503P - Prognostic factors of chemo-radiotherapy efficacy in patients with locally-advanced rectal cancer

Abstract

Background: We decided to evaluate preoperative clinical factors associated with progression free survival, overall survival and tumor regression in patients with locally-advanced rectal cancer after chemo-radiotherapy. Methods: we analyzed prospective database of patients with locally-advancded rectal cancer (cT3-4N0-2M0) who received preoperative chemo-radiotherapy followed by surgery in our center from 2004 to 2013. Multivariate regression analyses was performed to evaluate odds of absent morphological response (Dworak tumo regression rate system 0-2) and hazards of progression and deaths. Statistical analyses was performed with SPSS v.20. Results: Chemo-radiotherapy followed by surgery was performed in 457 patients with locally-advanced rectal cancer. The median f.-up was 46 months (2-141), 3-year progression free survival and overall survival were 79% and 91%, respectively. Multivariate regression analyses revealed factors associated with tumor regression rate 0-2 as high level (above normal range) CEA (carcinoembryonic antigen) before chemo-radiotherapy (OR 1.49 95%CI 1.11-2.02, p = 0.008), neutrophils count ≥ 7,000/µl (OR 2.29, 95%CI 1.0-5.2, p=0.05) and cT4 (OR 3.73, 95%CI 2.03-6.86, p < 0.001). Independent negative prognostic factors for progression free survival were perineural invasion (HR 3.1, 95% CI 1.43-6.89, p<0,001), neutrophil/lymphocyte ratio before surgery ≥ 3 (HR 1.8, 95%CI 1.37-2.42, p=0.01) and ypT3-4 or/and N + (HR 1.82, 95%CI 0.45-0.92, p<0.01). For overall survival: ypT3-4 or/and N + (HR 1.9, 95%CI 1.3-2.65, p<0.01), lymphatic vessel invasion (HR 2.4, 95%CI 1.27-4.59, p<0.01) and leucocytes count before surgery ≥11,000/µl (HR 3.1, 95%CI 1.33-7.33, p<0.01). Conclusions: ypTNM after preoperative chemo-radiotherapy more effective than cTNM predicts progression free and overall survival in patients with localy-advanced rectal cancer. Legal entity responsible for the study: Mikhail Fedyanin. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.