Context The benefit of adjuvant radiotherapy for resectable rectal cancer h
as been extensively studied, but data on survival are still equivocal despi
te 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 wi
th 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 tr
ials (RCTs) comparing preoperative radiotherapy plus surgery with surgery a
lone and if they included patients with resectable histologically proven re
ctal adenocarcinoma, without metastatic disease. Fourteen RCTs were analyze
d.
Data Extraction Data on population, intervention, and outcomes were extract
ed from each RCT according to the intention-to-treat method by 3 independen
t observers and combined using the DerSimonian and Laird method.
Data Synthesis Radiotherapy plus surgery compared with surgery alone signif
icantly 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 rat
e (OR, 0.71; 95% CI, 0.61-0.82; P<.001), and local recurrence rate (OR, 0.4
9; 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 radioth
erapy significantly improved overall and cancer-specific survival compared
with surgery alone. The magnitude of the benefit is relatively small and cr
iteria are needed to identify patients most likely to benefit from adjuvant
radiotherapy.