Proton radiotherapy for rectal cancer

Abstract

AIM: to assess the effectiveness of proton radiotherapy as part of a combined approach to the treatment of rectal malignancies and to assess acute radiation toxicity, which directly affects patients’ quality of life.PATIENTS AND METHODS: between 2020 and 2023, a study included 74 patients with rectal cancer. The mean age of the patients was 65 ± 9.9 years, 44 (60%) males. Stage I occurred in 8 (10.8%) patients, stage II — in 14 (18.9%) patients, stage III — in 52 (70.3%) patients. At the first stage, all patients completed proton radiation therapy in the classical fractionation mode.RESULTS: of the adverse events, 49 (66%) patients had grade 1–2 radiation reactions in the form of proctitis and cystitis. There were no local radiation reactions of grade 3 or higher. Systemic complications of grade 3 were noted in 2 (2%) patients in the form of hematological toxicity — anemia (1%), afebrile neutropenia (2%). Of the 62 operated patients, 12 (19.3%) people showed complete therapeutic pathomorphosis. With a median follow-up of 23 months (13;35), 1 (1.35%) patient showed continued tumor growth 28 months after completed radiotherapy, 2 (2.7%) patients had local recurrence 3 and 18 months after treatment. Distant metastases to the lungs, liver, or bones were detected in 9 (12.2%) patients, median — 12 months (6;23). Mortality during the entire observation period was 9 (12.2%) patients. Sixty-two (83.8%) patients showed no signs of relapse or progression of the disease, of which 9 (14.5%) patients did not receive any treatment after chemoradiotherapy and are in the process of active follow-up.CONCLUSION: proton radiation therapy in patients with rectal cancer in two-year overall survival (90.5%) and progression-free survival (88.9%) are comparable with the literature data of recent studies, but are superior in overall survival pathological response (19.3%).