81P - Concurrent or consolidation chemotherapy during radiation as neoadjuvant treatment for locally advanced rectal cancer: A propensity score analysis from two prospective study

Abstract

BackgroundmFOLFOX6 concurrent radiotherapy in the FOWARC study led to 27% of pCR rate in locally advanced rectal cancer (LARC). The total neoadjuvant treatment study (CAO/ARO/AIO-12) had compared the efficacy of chemoradiotherapy plus induction or consolidation chemotherapy. The result showed that consolidation chemotherapy led to higher pCR rate than that of induction chemotherapy. Here, we aimed to compare the efficacy of preoperative concurrent mFOLFOX6 chemoradiotherapy versus concurrent and consolidation chemotherapy during radiation as neoadjuvant treatment in locally advanced rectal cancer. MethodsProspectively maintained databases of patients from two clinical trials ( NCT01211210 and NCT02217020) underwent preoperative treatment for locally advanced rectal cancer were included. 143 patients received concurrent mFOLFOX6 chemoradiotherapy and TME surgery. 123 patients received concurrent and consolidation chemotherapy during radiation before TME. A comparative analysis was performed after the implementation of propensity score matching on the 2 main cohorts. ResultsA total of 266 patients were enrolled in the study. After propensity score matching, 180 patients were selected. 113 patients were comparable in the two groups. The pathologic complete response rate was comparable between the two groups (27.1% vs. 27.9%). And the tumor downstaging rate was also similar between the two groups (54.1vs. 59.1%). The compliance of chemotherapy was much better in concurrent chemoradiotherapy with mFOLFOX6 (93.5% vs. 39.5%). Higher incidence of grade 3/4neutropenia (16.1% vs. 30.1%, P < 0.01) was shown in concurrent chemoradiotherapy group than that of concurrent and consolidation chemoradiotherapy group. ConclusionsPreoperative concurrent chemoradiotherapy with mFOLFOX6 showed similar efficacy with radiotherapy plus consolidation chemotherapy and higher compliance of chemotherapy. Long-term follow-up will assess whether the higher compliance would translates to better oncologic outcome. Legal entity responsible for the studyYanhong Deng. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.