Analysis of the Survival Impact of Postoperative Chemotherapy After Preoperative Chemotherapy and Resection for Gastric Cancer

Background: Perioperative chemotherapy is a standard-of-care treatment for patients with gastric cancer. However, the impact of the postoperative chemotherapy (postCTX) component on overall survival (OS) is not well defined. Methods: The National Cancer Database (NCDB) 2006–2014 was queried for patients who received preoperative chemotherapy (preCTX) and resection for gastric cancer. Analysis was performed to identify factors influencing receipt of postCTX. The impact of postCTX on OS was evaluated in propensity-matched groups. Results: Among 3449 patients who received preCTX and resection for gastric cancer, 1091 (31.6%) received postCTX. Independent predictors of receiving postCTX were diagnosis after 2010 (odds ratio [OR] 1.985), distal tumor location (OR 1.348), and 15 or more lymph nodes examined (OR 1.214). Predictors of not receiving postCTX were older age (OR 0.985), comorbidity score higher than 1 (OR 0.592), and black race (OR 0.791). After propensity-matching (1091 per group), the median OS was 56.8 months for those who did receive postCTX versus 52.5 months for those who did not (p = 0.131). Subset analysis according to tumor grade, lymphovascular invasion, number of lymph nodes evaluated, T and N class, and AJCC stage identified an improvement in OS for the patients with N1 disease who received postCTX compared with those who did not (79.6 vs 41.3 months; p = 0.025). However, no other subgroup had a significant survival benefit. Conclusions: Additional postCTX was administered to a minority of patients who received preCTX and gastrectomy for gastric cancer, and its influence on OS appeared to be limited. Future trials should aim to define patients who will benefit from postCTX.