Predictors for complete pathological response for stage II and III rectal cancer following neoadjuvant therapy - A systematic review and meta-analysis

Background: There has been an increasing interest in the complete pathological response (pCR) in rectal cancers following neoadjuvant therapy. The aim of this study was to identify predictive factors of pCR in locally advanced rectal cancer following neoadjuvant therapy. Methods: The studies identi fi ed were appraised with standard selection criteria. The selection criteria included studies on patients with stage II or III rectal cancer who underwent neoadjuvant therapy. Results: Patients with pCR are more likely to be older (p = 0.0002), have cancers closer distance to the anal verge (p < 0.00001), smaller tumors (P < 0.0001), no clinical lymph nodes involvement (p = < 0.00001) and waited more than eight weeks until de fi nitive surgery (p = 0.002). There was no difference in gender (p = 0.15) and tumor differentiation (p = 0.21). Conclusions: The 'Watch and Wait' approach may be appropriate for selected patients. Patients with lower rectal cancers, smaller tumors, and negative clinical lymph node involvement may be more likely to achieve pCR following neoadjuvant therapy. (C) 2020 Elsevier Inc. All rights reserved.