Systematic review and meta-analysis of perioperative chemotherapy for gastric cancer patients with microsatellite instability or deficient mismatch repair

The efficacy of perioperative chemotherapy for resectable deficient mismatch repair or microsatellite instablity-high gastric cancer (dMMR/MSI-H GC) is controversial. Researchers of Sichuan University (Chengdu, China) carried out a systematic review and meta-analysis of outcomes after perioperative chemotherapy compared with surgery alone. The analysis included 22 studies, encompassing approximately 1600 patients with dMMR/MSI-H GC. Perioperative chemotherapy did not significantly improve overall survival (HR 0.85; 95% CI 0.58-1.26) and disease-free survival (0.77; 0.53-1.12). In multivariable subgroup analyses, neither neoadjuvant nor adjuvant chemotherapy was associated with improved OS and DFS. Additionally, stage stratification analysis demonstrated no significant survival benefit of adjuvant chemotherapy for stage II of stage III disease. The authors conclude that perioperative chemotherapy does not significantly improve OS or DFS in dMMR/MSI-H GC.