Immediate Results of a Prolonged Course of Neoadjuvant Chemoradiotherapy for Patients with Locally Advanced Rectal Cancer: a Comparison of Classical and Hypofractional Regimes

Abstract

Purpose: To compare the effectiveness of the hypofractional and classical modes of radiation therapy in a neoadjuvant prolonged course of chemoradiotherapy for patients with locally advanced rectal cancer (LARC). Material and methods: This work is based on a retrospective analysis of the database of patients with LARC, who from 2013 to 2017 underwent a prolonged course of neoadjuvant chemoradiotherapy with subsequent surgical intervention. Patients were divided into two groups: the first (main) group, 71 patients with LARC, who, as part of the neoadjuvant treatment, underwent a course of chemoradiotherapy (CRT) in the hypofractionation mode (4 Gy, 3 fractions per week, 32 Gy to regional lymph nodes pelvis and up to 40 Gy to the primary tumor) in combination with chemotherapy with capecitabine 1650 mg/m2 in two doses daily on weekdays. The second group (control group) included 79 patients with LARC, who underwent CRT in the classical fractionation regimen (2 Gy, 5 fractions per week, 44 Gy to regional pelvic lymph nodes and up to 50–58 Gy to the primary tumor) in combination with capecitabine chemotherapy 1650 mg/m2 in two doses on the days of radiation therapy. Results: The average duration of a prolonged course of CRT in the main group was 22.56 (95 % CI from 21.94 to 23.18) calendar days, in the control group — 38.84 (95 % CI from 38.12 to 39.54), p = 0.0001. Pathological response of the III degree in the main group was recorded in 23 % of cases, and of the IV degree in 18 %, in the control group these indicators were 19 % and 15 %, respectively, p = 0.4. A decrease in the stage of the tumor process was recorded in 50 (70.4 %) cases in the main group and in 47 (59.5 %) cases in the control group, p = 0.16. No statistically significant differences were observed in the incidence and severity of cases of hematological and local toxicity. Conclusion: The results of our study confirm that the use of a prolonged course of neoadjuvant chemoradiotherapy in hypofractionation mode does not worsen oncological results, does not increase the frequency and severity of early and late radiation injuries, but at the same time reduces the duration of the course of treatment by two weeks. The hypofractionation regimen can be considered as an alternative and not inferior to the classical regimen in the neoadjuvant course of CRT of patients with LARC.