Preoperative short-course radiotherapy (5\u2009×\u20095 Gy) with delayed surgery versus preoperative long-course radiotherapy for locally resectable rectal cancer: a meta-analysis

Abstract

Preoperative short-course radiotherapy (PSRT) and preoperative long-course radiotherapy (PLRT) are standard treatment regimens for locally advanced rectal cancer. However, whether the efficacy and safety of PSRT with delayed surgery (more than 4 weeks) are superior to those of PLRT remains unresolved and was explored in this meta-analysis. Studies published in PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov databases were systematically searched. RevMan 5.3 was used to calculate pooled hazard ratios (HR) and relative risk (RR). Seven studies including 4973 patients were identified in the meta-analysis. Pooled statistics showed that there was no statistically significant difference in overall survival (HR\u2009=\u20091.30, 95% CI 0.58–2.89, P\u2009=\u20090.52) or disease-free survival (HR\u2009=\u20091.10, 95% CI 0.73–1.66, P\u2009=\u20090.64) between the preoperative short-course and long-course radiotherapy groups. Moreover, pathological complete remission, early postoperative complications, treatment-related grade 3/4 toxicity, local recurrence, and distant metastasis were similar between the two groups. Interestingly, a subgroup analysis revealed that preoperative short-course radiotherapy without adjuvant chemotherapy not only resulted in lower treatment-related grade 3/4 toxicity than the long-course radiotherapy group (RR\u2009=\u20090.19, 95% CI 0.08–0.48, P\u2009<\u20090.01) but also resulted in significantly lower overall survival and pathological complete remission (P\u2009=\u20090.02, P\u2009<\u20090.01, respectively). Disappointingly, pooled statistics observed few advantages over long-course radiotherapy in short-course radiotherapy with the adjuvant chemotherapy subgroup. PSRT with delayed surgery was as effective as PLRT for the management of locally resectable rectal cancer. However, not adding additional chemotherapy to PSRT not only significantly decreased grade 3/4 toxicity but also decreased pathological complete remission and overall survival. The protocol for this meta-analysis was prospectively registered with PROSPERO (CRD42019133641)