Treatment of pMMR/MSS Metastatic Colon Cancer with HER2 Overexpression and Wild-Type KRAS, NRAS, and BRAF

This protocol applies to patients with metastatic colon adenocarcinoma whose tumour is proficient mismatch repair (pMMR) and microsatellite stable (MSS), shows HER2 (ERBB2) overexpression or amplification, and carries no mutations in KRAS, NRAS, or BRAF.

Clinical Scenario

This population is defined by a specific combination of molecular features:

Proficient mismatch repair (pMMR) and microsatellite stable (MSS)
HER2 (ERBB2) overexpression or amplification
KRAS wild-type, NRAS wild-type, BRAF wild-type
Metastatic colon adenocarcinoma

Treatment Approach

For this molecularly defined population, management centres on HER2-directed targeted therapy. The protocol provides specific anti-HER2 combination regimens, with options that vary according to the level of HER2 expression.

Full regimen details, selection criteria, and sequencing are available in the complete structured protocol.

Instant Access to Structured Evidence-Based Regimens

References

pMMR/MSS
(Pertuzumab or Tucatinib) + Trastuzumab (HER2 (ERBB2) overexpression/amplification)
HER2 overexpression (IHC 3+)
Fam-trastuzumab deruxtecan-nxki (HER2 overexpression [IHC 3+])

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