A growing number of patients with metastatic gastrointestinal stromal tumor (mGIST) may be able to achieve 10-year survivorship thanks to multiple tyrosine kinase inhibitor (TKI) therapies available, according to a study published in Annals of Surgical Oncology.

“Patients with metastatic GIST have experienced dramatically improved outcomes in the modern era of the multiple TKI therapies available, with 10-year survivorship likely achievable in at least 40% of patients compared with 25% 5-year survival in the pre-imatinib era,” the study’s authors said.

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Out of 109 patients diagnosed with mGIST, 46 (42%) achieved 10-year survival. The time to first progression seemed to be an important factor for 10-year survivorship. Of patients who had primary progression in the first 2 years after diagnosis, only 14% achieved 10-year survival. Only 35% who experienced progression between 2 and 5 years post-diagnosis achieved 10-year survival, and 88% of those having progression after 5 to 10 years achieved 10-year survival.

“The principal driver of prognosis in this population is time to first progression on first-line therapy; however, disease progression is an apparently stochastic event, with progression at times separated by 5 years or more in patients with identical driver mutations,” the authors continued.

Univariable analysis of patients who did not reach 10-year survival found that age at diagnosis, therapeutic-intent metastasectomy, and years to first progression were all factors. Multivariable analysis found that longer time to progression was independently associated with increased odds of achieving 10-year survival, while more advanced age at diagnosis was independently associated with decreased odds.

The 109 patients recruited for the 16-year study had experienced mortality or had 10 years or greater of follow-up. The median age of patients was 57 at diagnosis, however the median age of 10-year survivors was lower, at 49.5, compared to 62.5 in nonsurvivors (P <.001). Mutational status was not significantly different between survivors and nonsurvivors (P =.08) but only 1 of the 8 patients with PDGFRA mutations achieved survival.

All patients in the study with KIT and non-D842V PDGFRA mutations were started on first-line imatinib. Some patients with D842V PDGFRA were started on imatinib before it was known to be resistant to treatment.

Reference

Sutton TL, Walker BS, Billingsley KG, et al. Ten-year survivorship in patients with metastatic gastrointestinal stromal tumors. Ann Surg Oncol. Published online July 12, 2022. doi:10.1245/s10434-022-12063-5