Altman, Ariella2019-09-172019-09-172019-07https://hdl.handle.net/11299/206715University of Minnesota M.S. thesis.July 2019. Major: Clinical Research. Advisor: Todd Tuttle. 1 computer file (PDF); vii, 30 pages.Background: Adjuvant therapies improve survival in gastric cancer; however, the role of adjuvant chemoradiation in the treatment of lymph node (LN)-positive gastric cancer remains uncertain. This study sought to determine the role of adjuvant chemoradiation in addition to chemotherapy after resection for lymph node positive gastric cancer. Methods: The Surveillance, Epidemiology and End Results-Medicare linked data from 2004-2013 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 2,409 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.enChemotherapyGastric CancerRadiationThesis or Dissertation