The addition of chemoradiation to adjuvant chemotherapy is associated with improved survival in lymph node-positive gastric cancer

Background: In the ARTIST trial, chemoradiation did not improve disease-free survival (DFS) in gastric cancer patients treated with curative-intent surgery and adjuvant chemotherapy. Subgroup analysis suggested chemoradiation improved DFS in patients with lymph node (LN) metastases, but the role of adjuvant chemoradiation remains uncertain. This study sought to determine the role of adjuvant chemoradiation using population-based methods. Methods: Surveillance, Epidemiology and End Results-Medicare linked data from 2004 to 2013 was used to identify patients aged 66 and older with LN-positive gastric adenocarcinoma. Multivariable logistic regression evaluated factors associated with receipt of chemoradiation. The Kaplan-Meier method and Cox proportional hazards modeling were used to evaluate overall survival (OS). Results: A total of 2409 patients with LN-positive gastric adenocarcinoma who underwent upfront surgical resection were identified; 309 (13%) received adjuvant chemotherapy and 407 (17%) received adjuvant chemotherapy and chemoradiation. Among all patients, median OS was 15 months. Median OS was 20 months for patients who received chemotherapy alone and 27 months for patients who received chemotherapy and chemoradiation (p < 0.05). Recent diagnosis, older age, tumor stage T3 or T4, and Charleston Comorbidity Index were associated with an increased hazard ratio for death (p < 0.05). Receipt of chemoradiation was associated with a decreased hazard ratio for death (p < 0.05). Conclusions: In patients with LN-positive gastric adenocarcinoma, the addition of chemoradiation to adjuvant chemotherapy after upfront surgical resection was associated with improved survival irrespective of the extent of lymphadenectomy. These data suggest chemoradiation should be considered in patients with LN-positive gastric adenocarcinoma.