Neoadjuvant radiotherapy for locoregional Siewert type II gastroesophageal junction adenocarcinoma: A propensity scores matching analysis

OBJECTIVE: To analyze the effect of neoadjuvant radiotherapy (nRT) on prognosis in patients with locoregional Siewert type II gastroesophageal junction adenocarcinoma (GEA). METHOD: All patients pathologically diagnosed as Siewert type II GEA between 2004 and 2015 were retrieved from the Surveillance, Epidemiology and Final Results (SEER) database. We analyzed the impact of different treatment regimens on the prognosis in each stage. Survival analysis was performed by Kaplan-Meier (K-M) method. Multivariate Cox model and propensity score matching was further used to verify the results. RESULTS: 4,160 patients were included in this study. The efficacy of nRT was superior to that of adjuvant radiotherapy (aRT) (p = 0.048), which was the same as that of surgery combined with chemotherapy (p = 0.836), but inferior to the overall survival (OS) of surgical treatment alone (p<0.001) in T1-2N0M0 patients. Patients receiving nRT had distinctly better survival than those receiving surgical treatment alone (p = 0.008), but had similar survival compared with patients treated with aRT (p = 0.989) or surgery combined with chemotherapy (p = 0.205) in the T3N0/T1-3N+M0 subgroup. The efficacy of nRT is clearly stronger than that of surgical therapy alone (p<0.001), surgery combined with chemotherapy (p<0.001), and aRT (p = 0.008) in patients with T4 stage. The survival analysis results were consistent before and after propensity score matching. CONCLUSION: In these carefully selected patients, the present study made the following recommendations: nRT can improve the prognosis of patients with T3N0M0/T1-3N+M0 and T4 Siewert type II GEA, and it seems to be a better treatment for T4 patients. Surgery alone seems to be sufficient, and nRT is not conducive to prolonging the survival of Siewert II GEA patients with T1-2N0M0 stage. Of course, further prospective trials are needed to verify this conclusion.