The Stage Migration Should be Reconsidered in Stage IIIA Rectal Cancer: Based on Propensity Score Analysis

Background: Few studies have compared the survival outcomes of stages II and IIIA rectal cancer patients who did not receive neoadjuvant treatment. This study aimed to compare oncologic outcomes between 2 groups. Patients and Methods: This study analyzed stage II or IIIA rectal cancer patients who underwent radical operation without neoadjuvant treatment between 1996 and 2013. The 3:1 propensity score analysis was used to adjust for several variables. After propensity score matching, 364 stage II rectal cancer, and 172 stage IIIA rectal cancer patients were analyzed. Results: There were no significant differences in 5-year overall survival or disease-free survival rates between the 2 groups. When stage II rectal cancer was subdivided into stages IIA, IIB, and IIC, the 5-year DFS and OS rates of stage IIIA rectal cancer patients were similar to those of stage IIA cancer patients. Moreover, stage IIIA rectal cancer patients showed a statistically significantly better survival rates than stage IIC rectal cancer patients. Conclusion: Stage IIIA group showed similar survival outcomes compared to stage IIA and IIB group and significantly better outcomes than stage IIC group. Thus, it should be considered to classify stage IIIA as a subgroup of stage II rather than as a subgroup of stage III rectal cancer. It should be also be considered to change to determine whether to do adjuvant treatment according to stage II rectal cancer.