Clinical impact of underutilization of adjuvant therapy in node positive gastric adenocarcinoma

Background: Adjuvant therapy for gastric adenocarcinoma has shown a survival advantage, though it may be underutilized. The purpose of this study is to examine how infrequently adjuvant therapy is administered with curative intent gastrectomy for node positive gastric cancer and the long-term effects to patients. Methods: The National Cancer Database was queried from 2006-2013 for patients with node positive gastric adenocarcinoma undergoing a potentially curative gastrectomy. Overall survival was compared between patients who received adjuvant chemotherapy or chemoradiation and those who did not. Results: Of 2,565 patients, 793 (30.9%) patients did not receive any adjuvant chemotherapy or radiation therapy, while 147 (5.7%) received peri-operative chemotherapy and 723 (28.2%) received post-operative chemoradiation. From 2006-2013, the percentage of patients receiving peri-operative chemotherapy rose from 1.1% to 9.9%, while those receiving post-operative chemoradiation decreased from 39.7% to 21.6%. The adjusted restricted mean survival time over 5 years for no adjuvant therapy was 27.7 months, perioperative chemotherapy was 39.6 months, and post-operative chemoradiation was 37.7 months (P<0.0001). Conclusions: Approximately one third of patients treated for node positive gastric cancer undergo surgical resection without adjuvant therapy. This is associated with poorer survival, highlighting the need for improvement in multimodality care and cancer outcomes.