Treatment of metastatic, imatinib refractory, gastrointestinal stroma tumor with image-guided high-dose-rate interstitial brachytherapy

Brachytherapy. 2019 Jan-Feb;18(1):63-70. doi: 10.1016/j.brachy.2018.09.006. Epub 2018 Oct 29.


Purpose: Evaluation of efficacy and safety of CT- or MRI-guided high-dose-rate interstitial brachytherapy (iBT) in the treatment of advanced, imatinib refractory, metastatic gastrointestinal stroma tumors (GISTs) was the objective of this retrospective study.

Methods and materials: A cumulative number of 40 unresectable metastases (30 hepatic, 10 peritoneal) were treated with iBT in 10 selected patients with histologically proven GISTs. Six patients had peritoneal disease, and 5 patients were even progressing under sunitinib (second line)-thus iBT was applied as a salvage maneuver. IBT uses an interstitially introduced 192iridium source in a high-dose-rate irradiation regime to destroy vital cells in a single fraction. Response to treatment was assessed clinically and with acquisition of MRI/CT every 3 months.

Results: Local tumor control was reached in 97.5% of all treated metastases during a median time of 25 months-only one local relapse was observed during followup. The median diameter of the irradiated lesions was 2.4 cm (range 0.6-11.2 cm); a median dose of 15 Gy (range 6.7-21.96 Gy) was applied. The median progression-free survival after iBT was 6.8 (range 3.0-20.2) months; the median overall survival was 37.3 months (range 11.4-89.7). Two major complications (Common Terminology for Adverse Events grade 3) occurred following the intervention: local hemorrhage and pneumothorax, successfully dealt with by angiographic embolization and pleural drainage, respectively.

Conclusions: In selected patients with metastatic, imatinib refractory GISTs, iBT safely enables high rates of local tumor control and presents an alternative, anti-neoplastic treatment option even in a salvage situation.

Keywords: GIST; Interstitial brachytherapy; Local ablation; Local tumor control; Salvage; TKI resistance.

MeSH terms

  • Adult
  • Aged
  • Antineoplastic Agents / therapeutic use
  • Brachytherapy / adverse effects
  • Brachytherapy / methods*
  • Female
  • Gastrointestinal Stromal Tumors / pathology
  • Gastrointestinal Stromal Tumors / radiotherapy*
  • Hemorrhage / etiology
  • Humans
  • Imatinib Mesylate / therapeutic use
  • Liver Neoplasms / secondary
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local
  • Peritoneal Neoplasms / secondary
  • Pneumothorax / etiology
  • Progression-Free Survival
  • Radiation Injuries / etiology
  • Radiotherapy Dosage
  • Radiotherapy, Image-Guided* / adverse effects
  • Retrospective Studies
  • Salvage Therapy / methods
  • Survival Analysis
  • Tomography, X-Ray Computed


  • Antineoplastic Agents
  • Imatinib Mesylate