Faculty Bibliography

OBJECTIVE: To provide insights into the role of mpMRI for predicting oncological control following two focal ablation (FA) templates for selective cases of prostate cancer (PCa). MATERIALS AND METHODS: 59 radical prostatectomies were performed between 2012 and 2016 on cases that fulfilled criteria for FA. The Gleason score (GS), extent of Gleason pattern (GP) 4, maximum linear cross sectional length (MLCSL) and location of tumor foci were recorded and related to scale on corresponding 3mm transverse slice prostate maps. Gleason pattern 4 extra-focal disease (GP4EFD) was defined as PCa with any GP 4 not detected by mpMRI and transrectal ultrasound systematic biopsy observed outside a specified ablation zone. The location of these GP4EFD relative to the MRI lesion (MRI-L) (contralateral or ipsilateral) was recorded and used to predict oncological control following a hypothetical margin and ipsilateral hemi-ablation templates. RESULTS: Overall, 15/59 (25.4%) of the prostate specimens had at least one GP4EFD. Of the total 20 GP4EFD, 7/20 (35%) were ipsilateral and 13/20 (65%) were contralateral to the MRI-L. Of the GP4EFD, 16/20 (80%), 2/20 (10%), and 2/20 (10%) were GS 3+4, GS 4+3, and GS 4+4, respectively. Of these GP4EFD, 10/20 (50%) exhibited a MLCSL < 5mm. Ablating only the MRI-L+10mm or performing a ipsilateral hemi-ablation would leave residual GP4 in 14/59 (23.7%) and 11/59 (18.6%) of cases, respectively. CONCLUSIONS: Since a significant proportion of candidates for FA based on mpMRI and systematic biopsy will have pre-existing GP4EFD outside ablation templates, active surveillance of the untreated prostate is mandatory.

OBJECTIVE: To determine if multiparametric MRI (mpMRI) identifies significant apical disease, thereby informing decisions regarding preservation of the membranous urethra. MATERIALS AND METHODS: Men undergoing radical prostatectomy between January 2012 and June 2016 who underwent a 12-core transrectal-ultrasound guided systematic biopsy, preoperative 3-T MRI, and sectioning of the prostate specimen with tumor foci mapping were extracted from a single surgeon's prospective longitudinal outcomes database. Apical systematic biopsy vs. mpMRI lesion were compared for predicting aggressive tumor in the prostatic apex defined as Prostate Cancer Grade Group >1. RESULTS: Of the 100 men who met eligibility criteria, 43 (43%) exhibited aggressive prostate cancer in the distal 5mm of the apex. A Likert score > 2 in the apical one-third of the prostate was found to be more reliable than any cancer found on apical systematic biopsy at detecting aggressive cancer in the apex. On multivariate regression that included Likert score in the apex, age, PSA, prostate size, and presence of any cancer on apical biopsy, only Likert score (p=.005) and PSA (p=.025) were significant and independent predictors of aggressive cancer in the distal apex. CONCLUSION: MRI is superior to systematic biopsy at identifying aggressive prostate cancer within the distal prostatic apex and may be useful for planning the extent of apical preservation during prostatectomy.

CONTEXT: - Pathologic diagnosis of tumors in the genitourinary system can be challenging based on morphology alone, particularly when diagnostic material is limited, such as in core biopsies. Immunohistochemical stain can be a useful tool to aid in the diagnosis. OBJECTIVE: - To provide an update on practical applications and interpretation of immunohistochemical stains in the diagnosis of tumors in prostate, kidney, bladder, and testis. We particularly focus on difficult differential diagnoses, providing our insights in frequently encountered challenging situations. Commonly used immunohistochemical panels are discussed. DATA SOURCES: - Review of literature and our own experience. CONCLUSION: - Immunohistochemical stain is a valuable tool in the diagnosis of genitourinary tumors when appropriately used.

Distinguishing between indolent and aggressive prostate adenocarcinoma (PCa) remains a priority to accurately identify patients who need therapeutic intervention. SIN3B has been implicated in the initiation of senescence in vitro Here we show that in a mouse model of prostate cancer, SIN3B provides a barrier to malignant progression. SIN3B was required for PTEN-induced cellular senescence and prevented progression to invasive PCa. Furthermore, SIN3B was downregulated in human PCa correlating with upregulation of its target genes. Our results suggest a tumor suppressor function for SIN3B that limits PCa progression, with potential implications for the use of SIN3B and its target genes as candidate diagnostic markers to distinguish indolent from aggressive disease.