evidence is consistent with the hypothesis that radiotherapy has simply been an elaborate means of compensating for variability in surgical technique. The next generation of trials needs to address questions concerning selection criteria, ie, which patients benefit from adjuvant treatment and which patients do not. Another important issue is whether the combination of chemotherapy and radiation is superior to radiation alone or, indeed, whether adjuvant chemotherapy alone is sufficient for patients at high risk of recurrence. Copyright © 2002 by W.B. Saunders Company