Five RCTs, with 2,519 patients, were included in the review. One trial was scored with 1 point on the Jadad scale; the remaining four trials scored 2 points. There was no evidence of publication bias.
The meta-analysis showed no statistically significant differences between the radiotherapy and chemoradiotherapy groups for survival, cancer-related survival, local recurrence, resectability, curative resectability, sphincter preservation, postoperative mortality or postoperative morbidity.
Chemoradiotherapy was associated with a higher complete response rate (OR 3.0296, 95%CI 1.9449 to 4.7192; five RCTs), but higher rates of toxicity (OR 3.9939, 95%CI 1.7364 to 9.1867; three RCTs). For the toxicity result, the authors stated that there was significant heterogeneity, but no further investigation of this was reported.
The meta-analysis of preoperative short-course radiotherapy versus preoperative chemoradiotherapy showed no difference between the two groups for survival, local recurrence, mortality, resectability or sphincter preservation. Morbidity was lower following chemoradiotherapy (OR 0.3219, 95%CI 0.1854 to 0.559; five RCTs) and the rate of resection leaving no residual tumour was higher following chemoradiotherapy (OR 2.7253, 95%CI 1.7089 to 4.3463; five RCTs) compared with short-course radiotherapy.