Findings in 1,123 Men with Preoperative 68Ga-Prostate-Specific Membrane Antigen Positron Emission Tomography/Computerized Tomography and Multiparametric Magnetic Resonance Imaging Compared to Totally Embedded Radical Prostatectomy Histopathology: Implications for the Diagnosis and Management of Prostate Cancer.

PURPOSE: Multiparametric magnetic resonance imaging (mpMRI) fails to identify some men with significant prostate cancer. Prostate-specific membrane antigen positron emission tomography/computerized tomography (PSMA PET/CT) is recommended for staging of prostate cancer, but its additional benefit above mpMRI alone in local evaluation for prostate cancer is unclear. The study aim was to evaluate the ability of mpMRI and PSMA PET/CT individually and in combination, to predict tumor location and Gleason score ≥3+4 on robot-assisted laparoscopic radical prostatectomy (RALP) histology. MATERIALS AND METHODS: We retrospectively reviewed 1,123 men with a preoperative mpMRI and 68Ga-PSMA PET/CT prior to a RALP. Tumor locations were collected from both imaging modalities and compared to totally embedded prostate histology. Lowest apparent diffusion coefficient value on mpMRI and the highest maximum standardized uptake value (SUVmax) on 68Ga-PSMA PET/CT were collected on the index lesions to perform analysis on detection rates. RESULTS: Median prostate specific antigen was 6. Median Gleason score on biopsy and RALP histology was 4+3. The index lesion and multifocal tumor detection were similar between mpMRI and 68Ga-PSMA PET/CT (p=0.10; p=0.11). When combining mpMRI and 68Ga-PSMA PET/CT, index Gleason score ≥3+4 cancer at RALP was identified in 92%. Only 10% of patients with Gleason score ≤3+4 on biopsy with an SUVmax <5 were upgraded to ≥4+3 on RALP histology, compared to 90% if the SUVmax was >11. CONCLUSIONS: The addition of a diagnostic 68Ga-PSMA PET/CT to mpMRI can improve the detection of significant prostate cancer and improve the ability to identify men suitable for active surveillance.

Reconsidering the role of pelvic lymph node dissection with radical prostatectomy for prostate cancer in an era of improving radiological staging techniques.

BACKGROUND: Performing an extended pelvic lymph node dissection (PLND) on all men with intermediate- and high-risk prostate cancer at the time of a radical prostatectomy (RP) remains controversial. The majority of patients PLND histology is benign, and the long-term cancer-free progression in men with positive lymph node metastasis is low. The objective is to investigate the probability of long-term biochemical freedom from recurrent disease (bNED) in men with lymph node metastasis identified at the time of radical prostatectomy (RP). SUBJECTS AND METHODS: A retrospective review of the pathology of 1184 pelvic lymph node dissections performed at the time of a radical prostatectomy by multiple surgeons referred to a single uro-pathology laboratory between 2008 and 2014 identified 61 men with node-positive prostate cancer. Of the men with positive nodes, 24 had a standard PLND and 37 an extended PLND (ePLND). bNED was defined as a post-operative serum PSA < 0.2 ng/ml. RESULTS: The median follow-up is 4 years (2-8). The median lymph node count was 7 (range 2-16) for PLND and 22 (range 6-46) for the ePLND. A single lymph node metastasis was identified in 56% of the 61 men. Only 10% of men with a positive lymph node metastasis remained free of biochemical recurrence of disease, and only 5% had undetectable serum PSA. There was no difference in bNED outcome between a PLND and ePLND. The number of men needed to be treated with a PLND at the time of RP (NNT) to result in an undetectable post-operative PSA at a median follow-up of 4 years is 395. CONCLUSIONS: In men with lymph node metastasis, the probability of long-term bNED is low and the NNT for cure is high. With emerging improved radiological imaging techniques increasing the detection of lymph node metastasis outside the extended lymph node dissection templates, more scientific investigation is required to evaluate which men will benefit from a PLND and which men can avoid an unnecessary PLND procedure.