Early response evaluation using 18F-FDG-PET/CT does not influence management of patients with metastatic gastrointestinal stromal tumors (GIST) treated with palliative intent

Nuklearmedizin - NuclearMedicine, vol. 60, pp. 411–416

Abstract

Abstract Aim The aim of this study was to investigate the impact of 18F-FDG-PET/CT on treatment decision making in metastatic gastrointestinal stromal tumor (GIST) patients. Methods This study retrospectively evaluated 18F-FDG-PET/CT scans to monitor response of metastatic GIST patients treated with palliative intent. Data from the Dutch GIST Registry was used. Early scans (<10 weeks after start of treatment) and late scans (>10 weeks after start of treatment) were scored on the impact in change of treatment. Results Sixty-one PET/CT scans were performed for treatment evaluation in 39 patients with metastatic GIST of which 36 were early scans and 25 were late scans. Early PET/CT scans led to a change in management in 5.6% of patients and late PET/CT scans led to a change in management in 56% of patients. Change in management was more often seen after scans with lack of metabolic response (48% vs. 11% in scans with metabolic response, p=0.002). Neither metabolic response nor change in treatment were more often seen in patients with KIT mutations compared to patients with non-KIT mutations (metabolic response 65% KIT vs. 46% non-KIT, p=0.33, and change in management 28% KIT vs. 21% non-KIT, p=0.74). Conclusion 18F-FDG-PET/CT is not recommended for early response evaluation in an unselected patient population with metastatic GIST, since it does not influence treatment decisions. 18F-FDG-PET/CT, however, can be useful for late response assessment, especially in case of indeterminate CT results.

Authors 10

1. Sheima Farag Aachen Department of Medical Oncology

   Leiden University Medical Center · The Netherlands Cancer Institute

   Affiliation as printed

   Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands

   Department of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands

2. Nikki S. IJzerman

   Erasmus MC · The Netherlands Cancer Institute · Erasmus MC Cancer Institute

   Affiliation as printed

   Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands

   Department of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands

3. Matthijs P.M. Houdijk Aachen Department of Radiology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

4. Anna K.L. Reyners

   University Medical Center Groningen

   Affiliation as printed

   Department of Medical Oncology, University Medical Centre Groningen, Groningen, Netherlands

5. Anne I.J. Arens

   Radboud University Medical Center

   Affiliation as printed

   Department of Radiology, Nuclear Medicine and Anatomy, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

6. Dirk Jan Grünhagen

   Erasmus MC · Erasmus MC Cancer Institute

   Affiliation as printed

   Department of Surgical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands

7. Ingrid M.E. Desar

   Radboud University Medical Center

   Affiliation as printed

   Department of Medical Oncology, Radboud University Medical Center, Nijmegen, Netherlands

8. Hans A. J. Gelderblom Aachen Department of Medical Oncology

   Leiden University Medical Center

   Affiliation as printed

   Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands

9. Neeltje Steeghs

   The Netherlands Cancer Institute

   Affiliation as printed

   Department of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands

10. Lioe‐Fee de Geus‐Oei Aachen Department of Radiology, Leiden University Medical Center

    Leiden University Medical Center · University of Twente

    Affiliation as printed

    Department of Biomedical Photonic Imaging Group, University of Twente, Enschede, Netherlands

    Department of Radiology, Leiden University Medical Center, Leiden, Netherlands