11c-choline-PET/CT versus transrectal ultrasound-guided prostate biopsy to diagnose locally recurrent prostate cancer following radiation therapy.

Abstract

119 Background: Radical salvage prostatectomy (SRP) represents one local secondary treatment option with curative intent in patients failing radiation therapy (RT) for localized prostate cancer (PCA). 11C-PET/CT represents an innovative imaging study to detect systemic spread of prostate cancer. However, there is only limited experience with regard to the sensitivity of C-PET/CT to detect locally recurrent PCA following radiation therapy. The purpose of our study was to analyse the sensitivity of C-PET/CT to diagnose PCA and extra- and intraprostatic extension. Methods: 45 patients with the suspicion of locally recurrent PCA underwent 12-core transrectal ultrasound- guided biopsy of the prostate, C-PET/CT, bonne scan and radical salvage prostatectomy. Findings of the imaging studies were correlated with the pathohistological findings of the prostate biopsy and the radical prostatectomy specimen. All prostatectomy specimens were proceeded according to the Stanford protocol and the number and location of intraprostatic cancer foci > 5mm were correlated with the PE/CT findings. Results: The mean preoperative serum PSA was 7.8 (2–24) ng/ml; the mean biopsy Gleason Score was 5.6 (4–9). Prostate biopsy was positive in 37/45 (82.2%) patients whereas 8/45 (17.8%) had a negative biopsy despite positive PET/CT findings. PET/CT was positive in 45/45 patients. Radical prostatectomy specimens identified locally recurrent PCA in 44/45 (97.8%). One patient turned out to have pT0pN0 disease despite increasing PSA. PET/CT identified 1, 2, and > 2 intraprostatic cancer foci of significant volume in 23 (51.1%), 13 (28.9%) and 9 (20%) patients, respectively. Sensitivity to detect intraprostatic, histologically proven PCA foci is 95.6% which is significantly superior to the biopsy results. There was a high correlation between the PET/CT results and the final histology of the radical prostatectomy specimens. Conclusions: Choline PET/CT is an innovative imaging to identify patients with locally recurrent PCA following radiation therapy. PET/CT is superior to prostate biopsy and we recommend a PET/CT in patients who are candidates for radical salvage prostatectomy. No significant financial relationships to disclose.