Preoperative radiotherapy for resectable rectal cancer: A meta-analysis

CONTEXT: The benefit of adjuvant radiotherapy for resectable rectal cancer has been extensively studied, but data on survival are still equivocal despite a reduction in the rate of local recurrence. OBJECTIVE: To assess the effectiveness of preoperative radiotherapy followed by surgery in the reduction of overall and cancer-related mortality and in the prevention of local recurrence and distant metastases. DATA SOURCES: Computerized bibliographic searches of MEDLINE and CANCERLIT (1970 to December 1999), including non-English sources, were supplemented with hand searches of reference lists. The medical subject headings used were rectal cancer, radiotherapy, surgery, RCT, randomized, and clinical trial. STUDY SELECTION: Studies were included if they were randomized controlled trials (RCTs) comparing preoperative radiotherapy plus surgery with surgery alone and if they included patients with resectable histologically proven rectal adenocarcinoma, without metastatic disease. Fourteen RCTs were analyzed. DATA EXTRACTION: Data on population, intervention, and outcomes were extracted from each RCT according to the intention-to-treat method by 3 independent observers and combined using the DerSimonian and Laird method. DATA SYNTHESIS: Radiotherapy plus surgery compared with surgery alone significantly reduced the 5-year overall mortality rate (odds ratio OR] 0.84; 95% confidence interval CI], 0.72-0.98; P =.03), cancer-related mortality rate (OR, 0.71; 95% CI, 0.61-0.82; P<.001), and local recurrence rate (OR, 0.49; 95% CI, 0.38-0.62; P<.001). No reduction was observed in the occurrence of distant metastases (OR, 0.93; 95% CI, 0.73-1.18; P =.54). CONCLUSIONS: In patients with resectable rectal cancer, preoperative radiotherapy significantly improved overall and cancer-specific survival compared with surgery alone. The magnitude of the benefit is relatively small and criteria are needed to identify patients most likely to benefit from adjuvant radiotherapy. JAMA. 2000;284:1008-1015