Abstract
PURPOSE: The treatment of gastric adenocarcinoma (GA) continues to evolve. While neoadjuvant chemotherapy (NAC) has demonstrated emerging benefit, the optimal treatment regimen, and sequence remain to be firmly established. METHODS: Patients with nonmetastatic GA who underwent resection were identified within the 2020 National Cancer Database. Patients were compared between the mutually exclusive treatment groups of NAC, neoadjuvant chemoradiotherapy (NCRT), adjuvant chemotherapy, adjuvant chemoradiotherapy (CRT), and surgery only. The primary endpoint was receipt of NAC or NCRT. Patients were 1-to-1 propensity score matched for receiving any neoadjuvant therapy. Multivariable logistic regression was used to identify predictors of receipt of any neoadjuvant therapy and receipt of any adjuvant therapy. RESULTS: Twenty-five thousand and seventy-three patients were included in the analysis. Patients were treated with NAC (25.0%), NCRT (31.4%), adjuvant chemotherapy (6.5%), adjuvant CRT (12.6%), and surgery only (24.5%). Compared to 2006-2011, patients diagnosed between 2012 and 2017 experienced the greatest increases in NAC (18.6% vs. 29.0%; p < 0.001) and NCRT (25.0% vs. 35.5%; p < 0.001). Median OS was 44.9 months. OS was longest for patients who received any neoadjuvant therapy compared to those receiving adjuvant or surgery only (51.0 vs. 42.4 vs. 38.0 months, respectively; p < 0.001). Patients who were Black, in the lowest income quartile or treated at lower volume facilities were less likely to receive NAT (all p < 0.001). CONCLUSIONS: There has been significant acceleration in the use of neoadjuvant therapy for GA. Currently, NCRT followed by surgery are the most common treatment sequences in the United States. Additional trials are needed to further define the optimal treatment sequence.