Gastrointestinal stromal tumor
ICD-10 C49.4 · ICD-11 2B5B

Treatment of Metastatic Gastrointestinal Stromal Tumor with KIT or PDGFRA Mutation

Clinical Scenario

This protocol is for patients with metastatic gastrointestinal stromal tumor (GIST) whose tumor harbors a KIT or PDGFRA mutation, but specifically without a KIT exon 9 mutation and without a PDGFRA D842V mutation. Establishing genotype is mandatory before initiating treatment in advanced or metastatic disease.

KIT mutation ✓ PDGFRA mutation ✓ KIT exon 9 — absent PDGFRA D842V — absent

Treatment Approach

First-line targeted therapy is the foundation of management for this mutation profile. When disease control becomes insufficient, dose escalation of the initial agent may be considered before moving to established second-line targeted options. The decision between strategies depends on mutation characteristics and individual clinical factors.

The complete protocol — including agent selection, sequencing criteria, and dosing schedules — is available in the full evidence-based regimen.

Instant Access to Structured Evidence-Based Regimens
References

DOI: 10.1177/17588359231192388

Genotype is mandatory for treating advanced/metastatic GIST patients (II,A).

Imatinib 400 mg daily is the recommended dose in the first line (I,A).

One option to consider is to increase the dose to 400 mg twice daily.

Before sunitinib, imatinib dose escalation to 400 mg twice daily can be considered, particularly in patients with KIT exon 9-mutant GIST (III,B).

After the failure of imatinib, the standard second-line treatment is sunitinib 50 mg daily 4/2 (I,A) or 37.5 mg continuously (III,C).

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