Efficacy of Dose-Escalated Radiotherapy for Recurrent Colorectal Cancer

Purpose: This study aimed to evaluate the effects of radiotherapy (RT) on progression-free survival (PFS) for patients with recurrent colorectal cancer. Methods: We reviewed the records of 22 patients with recurrent colorectal cancer treated with RT between 2008 and 2014. The median radiation dose for recurrent disease was 57.6 Gy (range, 45-75.6 Gy). Patients were divided into 2 groups according to the type of RT: patients underwent RT without previous history of irradiation (n = 14) and those treated with secondary RT (reirradiation: n = 8) at the time of recurrence. Results: The median follow-up period was 24.9 months (range, 4.5-66.6 months). Progression was observed in 14 patients (including 8 with loco-regional failure and 9 with distant metastases). Distant metastases were related to the RT dose (<70 Gy, P = 0.031). The 2-year loco-regional control (LRC), PFS, and overall survival (OS) rates were 74.6%, 45.1%, and 82.0%, respectively. The LRC rate was not different between the patients treated with RT for the first time and those treated with reirradiation (P = 0.101, 2-year LRC 79.5% vs. 41.7%). However, reirradiation was related to poor PFS (P = 0.022) and OS (P = 0.002). An escalated RT dose (>= 70 Gy) was associated with a higher PFS (P = 0.014, 2-year PFS 63.5% vs. 20.8%). Conclusion: Salvage RT for locally recurrent colorectal cancer can be offered when surgery is impossible. Dose-escalated RT shows a possible benefit in reducing the risk of progression.