Association of Adjuvant Chemotherapy with Overall Survival among Patients with Locally Advanced Gastric Cancer after Neoadjuvant Chemotherapy

Abstract

Importance: Neoadjuvant chemotherapy (NAC) is a standard treatment option for locally advanced gastric cancer (LAGC); however, the indications for adjuvant chemotherapy (AC) in patients with LAGC who received NAC remain controversial. Objective: To compare survival rates between patients with LAGC who received AC and those who did not after NAC followed by surgery. Design, Setting, and Participants: This multicenter, international cohort study included 353 patients with LAGC undergoing curative-intent gastrectomy after NAC at 2 tertiary referral teaching hospitals in China between June 1, 2008, and December 31, 2017. To externally validate the findings in the Chinese patients, 109 patients from the US and Italy between June 1, 2006, and June 30, 2013, were reviewed. The follow-up period of the Chinese patients was completed in December 2020, and the follow-up period of the Western patients was completed between February and July 2017. Data analysis was performed from December 1, 2020, to February 28, 2021. Exposures: Patients who received AC and those who did not were propensity score matched to evaluate the association of AC with survival. Main Outcomes and Measures: Overall survival (OS), disease-free survival, and disease-specific survival. Results: Of 353 patients from China (275 [78.1%] male; mean [SD] age, 58.0 [10.7] years), 262 (74.1%) received AC and 91 (25.9%) did not. After propensity score matching, the 3-year OS was significantly higher in patients who received AC (60.1%; 95% CI, 53.1%-68.1%) than in those who did not (49.3%; 95% CI, 39.8%-61.0%) (P =.02). Lymph node ratio (LNR) was significantly associated with AC benefit (P