Key clinical point: Microsatellite instability (MSI)-high locally advanced gastric cancer is less likely to display a pathologic response to chemotherapy but is associated with better survival than microsatellite-stable (MSS) cancer.
Major finding: In patients treated with chemotherapy, MSI-high vs MSS tumors were associated with a significantly better overall survival (adjusted hazard ratio [aHR] 0.53; P = .047) and disease-specific survival (aHR 0.24; P = .002) and a lower pathological chemotherapy response rate (0% vs 16%; P < .001).
Study details: This retrospective cohort study included 535 patients with primary, locally advanced gastric cancer who underwent surgery alone or in conjunction with neoadjuvant, perioperative, or adjuvant chemotherapy, of which 82 patients had an MSI-high tumor.
Disclosures: This study was supported by a US National Cancer Institute Cancer Center Support Grant. The authors declared no conflicts of interest.
Source: Vos EL et al. Survival of locally advanced MSI-high gastric cancer patients treated with perioperative chemotherapy: A retrospective cohort study. Ann Surg. 2022 (Jun 29). Doi: 10.1097/SLA.0000000000005501