Short-course preoperative radiotherapy with immediate surgery versus long-course chemoradiation with delayed surgery in the treatment of rectal cancer: a systematic review and meta-analysis.

BACKGROUND: Long-course chemoradiotherapy (LCRT) with delayed surgery or short-course radiotherapy (SCRT) with immediate surgery is probably the most frequent regimen in the treatment of rectal cancer. Debate is still going on whether SCRT or LCRT is more effective. So we performed this meta-analysis to evaluate the safety and efficacy of SCRT with immediate surgery versus LCRT with delayed surgery for the management of rectal cancer.

METHODS: Literature were searched from PubMed, Embase, Web of science, Cochrane Library up to May, 2014. Quality of the randomized controlled trials (RCTs) was evaluated according to the Cochrane's risk of bias tool of RCT. RevMan 5.3 was used for statistical analysis. Pooled risk ratio (RR) and 95% confidence interval (CI) were calculated. Subgroup analysis and sensitivity analysis were employed to explore heterogeneity.

RESULTS: 16 trials were included in the qualitative systematic review. 12 trials were included in meta-analyses. 4 of them were RCTs; other 8 were non-RCTs. Meta-analysis demonstrated that there were no significant differences in overall survival (OS), disease free survival (DFS), local recurrence rate (LRR), distant metastasis rate (DMR), sphincter preservation rate, R0 resection rate and late toxicity. Compared with SCRT, LCRT obviously increased pCR rate [RR=0.15, 95%CI (0.08, 0.28), P=0.003], while LCRT obviously increased the grade 3-4 acute toxicity [RR=0.13, 95%CI (0.06, 0.28), P<0.00001].

CONCLUSIONS: SCRT with immediate surgery is as effective as LCRT with delayed surgery for treatment of rectal cancer in terms of OS, DFS, LRR, DMR, Sphincter preservation rate, R0 resection rate and late toxicity. Though LCRT increased pCR rate, LCRT also increased acute toxicity compared with SCRT. SCRT is a better choice in centers with a long waiting list or lack of medical resources.