Stimulated Raman Histology Interpretation by Artificial Intelligence Provides Near-Real-Time Pathologic Feedback for Unprocessed Prostate Biopsies.

PURPOSE: Stimulated Raman histology is an innovative technology that generates real-time, high-resolution microscopic images of unprocessed tissue, significantly reducing prostate biopsy interpretation time. This study aims to evaluate the ability for an artificial intelligence convolutional neural network to interpretate prostate biopsy histologic images created with stimulated Raman histology. MATERIALS AND METHODS: Unprocessed, unlabeled prostate biopsies were prospectively imaged using a stimulated Raman histology microscope. Following stimulated Raman histology creation, the cores underwent standard pathological processing and interpretation by at least 2 genitourinary pathologists to establish a ground truth assessment. A network, trained on 303 prostate biopsies from 100 participants, was used to measure the accuracy, sensitivity, and specificity of detecting prostate cancer on stimulated Raman histology relative to conventional pathology. The performance of the artificial intelligence was evaluated on an independent 113-biopsy test set. RESULTS: Prostate biopsy images obtained through stimulated Raman histology can be generated within a time frame of 2 to 2.75 minutes. The artificial intelligence system achieved a rapid classification of prostate biopsies with cancer, with a potential identification time of approximately 1 minute. The artificial intelligence demonstrated an impressive accuracy of 96.5% in detecting prostate cancer. Moreover, the artificial intelligence exhibited a sensitivity of 96.3% and a specificity of 96.6%. CONCLUSIONS: Stimulated Raman histology generates microscopic images capable of accurately identifying prostate cancer in real time, without the need for sectioning or tissue processing. These images can be interpreted by artificial intelligence, providing physicians with near-real-time pathological feedback during the diagnosis or treatment of prostate cancer.

Does normalisation improve the diagnostic performance of apparent diffusion coefficient values for prostate cancer assessment? A blinded independent-observer evaluation.

AIM: To evaluate the performance of normalised apparent diffusion coefficient (ADC) values for prostate cancer assessment when performed by independent observers blinded to histopathology findings. MATERIALS AND METHODS: Fifty-eight patients undergoing 3 T phased-array coil magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI; maximal b-value 1000 s/mm(2)) before prostatectomy were included. Two radiologists independently evaluated the images, unaware of the histopathology findings. Regions of interest (ROIs) were drawn within areas showing visually low ADC within the peripheral zone (PZ) and transition zone (TZ) bilaterally. ROIs were also placed within regions in both lobes not suspicious for tumour, allowing computation of normalised ADC (nADC) ratios between suspicious and non-suspicious regions. The diagnostic performance of ADC and nADC were compared. RESULTS: For PZ tumour detection, ADC achieved significantly higher area under the receiver operating characteristic curve (AUC; p=0.026) and specificity (p=0.021) than nADC for reader 1, and significantly higher AUC (p=0.025) than nADC for reader 2. For TZ tumour detection, nADC achieved significantly higher specificity (p=0.003) and accuracy (p=0.004) than ADC for reader 2. For PZ Gleason score >3+3 tumour detection, ADC achieved significantly higher AUC (p=0.003) and specificity (p=0.005) than nADC for reader 1, and significantly higher AUC (p=0.023) than nADC for reader 2. For TZ Gleason score >3+3 tumour detection, ADC achieved significantly higher specificity (p=0.019) than nADC for reader 1. CONCLUSION: In contrast to prior studies performing unblinded evaluations, ADC was observed to outperform nADC overall for two independent observers blinded to the histopathology findings. Therefore, although strategies to improve the utility of ADC measurements in prostate cancer assessment merit continued investigation, caution is warranted when applying normalisation to improve diagnostic performance in clinical practice.

Assessment of change in prostate volume and shape following surgical resection through co-registration of in-vivo MRI and fresh specimen ex-vivo MRI.

