Short-course Versus Long-course Preoperative Radiotherapy plus Delayed Surgery in the Treatment of Rectal Cancer: a Meta-analysis.

BACKGROUND:Short-course preoperative radiation (SCRT) with delayed surgery was found to increase pathologic complete response (pCR) rates in several trials. However, there was no clear answer on whether SCRT or long-course chemo-radiotherapy (LCRT) is more effective. Therefore we conducted this meta-analysis to evaluate the safety and efficacy of SCRT versus LCRT, both with delayed surgery, for treatment of rectal cancer. MATERIALS AND METHODS:The literature was searched from PubMed, EMBASE, Web of Science, Cochrane Library and clinicaltrials.gov up to November, 2014. Quality of the randomized controlled trials (RCTs) was evaluated according to the Cochrane's risk of bias tool of RCT. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to rate the level of evidence. Review Manager 5.3 was employed for statistical analysis. Pooled risk ratios (RRs) and 95% confidence intervals (CIs) were calculated. RESULTS:Three RCTs, with a total of 357 rectal cancer patients, were included in this systematic review. Meta- analysis results demonstrated there were no significantly differences in sphincter preservation rate, local recurrence rate, grade 3~4 acute toxicity, R0 resection rate and downstaging rate. Compared with SCRT, LCRT was associated with significant increase in the pCR rate [RR=0.49, 95%CI (0.31, 0.78), P=0.003]. CONCLUSIONS:In terms of sphincter preservation rate, local recurrence rate, grade 3~4 acute toxicity, R0 resection rate and downstaging rate, SCRT with delayed surgery is as effective as LCRT with delayed surgery for management of rectal cancer. LCRT significantly increased pCR rate compared with SCRT. Due to risk of bias and imprecision, further multi-center large sample RCTs were needed to confirm this conclusion.