Long-Term Outcome of Rectal Cancer Patients Treated by High-Dose Radiotherapy and Concurrent Chemotherapy

Abstract

To explore the therapeutic efficacy and adverse effects of high-dose radiotherapy concurrently with chemotherapy in treating patients with non-metastatic rectal cancer. Patients were enrolled if they were diagnosed with stage I-III rectal adenocarcinoma, refused surgery and received high-dose pelvic radiotherapy and concurrent chemotherapy instead. Their clinical data were retrospectively analyzed for calculating local control and survival rates. Treatment related toxicities was evaluated according to the Common Terminology Criteria for Adverse Events (version 5.0). Between April 2006 and February 2021, a total of 93 patients in our medical center were eligible for this study, with a median age of 61 (range, 21-84) years. Of those, 86 (92.5%) patients had tumors located within 5 cm of the anal verge. There were 8 (8.6%), 30 (32.3%) and 55 (59.1%) patients diagnosed with stage I, II and III, respectively. All patients received fluorouracil-based chemotherapy (single-agent fluorouracil or FOLFOX regimen). The irradiation techniques included three-dimensional conformal and intensity-modulated radiation therapy. The median total radiation dose for gross tumor volume (GTV) was 80 (range, 60-90) Gy. The 15 (16.1%) patients refusing surgery before treatment received one course of radiation (60-70 Gy/30-35 Fr). And a 2-course radiation (Course 1, 45-50 Gy/25 Fr; Course 2: 24-40 Gy/12-20 Fr) were given to the 78 (83.9%) patients who failed to achieve clinical complete remission (cCR) after neoadjuvant chemoradiotherapy but still refused surgery, with a median interval of 79 (range, 35-195) days. The median follow-up duration was 66 (range, 10-161) months. The 3- and 5-year overall survival (OS) rates for all patients were 90.5% and 72.7%, respectively. The clinical complete remission rate at the end of chemoradiotherapy was 69.9%. Colostomy was performed in the 14 patients whose rectal tumor did not attain cCR or progressed. There was no grade 4/5 severe acute toxicity. No patient suffered from intestinal perforation. Only one patient developed anal stenosis. Because of rectal bleeding, blood transfusion was performed in 7 patients, and one patient underwent an enterostomy. High-dose radiotherapy concurrent with chemotherapy brought encouraging survival outcomes, satisfactory organ preservation and acceptable short- and long-term side effects. It might be a safe and non-invasive alternative to abdominoperineal resection in rectal cancer patients refusing or unsuitable for surgery, especially for those with a low-position tumor.