AIM: To compare the size and shape of the prostate between in-vivo and fresh ex-vivo magnetic resonance imaging (MRI), in order to quantify alterations in the prostate resulting from surgical resection. MATERIAL AND METHOD: Ten patients who had undergone 3 T prostate MRI using a phased-array coil and who were scheduled for prostatectomy were included in this prospective study. The ex-vivo specimen underwent MRI prior to formalin fixation or any other histopathological processing. Prostate volume in vivo and ex vivo was assessed using planimetry. Prostate shape was assessed by calculating ratios between the diameters of the prostate in all three dimensions. RESULTS: Mean prostate volume was significantly smaller ex vivo than in vivo (39.7 ± 18.6 versus 50.8 ± 26.8 cm(3); p = 0.008), with an average change in volume of -19.5%. The right-to-left (RL)/anteroposterior (AP) ratio of the prostate, representing the shape of the prostate within its axial plane, was significantly larger ex vivo than in vivo (1.33 ± 0.14 versus 1.21 ± 0.12; p = 0.015), with an average percent change in RL/AP ratio of the prostate of +12.2%. There was no significant difference between in-vivo and ex-vivo acquisitions in terms of craniocaudal (CC)/AP (p = 0.963, median change = -2.1%) or RL/CC (p = 0.265, median change = +1.3%) ratios. CONCLUSION: The observed volume and shape change following resection has not previously been assessed by comparison of in-vivo and fresh ex-vivo MRI and likely represents loss of vascularity and of connective tissue attachments in the ex-vivo state. These findings have implications for co-registration platforms under development to facilitate improved understanding of the accuracy of MRI in spatial localization of prostate tumours.

Preliminary experience with a novel method of three-dimensional co-registration of prostate cancer digital histology and in vivo multiparametric MRI.

AIM: To assess a novel method of three-dimensional (3D) co-registration of prostate cancer digital histology and in-vivo multiparametric magnetic resonance imaging (mpMRI) image sets for clinical usefulness. MATERIAL AND METHODS: A software platform was developed to achieve 3D co-registration. This software was prospectively applied to three patients who underwent radical prostatectomy. Data comprised in-vivo mpMRI [T2-weighted, dynamic contrast-enhanced weighted images (DCE); apparent diffusion coefficient (ADC)], ex-vivo T2-weighted imaging, 3D-rebuilt pathological specimen, and digital histology. Internal landmarks from zonal anatomy served as reference points for assessing co-registration accuracy and precision. RESULTS: Applying a method of deformable transformation based on 22 internal landmarks, a 1.6 mm accuracy was reached to align T2-weighted images and the 3D-rebuilt pathological specimen, an improvement over rigid transformation of 32% (p = 0.003). The 22 zonal anatomy landmarks were more accurately mapped using deformable transformation than rigid transformation (p = 0.0008). An automatic method based on mutual information, enabled automation of the process and to include perfusion and diffusion MRI images. Evaluation of co-registration accuracy using the volume overlap index (Dice index) met clinically relevant requirements, ranging from 0.81-0.96 for sequences tested. Ex-vivo images of the specimen did not significantly improve co-registration accuracy. CONCLUSION: This preliminary analysis suggests that deformable transformation based on zonal anatomy landmarks is accurate in the co-registration of mpMRI and histology. Including diffusion and perfusion sequences in the same 3D space as histology is essential further clinical information. The ability to localize cancer in 3D space may improve targeting for image-guided biopsy, focal therapy, and disease quantification in surveillance protocols.

Phosphorylation of the androgen receptor by PIM1 in hormone refractory prostate cancer.

