119P - Neoadjuvant chemoradiotherapy in the mode of hypofractionation in locally advanced rectal cancer: Is it time to change standards of care?

Background

To conduct a comparative analysis of the effectiveness of hypofractional and classical radiotherapy regimens in neoadjuvant chemoradiotherapy for locally advanced rectal cancer (LARC).

Methods

This study based on a retrospective analysis of a database in patients with LARC who underwent a course of neoadjuvant chemoradiotherapy followed by surgery. The patients were divided into two groups: the first (main) group, 104 patients who underwent a course of hypofractionated chemotherapy (4 Gy x 40 Gy 3 fractions per week) in combination with capecitabine 1650 mg/m2 in two doses. The second group (control group) included 120 patients who underwent a course of CRT in the classical fractionation regimen (2 Gy x 50-58 Gy 5 fractions per week) in combination with capecitabine 1650 mg/m2 in two doses. The main evaluated indicators are the frequency of pCR and cCR. Additional assessed indicators are the severity of early radiation toxicity, the frequency of local relapses, overall and disease-free survival.

Results

The study included 224 patients. The average duration of the CRT course in the study group was 22.56 (95% CI from 21.94 to 23.18) days, in the control group - 38.84 (95% CI from 38.12 to 39.54), p=0.0001. Radiation toxicity grade III and IV was registered in 5.75% of patients in the study group and in 6.41% of patients in the control group. pCR in the study groups was achieved in 19.23% and 15.83% of cases, respectively, p=0.504. The cCR in the studied groups was achieved in 25% and 18.3% of cases, respectively, p=0.226. The median time without progression was 37.6 months. In the main and control groups, local control rates were 91.34% and 88.3% respectively, p=0.954, HR=1.05 (95% CI 0.21 to 5.22). Five-year disease-free survival in the main group was 71.1% and in the control group 60.8%, respectively, p=0.353, HR=0.79 (95% CI 0.42 to 1.35). Five-year overall survival in the main and control groups were 81.7% and 79.2%, respectively, p=0.743, HR=0.87 (95% CI 0.39 to 1.92).

Conclusions

Thus, the hypofractionation regimen showed high antitumor efficacy and can be considered as an alternative and not inferior to the classical regimen in neoadjuvant CRT in patients with LARC.

Clinical trial identification

N/A

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.