Outcomes of radiation therapy for resectable M0 gastric cancer.

Background: The role of radiaotion therapy in resectable gastric cancer patients without distant metastases remains controversial. This retrospective analysis was performed to identify whether resectable gastric cancer patients without distant metastases might benefit from radiation. Results: The results of the Kaplan-Meier analysis and log-rank test showed that a total of 3309 patients had a MST of 29.0 months, a 1-year survival rate of 74.7%, and a 3-year survival rate of 45.5%. Among them, the MST of the "RPS" group and the "RAS" group were significantly longer compared with that of the "No Radiation" group (32.7vs 32.9 vs 25.3 months, P < 0.05). The 1-year survival rates were 83.7%, 83.5% and 65.6% for the "RPS", "RAS" and "No radiation" groups, respectively (P < 0.05) and the 3-year survival rates were 52.6%, 63.6% and 44.9%, respectively (P < 0.05). The multivariate Cox proportional hazard regression analysis showed that radiation was an independent prognostic factor. Materials and Methods: A total of 5744 patients from the SEER database who were initially diagnosed with histologically confirmed gastric cancer without distant metastases from 2010 to 2013 were included. Patients were divided into three groups as follows: patients who underwent radiation after surgery ("RAS" group), patients who underwent radiation prior to surgery ("RPS" group) and patients who did not undergo radiation, only surgery performed ("No radiation'" group). Conclusions: This retrospective analysis demonstrated that "RPS" or "RAS" alone were independent prognostic factors for survival improvement in selected gastric cancer patients without distant metastases.