Treatment of Advanced or Metastatic Gastric Cancer with HER2 Overexpression

In advanced or metastatic gastric cancer, HER2 status is a key biomarker that shapes first-line treatment decisions. Patients whose tumours show HER2 overexpression represent a distinct sub-population for which a specific, evidence-based first-line approach is recommended.

Clinical Scenario

Advanced or metastatic gastric cancer with HER2 overexpression, defined as HER2 IHC 3+, or HER2 IHC 2+ confirmed FISH positive. This biomarker profile identifies patients who are candidates for a targeted first-line strategy.

First-Line Approach (Overview)

For this HER2-positive population, first-line management involves adding a targeted agent to a platinum-fluoropyrimidine chemotherapy backbone. The complete regimen — including the choice of platinum, fluoropyrimidine formulation, and full treatment algorithm — is detailed in the structured protocol.

Full regimen, dosing, and sequencing available in the structured protocol below.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1016/j.annonc.2022.07.004

Adding trastuzumab to ChT is recommended for patients with HER2-overexpressing (HER2 IHC 3+ or IHC 2+/FISH positive) gastric cancer, based on the phase III ToGA study, which demonstrated higher response rates and longer OS with trastuzumab+ChT compared with ChT alone; additional toxicity was low and manageable.
Trastuzumab+ChT is recommended in patients with HER2-positive tumours [I, A; ESMO-MCBS v1.1 score: 3; ESCAT score: I-A].

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