The optimal care for pT3N0 rectal cancer remains controversial. And whether tumor location can be used to guide the administration of adjuvant radiotherapy for pT3N0 rectal cancer is not fully confirmed. The current study was designed to identify the benefit of adjuvant radiotherapy for pT3N0 rectal cancer.

We performed a retrospective study of 265 pT3N0 rectal cancer patients who were treated by surgery and adjuvant therapy from Mar. 2005 to Sept. 2015. All patients were divided into two groups according to receiving adjuvant radiotherapy or not. Overall survival (OS), disease-free survival (DFS) were compare between patients who did and did not receive adjuvant radiotherapy. Multivariate analysis was performed to explore clinical factors significantly associated with DFS, local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS).

For patients with lower tumor, DFS in adjuvant chemo-radiotherapy group was higher than that in adjuvant chemotherapy group. Besides, the rates of local recurrence and distant metastasis were found lower in patients who did receive adjuvant radiotherapy than those who did not. For patients with upper tumor, the 5-year OS and DFS were similar between groups of adjuvant chemotherapy and adjuvant chemo-radiotherapy. Multivariable analysis indicated both the CEA and tumor location were independent predictors of LRFS. And adjuvant radiotherapy predicted the DFS, LRFS and DMFS in lower rectal cancer patients.

Tumor location can serve as an indication for the administration of adjuvant radiotherapy in pT3N0 rectal cancer patients.