The specific type of mutation, the location of the tumor, and the Ki-67 index value may affect the prognosis of patients with gastrointestinal stromal tumor (GISTs) with platelet-derived growth factor receptor alpha (PDGFRA) mutations, according to a retrospective study published in Advances in Therapy.
The results showed that D842-V mutations (P =.017), nongastric tumor locations (P <.001), and Ki-67 labeling index >5% (P =.005) were all independent factors reducing the relapse-free survival (RFS) of patients with GISTs following complete resection surgery.
“Mutation type, tumor site, and Ki-67 index are independent prognostic factors for patients with PDGFRA-mutant GIST. The prediction model based on the three aforementioned variables showed good predictive effects for these patients and which might provide insights for clinical strategies and treatments,” the authors summarized.
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A total of 280 patients with GISTs with PDGFRA mutations were enrolled in the retrospective study who underwent resection surgery between January 1, 2005, and December 31, 2019. Tumor recurrence was observed in 26 patients (8.7%) and yielded 1-, 3-, and 5-year RFS rates of 95.9%, 91.2%, and 89.5%, respectively.
Of the 280 patients, 172 (61.4%) had D842V mutations in exon 18 of the PDGFRA gene, while the remaining 108 had other, non-D842V mutations of the same gene. The patients without the D842V mutation had a better prognosis than those with the specific mutation (P =.033). The 1-, 3-, and 5-year RFS for patients with the D842V mutation were 94.6%, 88.3%, and 86.6%, respectively, compared to 98.1%, 95.8%, and 94.3% for those without the mutation.
The majority of tumors resected during the study were located in the stomach (89.6%). Multivariate Cox regression found that patients with nongastric tumor sites were almost 5 times more likely to relapse (hazard ratio [HR], 4.819; 95% CI, 2.123-10.939; P <.001) than patients with gastric tumors. Regression analysis also found that Ki-67 index values above 5% were also at a higher risk of relapse (HR, 3.115; 95% CI, 1.407–6.894; P =.005).
Zhang P, Wang M, Li J, et al. Clinicopathologic characteristics and prognosis of PDGFRA-mutant gastrointestinal stromal tumors: a large-scale, multi-institutional, observational study in China. Adv Ther. Published online April 24, 2022. doi:10.1007/s12325-022-02115-3