Treatment with adjuvant imatinib for 3 years, which is the current standard of care for patients with high-risk gastrointestinal stromal tumors (GISTs), is generally well-tolerated and effective, according to a new study published in the International Journal of Cancer. This finding is consistent with the clinical outcomes of previous reports.
Factors associated with poor recurrence-free survival include tumor rupture, tumor size of more than 10 cm in diameter, and a high mitotic count (more than 10/50 high power fields), according to the report.
“Based on these risk factors, different management strategies, such as different durations of adjuvant imatinib, deserve further investigation,” the authors wrote. The aim of the study was to investigate the safety and efficacy of this treatment approach and the prognostic value of different factors.
Read more about the prognosis of GIST
The researchers analyzed a total of 222 patients with high-risk GISTs who had surgery plus adjuvant therapy with imatinib for 3 years. The dose of imatinib was reduced in 39 patients (17.6% of all patients) and discontinued in 13 patients (5.9% of all patients) due to toxicity.
The 5-year recurrence-free survival rate was 73.2% and the overall survival rate was 93.9%. When they stratified patients according to risk factors, the researchers found that those without tumor rupture, a tumor bigger than 10 cm, or a high mitotic count, had a 5-recurrence-free survival rate of 83.8%.
Patients with only a tumor bigger than 10 cm had a 5-year recurrence-free survival rate of 92.3%. On the contrary, the 5-year recurrence-free survival rate of those with a tumor rupture was 54.8% and that of patients with a tumor bigger than 10 cm and a mitotic index of more than 10/50 high power fields was 47.9%.
The researchers concluded that 3 years of treatment with imatinib following surgery was tolerable and effective for high-risk GISTs.
Bang YH, Ryu MH, Kim HD, Lee HE, Kang YK. Clinical outcomes and progleevegnostic factors for patients with high-risk gastrointestinal stromal tumors treated with 3-year adjuvant imatinib. Int J Cancer. Published online June 9, 2022. doi:10.1002/ijc.34157