A phase II trial of total neoadjuvant treatment (TNT) (Capox plus radiotherapy) for local advanced rectal cancer patients with high risk factors.

Abstract

e15025 Background: Standard neoadjuvant concurrent chemoradiotherapy didn't achieve improved overall survival in stage II-III rectal cancer. Total neoadjuvant treatment (TNT) might be a proper treatment option for patients with high risk factors. Therefore, this phase II trial was conducted to evaluate the safety and efficacy of TNT (Capox and IMRT/VMAT) in rectal cancer patients with high risk factors. Methods:Patients who were diagnosed stage II-III rectal cancer with at least one of the following high risk factors were recruited: cT4b, cN2, EMVI +, MRF+, lateral LN +. Three cycles of induction Capox were followed by pelvic IMRT/VMAT and two cycles of concurrent Capox. Three cycles of consolidation Capox were delivered after radiotherapy. Primary endpoints were pathological complete response (pCR) and R0 resection rate. Secondary endpoints were DFS, OS, toxicities and QOL. Here we present the initial results of this study. Results: From Jun 2015 to Jan 2017, 42 patients were evaluable. One patient (2.4%) who had acute intestinal obstruction after the first cycle of chemotheraoy underwent emergency TME. A total of 27 patients (64.3%) completed 8 cycles of chemotherapy. Forty-one patients (97.6%) completed the planned radiotherapy. 15 of 42 patients (35.7%) achieved a pCR or cCR, in which 12 patients (80%) completed 8 cycles of chemotherapy. Five patients refused the operation and selected Watch & Wait. R0 resection rate of patients who underwent TME were 100%. The mean time of operation was 207 minutes (120-370 minutes). And the mean estimated blood loss was 89ml (10-500ml). The most common grade 3 or higher adverse events associated with the neoadjuvant administration were leucopenia (9.5%), diarrhea (4.8%), radiation dermatitis (4.8%) and thrombocytopenia (2.4%). The most common grade 3 or worse surgery-related complications were pelvic abscesses, anastomotic leaks and hemorrhage which were observed in one patient, respectively. Conclusions: Total neoadjuvant treatment (TNT) is effective and safe for local advanced rectal cancer patients with high risk factors. Long-term efficacies of TNT need to be evaluated.