Integration of cellular signaling pathways with androgen receptor (AR) signaling can be achieved through phosphorylation of AR by cellular kinases. However, the kinases responsible for phosphorylating the AR at numerous sites and the functional consequences of AR phosphorylation are only partially understood. Bioinformatic analysis revealed AR serine 213 (S213) as a putative substrate for PIM1, a kinase overexpressed in prostate cancer. Therefore, phosphorylation of AR serine 213 by PIM1 was examined using a phosphorylation site-specific antibody. Wild-type PIM1, but not catalytically inactive PIM1, specifically phosphorylated AR but not an AR serine-to-alanine mutant (S213A). In vitro kinase assays confirmed that PIM1 can phosphorylate AR S213 in a ligand-independent manner and cell type-specific phosphorylation was observed in prostate cancer cell lines. Upon PIM1 overexpression, AR phosphorylation was observed in the absence of hormone and was further increased in the presence of hormone in LNCaP, LNCaP-abl and VCaP cells. Moreover, phosphorylation of AR was reduced in the presence of PIM kinase inhibitors. An examination of AR-mediated transcription showed that reporter gene activity was reduced in the presence of PIM1 and wild-type AR, but not S213A mutant AR. Androgen-mediated transcription of endogenous PSA, Nkx3.1 and IGFBP5 was also decreased in the presence of PIM1, whereas IL6, cyclin A1 and caveolin 2 were increased. Immunohistochemical analysis of prostate cancer tissue microarrays showed significant P-AR S213 expression that was associated with hormone refractory prostate cancers, likely identifying cells with catalytically active PIM1. In addition, prostate cancers expressing a high level of P-AR S213 were twice as likely to be from biochemically recurrent cancers. Thus, AR phosphorylation by PIM1 at S213 impacts gene transcription and is highly prevalent in aggressive prostate cancer.

Impact of delay after biopsy and post-biopsy haemorrhage on prostate cancer tumour detection using multi-parametric MRI: a multi-reader study.

AIM: To assess impact of haemorrhage and delay after biopsy on prostate tumour detection using multi-parametric (MP) magnetic resonance imaging (MRI) assessment. MATERIALS AND METHODS: Forty-four patients underwent prostate MRI at 1.5 T using a pelvic phased-array coil, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging, before prostatectomy. Three radiologists independently reviewed images during four sessions [T2WI, DWI, DCE, and all parameters combined (MP-MRI)] to assess for tumour in each sextant. In a separate session, readers reviewed T1WI to score the extent of haemorrhage per sextant. Accuracy was assessed using logistic regression for correlated data. RESULTS: There was no significant difference in accuracy between readers for any session (p ≥ 0.166), and results were averaged across the three readers for remaining comparisons. Accuracy was significantly greater for MP-MRI than for any parameter alone (p ≤ 0.020). For T2WI alone, there was a trend toward decreased sensitivity in sextants with extensive haemorrhage (p = 0.072). However, accuracy, sensitivity, and specificity were otherwise similar for sextants with and without extensive haemorrhage for all sessions (p = 0.192-0.934). No session showed a significant improvement in accuracy, sensitivity, or specificity in cases with delay after biopsy of over 4 weeks compared with shorter delay. CONCLUSION: Extensive haemorrhage and short delay after biopsy did not negatively impact accuracy for tumour detection using MP-MRI. Further studies using MP-MRI protocols and interpretation schemes from other institutions are required to confirm these observations.

MRI appearance of massive renal replacement lipomatosis in the absence of renal calculus disease.

Renal replacement lipomatosis is a rare benign entity in which extensive fibrofatty proliferation of the renal sinus is associated with marked renal atrophy. In this report, we present a case of massive renal replacement lipomatosis demonstrated on MRI. The presentation was atypical given an absence of associated renal calculus disease, and an initial CT scan was interpreted as suspicious for a liposarcoma. The differential diagnosis and key MRI findings that served to establish this specific diagnosis are reviewed. Histopathological correlation is also presented, as the patient underwent nephroureterectomy.

Contemporary clinical management of isolated high-grade prostatic intraepithelial neoplasia.

High-grade prostatic intraepithelial neoplasia (HGPIN) is a premalignant lesion associated with increased risk of coexistent cancer or delayed progression to carcinoma. Extended biopsy schemes have improved the ability to rule out concurrent cancers, increased the detection of isolated HGPIN and removed the routine necessity for immediate repeat biopsy. As the natural history of HGPIN is poorly defined, and no non-invasive marker allows monitoring of progression to cancer, routine delayed interval biopsy should be considered in all patients. In this article, we present an overview of the existing literature on HGPIN and a proposed strategy for clinical management.

