First-Line Treatment of Advanced or Metastatic HER2-Negative Gastric Cancer with MSI-H / dMMR

Clinical scenario

This protocol is for patients with advanced or metastatic gastric cancer that is HER2-negative and whose tumour shows microsatellite instability-high (MSI-H) or mismatch repair deficiency (dMMR) — a molecularly defined subpopulation requiring specific first-line management.

Advanced / metastatic HER2-negative MSI-H / dMMR First line

Treatment approach (partial)

First-line treatment for this population is built around a platinum-based chemotherapy combined with a fluoropyrimidine. The selection between available platinum and fluoropyrimidine options takes patient-specific factors — including age and tolerability — into account.

The complete regimen, preferred agent choices, and full dosing algorithm are in the protocol below.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1016/j.annonc.2022.07.004

First-line ChT with a platinum and fluoropyrimidine is recommended. Oxaliplatin is preferred, especially for older patients [I, A].

Recommended platinum compounds are oxaliplatin or cisplatin.

Recommended fluoropyrimidines are intravenous 5-FU, oral capecitabine or oral S-1.

Pembrolizumab is recommended for second-line treatment of patients with MSI-H/dMMR gastric cancer [II, A; ESMO-MCBS v1.1 score: 3; ESCAT score: I-B].

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