Author of

• 17728

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  P2.04 - Poster Session with Presenters Present (ID 466)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Mesothelioma/Thymic Malignancies/Esophageal Cancer/Other Thoracic Malignancies
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 17735

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    P2.04-007 - Role of F-18-Choline Petscan in Recurrence of Thymic Epithelial Tumors (TET) (ID 5971)

    14:30 - 14:30  |  Author(s): C. Le Pechoux
    • Abstract

    Background:
    Fluorine-18-fluorodeoxyglucose (F-18-FDG) uptake in TETs is highly variable based on histology subtype. The fluorine-18-choline (F-18-choline) PET/CT scan represents an emerging important tool in the management of tumors with low glucose metabolism. There have been few case reports describing positive choline uptakes in TETs. The aim of this study is to evaluate the clinical use of choline PET/CT in TET.
    
    Methods:
    We conducted a retrospective analysis of patients (pts) with diagnosis of TETs who underwent an F-18- choline PET/CT exam in the course of their disease from Jan 2012 to May 2016. Pathologic and clinical data were extracted from medical records. FDG exams with a mean standardize uptake value (SUV) higher than 4.5 and choline exams with uptake more than two times the physiologic value, were considered as positive.
    
    Results:
    A total of 10 pts were included for analyses. Among them, 8 pts were males; median age was 43 years [32-62], 8 pts presented an autoimmune disorder (62 % myasthenia gravis); 8 had thymoma (T) and 2 had thymic carcinoma (TC). All patients underwent choline PET/CT in order to evaluate suspected recurrence and/or progression. Positive choline scans were observed in 7 pts with a median SUV of 6.5 [4.8-7.8] with the following histology subtype distribution: B1 / B2 / TC in 2 / 3 / 2 pts respectively. Negative choline scan was observed in 3 pts with AB, B1 and B2 histology subtypes. Five patients (50%) showed disagreement between F-18-FDG and F-18-choline scans results. Among them, 3 pts with a negative FDG scan had a positive choline PET/CT, showing an isolated recurrence amenable to local treatment in two of them; disseminated progression excluded local treatment for the remaining patient. Diagnosis of mediastinal relapse was suspected for 2 pts on positive mediastinal FDG uptake but excluded based on a negative choline scan and MRI findings; both of them had history of mediastinal adjuvant radiotherapy. Agreement was seen between both modalities for 4 pts.
    
    Conclusion:
    Discordance between FDG and choline scans was observed for half of the pts. When FDG scan was negative, the addition of choline PET/CT impacted disease management in 75% of the cases. History of adjuvant mediastinal radiotherapy could constitute a frequent cause of false positive FDG scan with negative choline findings; therefore, choline scan might also represent a useful exam to exclude mediastinal relapses in this scenario.