68Ga-PSMA 11 ligand PET imaging in patients with biochemical recurrence after radical prostatectomy - diagnostic performance and impact on therapeutic decision-making.

OBJECTIVE: To evaluate the diagnostic performance of [68Ga]Ga-PSMAHBED-CC conjugate 11 positron emission tomography (PSMA-PET) in the early detection of metastases in patients with biochemical recurrence (BCR) after radical prostatectomy (RP) for clinically non-metastatic prostate cancer, to compare it to CT/MRI alone and to assess its impact on further therapeutic decisions. MATERIAL AND METHODS: We retrospectively assessed 117 consecutive hormone-naïve BCR patients who had 68Ga-PSMA 11 PET/CT (n = 46) or PET/MRI (n = 71) between May 2014 and January 2017. BCR was defined as two PSA rises above 0.2 ng/ml. Two dedicated uro-oncological imaging experts (radiology/nuclear medicine) reviewed separately all images. All results were presented in a blinded sequential fashion to a multidisciplinary tumorboard in order to assess the influence of PSMA-PET imaging on decision-making. RESULTS: The median time from RP to BCR was 36 months (IQR 16-72). Overall, 69 (59%) patients received postoperative radiotherapy. Median PSA level at the time of imaging was 1.04 ng/ml (IQR 0.58-1.87). PSMA-positive lesions were detected in 100 (85.5%) patients. Detection rates were 65% for a PSA value of 0.2 to <0.5 ng/ml, 85.7% for 0.5 to <1, 85.7% for 1 to <2 and 100% for ≥2. PSMA-positive lesions could be confirmed by either histology (16%), PSA decrease in metastasis-directed radiotherapy (45%) or additional information in diffusion-weighted imaging when PET/MRI was performed (18%) in 79% of patients. PSMA-PET detected lesions in 67 patients (57.3%) who had no suspicious correlates according to the RECIST 1.1 criteria on MRI or CT. PSMA-PET changed therapeutic decisions in 74.6% of these 67 patients (p < 0.001), with 86% of them being considered for metastases-directed therapies. CONCLUSIONS: We confirm the high performance of PSMA-PET imaging for the detection of disease recurrence sites in patients with BCR after RP, even at relatively low PSA levels. Moreover, it adds significant information to standard CT/MRI, changing treatment strategies in a significant number of patients.

Distribution of prostate carcinoma foci within the peripheral zone: analysis of 8,062 prostate biopsy cores.

The aim of this study was to evaluate the distribution of prostate cancer within the peripheral zone by prostate biopsies excluding the influence of the transition zone. A prospective, multicenter study was carried out using a consecutive series of men who underwent transrectal ultrasound guided prostate biopsies using different biopsy techniques at six institutions. Biopsies were directed strictly within the peripheral zone or strictly within the transition zone. A model of the peripheral zone with 18 sectors of similar volume was established and the biopsy cores obtained were associated with these sectors and analysed with respect to prostate cancer detection rate. A total of 904 men (mean age 66.8 years, range 42-86) with a median serum PSA of 8.1 ng/ml (2.2-940 ng/ml) entered the study. A total of 8,062 biopsy cores (mean 8.92/patient) were obtained. Each of the peripheral zone sectors tested by biopsies yielded a similar percentage of prostate cancer ( P=0.6). There was no increase in the incidence of cancer toward the lateral sectors compared to midline sectors ( P=0.53) of the peripheral zone. Biopsy sampling of the peripheral zone from the apex to the base yielded a similar percentage of prostate cancer ( P=0.47). Our data suggest that the distribution of cancer foci detected by biopsies in the peripheral zone of the prostate is homogeneous.