Comparison of 5-Year Oncological Outcomes of Locally Advanced Rectal Cancer Patients Treated with Radiotherapy versus Without Radiotherapy: A Real-World Single-Center Retrospective Study

Mookda Nivaarrarsuwonnakul

doi:10.64387/tjs.2026.276741

Authors

Mookda Nivaarrarsuwonnakul Division of Surgery, Trang Hospital, Trang

DOI:

https://doi.org/10.64387/tjs.2026.276741

Keywords:

Rectal cancer, Omission of radiotherapy, Long-term outcome

Abstract

Background and Objective: Most oncologists treat rectal cancer following NCCN guidelines. Chemoradiotherapy (RT) is preferred for patients with suspected or proven T3-4 disease and/or regional node involvement. RT may result in tumor shrinking, reduce risk of local recurrence in the pelvis, and has been standard of care in North America for locally advanced rectal cancer. Because access to radiation is limited in Thailand, half of the patients deny being referred to radiation centers due to long waiting times and expenses. A transabdominal resection without radiotherapy (RT) was inevitable, but it observed favorable results. This study aimed to compare the long-term oncological outcomes of locally advanced rectal cancer patients who received RT with those who did not receive RT.

Materials and Methods: This retrospective study reviewed data of patients with clinical stage T3-4 rectal cancer who underwent curative resection, received RT, and those without RT from 1 January 2014 to 31 December 2019 in Trang Hospital. The survival and disease status of patients were updated as of 31 July 2024.

Results: Of 54 rectal cancer patients who underwent curative transabdominal resection (mean age 61.57 ± 10.8 years, male 51.9%), 26 patients (48.1%) received RT, and 28 patients (51.9%) did not receive RT. The median follow-up time was 68.5 months (range, 5-113 months). There was no statistical difference between the RT group and the no RT group in 5-year disease-free survival (72.1% vs.88.5%; P = 0.320) and 5-year overall survival rates (68.8% vs. 82.1%; P = 0.242). The 5-year local recurrence rate was higher in the RT group, but there was no statistically significant difference (21.7% vs. 4.0%; P = 0.147).

Conclusion: In rectal cancer patients who were eligible for curative transabdominal resection, receiving or not receiving RT offered comparable long-term oncological outcomes. Omitting RT is an option when radiotherapy is unavailable.

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