Does combining chemotherapy and immune checkpoint inhibitors improve response in gastric adenocarcinoma?
Combining immune checkpoint inhibitors (ICIs, drugs that help the immune system attack cancer cells) with chemotherapy does improve response rates in gastric adenocarcinoma, especially the rate of pathological complete response (pCR, meaning no cancer cells remain in the removed tissue after treatment). A large meta-analysis of 74 trials found that ICI plus chemotherapy roughly tripled the pCR rate compared to chemotherapy alone 2. However, improved response does not always translate into longer survival, and the benefit varies by treatment setting and patient subgroup 28.
What the research says
The strongest evidence comes from a 2026 meta-analysis of 74 trials, including 16 randomized controlled trials (RCTs) and 58 prospective single-arm trials, that looked at ICI-based treatments given before surgery for locally advanced resectable gastric or gastroesophageal junction adenocarcinoma. In randomized comparisons, ICI plus chemotherapy was linked to a much higher pCR rate (risk ratio 3.01, 95% CI 2.19-4.15) and major pathological response rate (risk ratio 1.59, 95% CI 1.36-1.85). In perioperative trials, there was also an overall survival benefit (hazard ratio 0.81, 95% CI 0.70-0.93) 2. A separate 2024 meta-analysis of five RCTs with 2,718 patients found that adding ICIs to perioperative chemotherapy significantly improved pCR rates (odds ratio 3.43, 95% CI 2.61-4.50) but did not significantly change R0 resection rates or D2 lymphadenectomy rates 11.
What to ask your doctor
- Does my specific cancer type and stage make me a good candidate for combining immunotherapy with chemotherapy?
- What does a pathological complete response mean for my long-term outlook, and how does it differ from overall survival benefit?
- Are there biomarkers (such as PD-L1, MSI status, or HER2) that should be tested to guide whether immunotherapy is likely to help me?
- What immune-related side effects should I watch for, and how are they managed?
- Are there clinical trials available that combine immunotherapy with other treatments for gastric adenocarcinoma?
This question is drawn from common patient questions about Oncology and answered using cited medical research. We do not provide individualized advice.