OBJECTIVETo evaluate the outcome of radical surgery combined with adjuvant radiotherapy for patients aged over 75 years with stage II( or III( rectal cancer.

METHODSFrom 2000 to 2010, 178 patients aged over 75 years at diagnosis who underwent radical surgery in National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, were selected from 3995 patients with stage II( or III( rectal cancer in the database of the above center and enrolled into this retrospective cohort study, which was approved by ethics committee of the above hospital (ClinicalTrials.gov number, NCT02312284).

RESULTSMedian age of patients was 77 years (range 75-87). There were 37 (20.8%), 69 (38.8%), and 72 (40.4%) patients with tumors locating in the high, middle and low rectum respectively; 89(50%) patients of pathological stages II( and III( respectively; 21(11.8%), 137(77%), 19(10.7%), and 1(0.6%) patients with poorly, moderately, well differentiated adenocarcinoma, and mucinous adenocarcinoma respectively. The Charlson/Deyo comorbidity index (CCI) score was 0 in the majority (73.6%) of patients. Fifty-three patients underwent abdominoperineal resection, 116 underwent low anterior resection and 9 underwent Hartmann resection. All the patients received computed tomography-based simulation and treatment planning using an anal marker in a prone or supine position. Patients were treated with linear accelerator by megavoltage photons (6MV), with 2D technique in early years and 3D conformal or simplified intensity-modulated radiotherapy technique later, at a dose of 50 Gy in 25 fractions to the pelvis within an overall treatment time of 35 days. Sixty-one patients (34.3%) received surgery combined with radiation (ART group), in whom 16 received radiation alone 117 patients did not receive radiation(NORT group). The baseline data between ART and NORT group were not significantly different(all P>0.05). There was no significant difference in 5-year overall survival between ART and NORT groups (61.0% vs. 63.0%, P=0.586). The cumulative local relapse was 10.9% and 25.4% in ART and NORT group respectively (P=0.032). Cox multivariate analysis revealed that surgery combined with radiation improved local control significantly(HR=0.27, 95%CI:0.11-0.68, P=0.005).

CONCLUSIONSFor elderly patients aged over 75 years with stage II( or III( rectal cancer, radical surgery combined with radiation does not increase the overall survival, but can improve local control rate. It is reasonable to selectively apply adjuvant radiotherapy to the elderly patients in the setting of radical surgery.