Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project

Introduction Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities indications for neoadjuvant may be controversial. Aim of this study was to assess the trends preoperative outcomes patients with cancer included Rectal Cancer Registry Spanish Associations Surgeons. Method This is a STROBE-compliant retrospective analysis prospective database. All operated on curative intention were included. Analyses performed compare use neoadjuvant/adjuvant three timeframes: I)2006–2009; II)2010–2013; III)2014–2017. Survival analyses run 3-year survival timeframes I-II. Results Out 14,391 patients,8871 (61.6%) received treatment. Long-course chemo/radiotherapy most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%,p = 0.0018). complete regression rate slightly (15.6% vs 16% 18.5%; p 0.0093); proportion involved circumferential resection margins (CRM) went down from 8.2% 7.3%and 5.5% (p 0.0004). Neoadjuvant significantly decreased positive CRM lower tumors (OR 0.71, 0.59–0.87, Cochrane-Mantel-Haenszel P 0.0008). Most ypN0 also adjuvant therapy. In MR-defined stage III patients, associated longer local-recurrence-free < 0.0001), cancer-specific 0.0001). benefit smaller cancers. Conclusion There an increasing trend potential overuse rectum. postoperative Involvement reduced after Stage MRcN + benefited most.