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KIT Mutation Testing Yields Survival Benefit for GIST Patients
A long-term analysis of patients with localized and metastatic GIST determined there were survival differences associated with KIT mutation testing and other clinical variables (Am J Clin Oncol. 2020 Apr 4. Epub ahead of print).
“The objective of this study was to determine whether there were survival differences associated with KIT mutation testing, type of KIT mutations, and other clinical variables in patients with localized or metastatic [GIST],” wrote Jorge Florindez, MD, Divisions of Hospital Medicine, and colleagues.
The primary end points were overall survival (OS) and cancer-specific survival (CSS).
Data for a total of 3866 patients with GIST from 2010 to 2015 were extracted from the SEER database and included in the study.
Of these patients, 656 had metastatic disease and 3210 had localized disease. The researchers found that KIT mutation testing was performed in 26.7% of patients (n = 1033).
Multivariate analysis in localized disease showed worse OS for Black patients (hazard ratio [HR], 1.57); higher mitotic rate demonstrated poor OS (HR, 1.59) and CSS (HR, 3.07); and tumor size was tied to poor CSS (HR, 5.73).
In addition, multivariate analysis in metastatic GIST showed poor OS (HR, 1.42) and CSS (HR, 1.73) for Black patients; KIT testing was associated with better OS (HR, 0.64) and CSS (HR, 0.66); and treatment with tyrosine kinase inhibitors was associated with better OS (HR, 0.67).
In localized and metastatic GIST, surgical resection was associated with better OS (HR, 0.56) and CSS (HR, 0.55).
Dr Florindez et al determined there were survival differences associated with KIT mutation testing and other clinical variables in patients with GIST.
Although the minority of GIST patients are tested for KIT mutations, KIT testing and tyrosine kinase inhibitor therapy are associated with better survival in those with metastatic disease.—Kaitlyn Manasterski
