Identifying the long-term survival beneficiary of preoperative radiotherapy for rectal cancer in the TME era

Abstract

This study was to verify the long-term survival efficacy of preoperative radiotherapy (preRT) for locally advanced rectal cancer (LARC) patients and identify potential long-term survival beneficiary. Using the Surveillance, Epidemiology, and End Results (SEER) database, 7582 LARC patients were eligible for this study between 2011 and 2015 including 6066 received preRT and 1516 received surgery alone. Initial results showed that preRT prolonged the median overall survival (OS) of LARC patients (HR 0.86, 95% CI 0.75–0.98, P < 0.05), and subgroup analysis revealed that patients with age > 65 years, stage III, T3, T4, N2, tumor size > 5 cm, tumor deposits, and lymph nodes dissection (LND) ≥ 12 would benefit more from preRT (all P < 0.05). A prognostic predicting nomogram was constructed using the independent risk factors of OS identified by multivariate Cox analysis (all P < 0.05), which exhibited better prediction of OS than the 8th American Joint Cancer Committee staging system on colorectal cancer. According to the current nomogram, patients in the high-risk subgroup had a shorter median OS than low-risk subgroup (HR 2.62, 95% CI 2.25–3.04, P < 0.001), and preRT could benefit more high-risk patients rather than low-risk patients. Hence, we concluded that preRT might bring long-term survival benefits to LARC patients, especially those with high risk.