Treatment trends and predictors of adjuvant and neoadjuvant therapy for gastric adenocarcinoma in the United States

Purpose: Over the last decade, evidence suggesting the benefits of adjuvant therapy in the treatment of stage IB-III gastric adenocarcinoma has emerged, though the influence of these clinical trials and current treatment patterns is unknown. Our objectives were (1) to assess changes in gastric adenocarcinoma treatment over time, (2) to identify predictors of neoadjuvant or postoperative adjuvant therapy use, and (3) to identify factors associated with neoadjuvant therapy use. Methods: Patients with stage IB-III gastric adenocarcinoma diagnosed between 1998 and 2007 in the National Cancer Data Base who underwent surgical resection were selected. Models were developed to identify factors associated with treatment. Results: We identified 30,448 patients diagnosed with stage IB-III gastric adenocarcinoma who underwent surgical resection. Rates of systemic therapy receipt (either before or after surgery) increased by 71 % from 1998 to 2007 (p < 0.001). Receipt of neoadjuvant therapy receipt increased by 237 % over 10 years (p < 0.001), with the highest rate of increase seen at high-volume academic centers. American Joint Committee on Cancer (AJCC) stage and age were the strongest predictors of pre- or postoperative systemic therapy among surgical patients. Neoadjuvant therapy receipt was most strongly predicted by tumor location in the gastric cardia. Conclusions: Treatment trends over the past decade reflect rapid adoption of evidence from randomized controlled trials by increased receipt of pre- and postoperative systemic therapy in the treatment of stage IB-III gastric adenocarcinoma. Although age and AJCC stage are strongly associated with receiving systemic adjuvant therapy, tumor location is the most significant predictor of neoadjuvant therapy.