Significance of postoperative radiotherapy for stage II/III upper rectal cancer

Objective To investigate the value of postoperative adjuvant chemoradiotherapy (CRT) in the treatment of stage Ⅱ/Ⅲ upper rectal cancer. Methods A total of 3995 patients with rectal cancer were admitted to our hospital from 2000 to 2010. Among them, patients who were pathologically diagnosed with adenocarcinoma and underwent radical surgery were enrolled as subjects for retrospective analyses. Moreover, all selected patients had the lower margin of the tumor located within 10-16 cm from the anal verge, as determined by a colonofiberscope before surgery, and were pathologically staged as T3-4 or N0-2 M0 after surgery, according to the 7 th edition of American Joint Committee on Cancer tumor-node-metastasis staging system. Results A total of 547 patients were enrolled as subjects. The 5-year sample size was 249. In all patients, the 5-year overall survival (OS), disease-free survival, local recurrence-free survival (LRFS) , and distant metastasis-free survival rates were 79.0%, 76.8%, 94.0%, and 80.1%, respectively. One hundred and fifty-five patients were enrolled into either postoperative concurrent CRT group or postoperative non-CRT group, with the baseline characteristics balanced between the two groups by the propensity-score matching method (1:1). Patients who were staged as pT4b and had paracancerous nodules and lymph node metastases (stage N2) were enrolled into high-risk group. In the high-risk group, patients treated with postoperative CRT had significantly higher LRFS and OS rates than those treated with only surgery (96.3% vs. 82.0%, P = 0. 044; 81.6% vs. 59.1%, P=0.019). Conclusions Radical surgery achieves a good prognosis in patients with stage Ⅱ/Ⅲ upper rectal cancer, and postoperative CRT can further reduce the locoregional recurrence rate. Particularly, postoperative CRT/RT can substantially improve local and long-term outcomes in patients with high-risk factors. Key words: Upper rectal neoplasms/surgery; Upper rectal neoplasms/postoperative radiotherapy; Prognosis analysis