Assessing the utility of FDG PET-CT after stereotactic body radiotherapy for early stage non-small cell lung cancer
Menée sur 88 patients atteints d'un cancer du poumon non à petites cellules, cette étude évalue la sensibilité et la spécificité d'une tomographie numérique par émission de positrons à base de fluorodésoxyglucose (18F) pour détecter, trois mois après une radiothérapie corporelle stéréotaxique, une récidive ou un échec thérapeutique
Background : Although SBRT is an established treatment option for early stage lung cancer, there are no guidelines for re-assessing patients after treatment for local treatment failure or intra-thoracic recurrence. This study reports sensitivity, specificity, positive and negative predictive value for FDG PET-CT when utilized to evaluate patients after SBRT.
Methods : Charts were reviewed from all patients who received SBRT and a subsequent FDG PET-CT at a university hospital over a 5 year period. Pre-treatment and 3 month post-treatment tumor characteristics on PET-CT and outcome data (adverse events from SBRT, need for repeat biopsy, rate of local treatment failure and recurrent disease, and all-cause mortality) were recorded.
Results : Eighty-eight patients were included in the study. Fourteen percent (12/88) of patients had a positive 3-month PET. Of the positives, 67% (8/12) were true positives. Eighty-six percent (76/88 patients) had negative 3-month FDG PET-CT’s, with 89% (68/76) true negatives. FDG PET-CT scan performed 3 months following SBRT for NSCLC had a sensitivity of 50% (95% CI: 0.26 – 0.75), specificity of 94% (95% CI: 0.89 – 1.0), positive predictive value of 67% (95% CI: 0.4 – 0.93), and negative predictive value of 89% (95% CI: 0.83 – 0.96).
Conclusions : FDG PET-CT 3 months following treatment of NSCLC with SBRT was a specific but insensitive test for detection of recurrence or treatment failure. Serial CT scans should be used for early surveillance following SBRT while reserving FDG PET-CT to define suspected metastatic disease, evaluate new abnormalities on CT scan, or possibly to reassess later in the follow up period after radiation related inflammation subsides.
CHEST Journal , résumé, 2013