Survival of Locally Advanced MSI-high Gastric Cancer Patients Treated With Perioperative Chemotherapy: A Retrospective Cohort Study. Issue 5 (29th May 2023)

• Record Type: Journal Article
• Authors: Vos, Elvira L.; Maron, Steven B.; Krell, Robert W.; Nakauchi, Masaya; Fiasconaro, Megan; Capanu, Marinela; Walch, Henry S.; Chatila, Walid K.; Schultz, Nikolaus; Ilson, David H.; Janjigian, Yelena Y.; Ku, Geoffrey Y.; Yoon, Sam S.; Coit, Daniel G.; Vanderbilt, Chad M.; Tang, Laura H.; Strong, Vivian E.
• Is Part Of: Annals of surgery. Volume 277:Issue 5(2023)
• Page Start: 798
• Page End: 805
• Publication Date: 2023-05-29
• Subjects: microsatellite instability -- mismatch repair defect -- neoadjuvant chemotherapy -- gastric cancer -- gastric adenocarcinoma -- immunotherapy; Surgery -- Periodicals; 617.005
• DOI: 10.1097/SLA.0000000000005501
• Languages: English
• ISSNs: 0003-4932

Abstract

Abstract : Objective: To evaluate the efficacy of chemotherapy in patients with microsatellite instability (MSI)-high gastric cancer. Background: Although MSI-high gastric cancer is associated with a superior prognosis, recent studies question the benefit of perioperative chemotherapy in this population. Methods: Locally advanced gastric adenocarcinoma patients who either underwent surgery alone or also received neoadjuvant, perioperative, or adjuvant chemotherapy between 2000 and 2018 were eligible. MSI status, determined by next-generation sequencing or mismatch repair protein immunohistochemistry, was determined in 535 patients. Associations among MSI status, chemotherapy administration, overall survival (OS), disease-specific survival, and disease-free survival were assessed. Results: In 535 patients, 82 (15.3%) had an MSI-high tumor and ∼20% better OS, disease-specific survival, and disease-free survival. Grade 1 (90%–100%) pathological response to neoadjuvant chemotherapy was found in 0 of 40 (0%) MSI-high tumors versus 43 of 274 (16%) MSS. In the MSI-high group, the 3-year OS rate was 79% with chemotherapy versus 88% with surgery alone ( P =0.48). In the MSS group, this was 61% versus 59%, respectively ( P =0.96). After multivariable interaction analyses, patients with MSI-high tumors had superior survival compared with patients with MSS tumors whether given chemotherapy (hazard ratio=0.53, 95% confidence interval: 0.28–0.99) or treated with surgery alone (hazard ratio=0.15, 95% confidence interval: 0.02–1.17). Conclusions: MSI-high locally advanced gastric cancer was associated with superior survival compared with MSS overall, despite worse pathological chemotherapy response. In patients with MSI-high gastric cancer who received chemotherapy, the survival rate was ∼9% worse compared with surgery alone, but chemotherapy was not significantly associated with survival.