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.