18F-Choline PET/CT and multiparametric MRI for the detection of early local recurrence of prostate cancer initially treated by radiotherapy: comparison with systematic 3D-transperineal mapping biopsy

Publication date: Available online 28 December 2016
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Salim Kanoun, Paul Walker, Jean-Marc Vrigneaud, Edouard Depardon, Vincent Barbier, Olivier Humbert, Morgan Moulin, Gilles Créhange, Luc Cormier, Romaric Loffroy, François Brunotte, Alexandre Cochet
PurposeTo compare the diagnostic performance of ¹⁸F-Fluorocholine PET/CT (FCH-PET/CT), multiparametric prostate MRI (mpMRI) and a combination of both techniques for the detection of local recurrence of prostate cancer initially treated by radiotherapy.MethodsThis was a retrospective single-institution study of 32 patients with suspected prostate cancer recurrence, who underwent both FCH-PET/CT and 3T mpMRI within 3 months of one another for the detection of recurrence. All included patients had to be cleared for metastatic recurrence. The reference procedure was systematic 3D-transperineal prostate biopsy for the final assessment of local recurrence. Both imaging modalities were analyzed by two experienced readers blinded to clinical data. The analysis was made per-patient and per-segment using a 4-segment model.ResultsThe median PSA at the time of imaging was 2.92ng/mL. The mean PSA doubling time was 14 months. Of the 32 patients, 31 had a positive 3D-transperineal mapping biopsy for a local relapse. On a patient-based analysis, the detection rate was 71% (22/31) for mpMRI and 74% (23/31) for FCH-PET/CT. On a segment-based analysis, the sensitivity and specificity were 32% and 87% for mpMRI, 34% and 87% for FCH-PET/CT, and 43% and 83% for the combined analysis of both techniques. Accuracy was 64, 65 and 66% respectively. The inter-observer agreement was kappa=0.92 for FCH-PET/CT and kappa=0.74 for mpMRI.ConclusionsBoth mpMRI and FCH-PET/CT show limited sensitivity but good specificity for the detection of local cancer recurrence after radiotherapy, when compared with 3D-transperineal mapping biopsy. Prostate biopsy still appears mandatory to diagnose local relapse and select patients who could benefit from local salvage therapy.

Teaser

The aim of the study is to compare the diagnosis performances of 18FCH-PET/CT and mpMRI in the diagnosis of early local relapse of prostate cancer. We designed a retrospective study with a systematic gold standard 3D-mapping biopsy. The results highlight the low sensitivity of both imaging modalities and the importance of prostate biopsies to assess intra-prostatic relapse before local salvage treatment.


http://ift.tt/2hwQgyT