Sheima Farag1, Lioe-Fee de Geus-Oei2,3, Winette T van der Graaf4,5, Frits van Coevorden6, Dirk Grunhagen7, Anna K L Reyners8, Pieter A Boonstra8, Ingrid Desar4, Hans Gelderblom9, Neeltje Steeghs10. 1. Department of Medical Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands. 2. Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. 3. MIRA Institute, University of Twente, Enschede, The Netherlands. 4. Department of Medical Oncology, Radboud University Medical Center, Nijmegen, The Netherlands. 5. Institute of Cancer Research, London, United Kingdom. 6. Department of Surgical Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands. 7. Department of Surgical Oncology, Erasmus MC-Cancer Institute, Rotterdam, The Netherlands. 8. Department of Medical Oncology, University Medical Center Groningen, Groningen, The Netherlands; and. 9. Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands. 10. Department of Medical Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands n.steeghs@nki.nl.
Abstract
18F-FDG PET has previously been proven effective as an early way to evaluate the response of gastrointestinal stromal tumors (GISTs) to imatinib treatment. However, it is unclear whether early evaluation of response affects treatment decisions in GIST patients treated with neoadjuvant intent. Methods: We retrospectively scored changes in management based on early evaluation of response by 18F-FDG PET in patients in the Dutch GIST registry treated with neoadjuvant imatinib. Results: Seventy 18F-FDG PET scans were obtained for 63 GIST patients to evaluate for an early response to neoadjuvant imatinib. The scans led to a change in management in 27.1% of the patients. Change in management correlated strongly with lack of metabolic response (P < 0.001) and non-KIT exon 11-mutated GISTs (P < 0.001). Conclusion: Performing 18F-FDG PET for early evaluation of response often results in a change of management in GIST patients harboring the non-KIT exon 11 mutation and should be considered the standard of care in GIST patients treated with neoadjuvant intent.
18F-FDG PET has previously been proven effective as an early way to evaluate the response of gastrointestinal stromal tumors (GISTs) to imatinib treatment. However, it is unclear whether early evaluation of response affects treatment decisions in GISTpatients treated with neoadjuvant intent. Methods: We retrospectively scored changes in management based on early evaluation of response by 18F-FDG PET in patients in the Dutch GIST registry treated with neoadjuvant imatinib. Results: Seventy 18F-FDG PET scans were obtained for 63 GISTpatients to evaluate for an early response to neoadjuvant imatinib. The scans led to a change in management in 27.1% of the patients. Change in management correlated strongly with lack of metabolic response (P < 0.001) and non-KIT exon 11-mutated GISTs (P < 0.001). Conclusion: Performing 18F-FDG PET for early evaluation of response often results in a change of management in GISTpatients harboring the non-KIT exon 11 mutation and should be considered the standard of care in GISTpatients treated with neoadjuvant intent.