[18F-FDG PET/CT in response evaluation of gastrointestinal stromal tumours treated with imatinib]

Rev Esp Med Nucl. May-Jun 2008;27(3):168-75.
[Article in Spanish]


Objective: Several studies have demonstrated the effective use of adjuvant treatment with Imatinib mesylate for unresectable, metastatic or recurrent gastrointestinal stromal tumours (GIST). We retrospectively evaluated the role of 18F-FDG PET/CT scanning in assessing the response of GIST patients to imatinib mesylate therapy.

Materials and methods: Eight consecutive patients with GIST confirmed by surgery (4 stomach, 2 small bowel, 1 small bowel and peritoneum, and 1 rectum) underwent eighteen 18F-FDG PET/CT imaging after beginning imatinib mesylate therapy (400 mg/day or greater if disease progression). PET/CT scan was acquired 60-90 minutes after the intravenous injection of 333-707 MBq of 18F-FDG. Visual and semiquantitative (standardized uptake value [SUV]) analysis of images was performed. Response to therapy was assessed according to EORTC recommendations for PET. Results were confirmed by clinical follow-up, radiographic findings or histological analysis.

Results: Complete response to imatinib mesylate was observed in 5 patients. Four had abdominal lymph nodes, associated with liver metastases in 2, and the other had a residual tumour mass. Partial response (reduction in SUV and in the extent of FDG uptake) was demonstrated in a patient with lung nodules. Disease progression was observed in one patient who had developed new liver metastases on the PET/CT scan. One patient with multiple peritoneal implants and abdominal mass was a non-responder and died 2 months after the 18F-FDG PET/CT.

Conclusion: 18F-FDG PET/CT scan identified the degree of GIST response to imatinib therapy. Patients who responded to therapy showed normalisation of FDG uptake or a decrease in the SUV of lesions.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Agents / therapeutic use
  • Benzamides
  • Drug Monitoring / methods
  • Female
  • Fluorodeoxyglucose F18
  • Gastrointestinal Neoplasms / diagnostic imaging*
  • Gastrointestinal Neoplasms / drug therapy
  • Gastrointestinal Stromal Tumors / diagnostic imaging*
  • Gastrointestinal Stromal Tumors / drug therapy
  • Humans
  • Imatinib Mesylate
  • Liver Neoplasms / diagnostic imaging
  • Liver Neoplasms / drug therapy
  • Liver Neoplasms / secondary
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / secondary
  • Male
  • Middle Aged
  • Piperazines / therapeutic use
  • Positron-Emission Tomography*
  • Pyrimidines / therapeutic use
  • Radiopharmaceuticals
  • Remission Induction
  • Tomography, X-Ray Computed*


  • Antineoplastic Agents
  • Benzamides
  • Piperazines
  • Pyrimidines
  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18
  • Imatinib Mesylate