Apport diagnostique des acquisitions dynamiques précoces dans la caractérisation des foyers prostatiques en TEP/TDM à la 18-Fluorocholine dans les récidives de cancer de la prostate

Abstract

ObjectiveThe aim of this study was to determine if early kinetic uptake data of 18-Fluorocholine (FCH) PET/CT can help distinguish malignant prostatic lesions from benign tissue in patients with biochemical recurrence of prostate cancer. MethodsThis is a retrospective study of 28 patients with biochemical recurrence of prostate cancer, who underwent FCH PET/CT and prostate biopsies with anatomopathological examination, at the university hospital of Poitiers between June 2012 and June 2014. Each exam began immediately after the injection of FCH, with a 10minutes dynamic acquisition over the pelvic region and a late whole body acquisition 10minutes later. The SUVmax evolution for histologically proven malignant and benign prostatic lesions was compared using the ROC curves methodology. ResultsMedian PSA was 5.22ng/mL. Forty-eight lesions were investigated, of which 24 were malignant. Visual analysis of late images showed a sensitivity, specificity and accuracy of 95.8% 87.5% and 91.7% respectively. Considering the entire acquisition, SUVmax was significantly higher for malignant than benign lesions (P<0.0001), with comparable performances at all time points after the first 3minutes. Initial FCH accumulation (faster for malignant lesions) allowed for a good lesion discrimination (P=0.0015). However, this criterion did not allow improving diagnostic performance. Then, FCH uptake was slowly decreasing until the 20th minute for all lesions, albeit more significantly for benign lesions. ConclusionA quantitative analysis of FCH uptake kinetics did not improve diagnostic performances and in contrast to what has been previously suggested, decreasing FCH uptake over time did not exclude malignancy.