MO2-2-5The efficacy and safety of neoadjuvant mFOLFOXIRI and XELOX for locally advanced rectal cancer: A retrospective study

Abstract Background A standard treatment for locally advanced rectal cancer (LARC) (Ra or Rb, T2 N+, T3/4 Nany) is chemoradiotherapy (CRT) followed by surgery in Western countries. The CRT could reduce the risk of local recurrence but failed to improve the overall survival (OS). The CRT often cause complications such as sexual, urinary and bowel dysfunction. Neoadjuvant chemotherapy (NAC) showed favorable R0 resection rate in several studies and might improve OS. Oxaliplatin and Capecitabine (XELOX) is the standard adjuvant chemotherapy for pStage III colon cancer, on the other hand Fluorouracil, Leucovorin, Oxaliplatin and Irinotecan (FOLFOXIRI) showed higher response rate than doublet therapy. The best regimen as NAC for the LARC still unclear. Purpose The purpose of this study was to investigate the efficacy and safety of neoadjuvant modified FOLFOXIRI (mFOLFOXIRI) and XELOX followed by laparoscopic surgery for the patients (pts) with LARC retrospectively. Method The pts with LARC who received XELOX and FOLFOXIRI as NAC between Jan 2015 and Aug 2018 were investigated retrospectively. Result Forty nine pts received mFOLFOXIRI and 25 pts received XELOX. The characteristics (mFOLFOXIRI, XELOX) were as follows: Male/female; 32/17, 15/10: Median age; 64(37-80), 65(36-79): Ra/Rb/P; 4/44/1, 0/25/0: T2/T3/T4a/T4b; 4/27/9/10, 0/13/8/4. All pts were underwent R0 resection in both groups. The pathological response (PR) was 30[61.2%] and 17 [68.0%], respectively (p = 0.5669). 31[63.3%] and 14[56.0%] pts achieved down staging, respectively (p = 0.5448). The most common adverse events were as follows; neutropenia (22[44.9%]), leukopenia (14[28.6%]), febrile neutropenia (4[8.2%]) in mFOLFOXIRI and neutropenia (3[12.0%]), thrombocytopenia (1[4.0%]) hand-foot syndrome (1[4.0%]) in XELOX. Conclusion In this study, mFOLFOXIRI and XELOX showed comparable pathological response and favorable R0 resection rate, while XELOX tended to be less toxic. The further investigation is needed.