Discontinuation of imatinib in patients with oligometastatic gastrointestinal stromal tumour who are in complete radiological remission: a prospective multicentre phase II study

Acta Oncol. 2024 May 7:63:288-293. doi: 10.2340/1651-226X.2024.39851.


Introduction: Metastatic gastrointestinal stromal tumour (GIST) is considered incurable, and life-long treatment with tyrosine kinase inhibitors is recommended. We investigated whether selected patients with metastatic GIST may remain in durable remission despite imatinib discontinuation.

Patients: In this 1-group, prospective, multicentre phase II trial selected patients with oligometastatic (≤3 metastases) GIST discontinued imatinib treatment. Eligible patients had been treated with imatinib >5 years without progression and had no radiologically detectable metastases after metastasectomy, radiofrequency ablation (RFA) or complete response to imatinib. The primary endpoint was progression-free survival (PFS) 3-years after stopping imatinib. Overall survival (OS) and quality of life (QoL) were secondary endpoints.

Results: The trial closed prematurely due to slow accrual. Between January 5, 2017, and June 5, 2019, 13 patients were enrolled, of whom 12 discontinued imatinib. The median follow-up time was 55 months (range, 36 to 69) after study entry. Five (42%) of the 12 eligible patients remained progression free, and seven (58%) progressed with a median time to progression 10 months. Median PFS was 23 months and the estimated 3-year PFS 41%. Six of the seven patients who progressed restarted imatinib, and all six responded. Three-year OS was 100%, and all patients were alive at the time of the study analysis. QoL measured 5 and 11 months after discontinuation of imatinib demonstrated improvement compared to the baseline.

Interpretation: A substantial proportion of selected patients with oligometastatic GIST treated with imatinib and metastasis surgery/RFA may remain disease-free for ≥3 years with improved QoL after stopping of imatinib.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Agents* / therapeutic use
  • Female
  • Gastrointestinal Neoplasms / drug therapy
  • Gastrointestinal Neoplasms / mortality
  • Gastrointestinal Neoplasms / pathology
  • Gastrointestinal Neoplasms / therapy
  • Gastrointestinal Stromal Tumors* / drug therapy
  • Gastrointestinal Stromal Tumors* / mortality
  • Gastrointestinal Stromal Tumors* / pathology
  • Gastrointestinal Stromal Tumors* / surgery
  • Gastrointestinal Stromal Tumors* / therapy
  • Humans
  • Imatinib Mesylate* / therapeutic use
  • Male
  • Middle Aged
  • Neoplasm Metastasis
  • Progression-Free Survival
  • Prospective Studies
  • Protein Kinase Inhibitors / therapeutic use
  • Quality of Life*
  • Remission Induction
  • Withholding Treatment


  • Imatinib Mesylate
  • Antineoplastic Agents
  • Protein Kinase Inhibitors