Abstract 80P
Background
Short-course radiotherapy (SCRT) has similar overall survival compared to long-course chemoradiotherapy in the neoadjuvant treatment for LARC. However, there wouldn’t be a sufficient time for tumor regression due to the shorter treatment duration of SCRT followed by immediate surgery. This study explores the efficacy of split-Course Hypofraction Radiotherapy (HFRT) combined with CAPOX and Tislelizumab for preoperative treatment of LARC.
Methods
Patients with cT3-4/N1-2 rectal adenocarcinoma received CAPOX combined with Tislelizumab for 6 cycles (3weeks per cycle). 5 fractions of HFRT (7 Gy/fraction) were conducted meanwhile on day 8 per cycle for the first five cycles. Patients underwent TME surgery after a 2-4 week interval after the systematic treatment. The primary endpoint was pCR; the secondary endpoints were 3-year DFS rate, 3-year local recurrence rate, overall survival, R0 rate and safety profile.
Results
By March 1, 2024, 25 patients were enrolled, with a median age of 59 years, Of which 9(36%) patients with T3, 16(64%) with T4 and 18 (72.0%) with N2 staging respectively; 18 (72.0%) patients were microsatellite-stable (MSS). The overall response rate (ORR) was 100%. Of 23 patients went through surgery, 13(56.5%) achieved pCR, 6(26%) and 4 (17.4%) demonstrating TRG1 and TRG2. The R0 rate was 100%. Anterior resection syndrome were reported in three patients. There were no serious adverse events related to the treatment.
Conclusions
To the best of our knowledge, this is the first trial of split-course HFRT combined with chemotherapy and immunotherapy in LARC, showing promising efficacy and safety profiles, warranting further investigation in a larger patient setting.
Clinical trial identification
NCT05176964.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.