Adjuvant androgen deprivation therapy augments cure and long-term cancer control in men with poor prognosis, nonmetastatic prostate cancer.

Historically, adjuvant androgen deprivation therapy has been viewed as a palliative treatment option for patients with poor-prognosis non-metastatic prostate cancer. In addition, guidelines from bodies such as the European Association of Urology and American Society for Clinical Oncology do not specifically categorize adjuvant hormonal therapy as being curative in intent. We propose that adjuvant androgen deprivation therapy should now be classified as a treatment of curative intent in patients with poor-prognosis, non-metastatic prostate cancer. By applying a carefully considered definition of cure (based on long-term (10- to 15-year) disease-free survival curves) to the findings from randomized controlled clinical trials that have studied adjuvant hormonal treatments in non-metastatic prostate cancer, we challenged whether this viewpoint should now be considered redundant. According to our review of relevant studies and our definition of cure, goserelin appears to augment cure in a sizeable proportion of men with poor-prognosis non-metastatic prostate cancer when given adjuvant to radical prostatectomy or radiotherapy. Across several trials, the relevant survival curves for the goserelin-treated population became indefinitely flat after long-term follow-up. This indicates that these patients have a mortality risk comparable to the general population without prostate cancer. On the basis of the evidence presented within this review, we believe that, given it can control disease for a long period of time, adjuvant goserelin should be reclassified as a treatment of curative intent for patients with poor-prognosis non-metastatic prostate cancer.

Genetic counseling for prostate cancer risk.

Major risk factors for developing prostate cancer, including positive family history and African-American ethnicity, can be quantified for genetic counseling. Factors increasing familial risk for prostate cancer are closer degree of kinship, number of affected relatives, and early age of onset (< 50 years) among the affected relatives. Genetic testing may be useful for modification of risk, but currently should be performed only within the context of a well-designed research study that will determine penetrance and genotype-phenotype correlation of specific mutations. Even in the absence of genetic testing, African-American men and men with a strong family history of prostate cancer may opt to initiate screening by prostate specific antigen (PSA) and digital rectal exam (DRE) screening at age 40.

Is repeat prostate biopsy for high-grade prostatic intraepithelial neoplasia necessary after routine 12-core sampling?

OBJECTIVES: To determine whether repeat biopsy is necessary when the diagnosis of high-grade prostatic intraepithelial neoplasia (HGPIN) is made with a 12-core biopsy. Repeated biopsy has been recommended for individuals with HGPIN noted on sextant prostate biopsy because of the high likelihood of cancer detection. Recently, we have recommended the routine use of 12 cores, rather than 6, to improve cancer detection. METHODS: The charts of all patients undergoing prostate biopsy during a 2-year period at the Manhattan Veterans Administration Medical Center were reviewed. Patients diagnosed with HGPIN on a 12-core biopsy were identified, and those undergoing a repeat 12-core biopsy within 1 year of the initial biopsy were evaluated to determine the rate of cancer detection. RESULTS: A total of 619 men underwent biopsy during the study period. Of 103 men diagnosed with HGPIN, 43 underwent a repeat biopsy within 1 year at the discretion of the managing urologist. The mean age and median prostate-specific antigen level of those undergoing a repeat biopsy was 65.5 years and 5.37 ng/mL, respectively. At the time of the repeat biopsy, 1 patient was found to have cancer (2.3%), 20 had HGPIN (46.5%), 20 had benign pathologic findings (46.5%), and 1 patient (2.3%) had atypical small acinar proliferation. CONCLUSIONS: A repeat biopsy after the diagnosis of HGPIN on 12-core prostate biopsy rarely results in cancer detection. In the absence of other factors increasing the suspicion of cancer, immediate repeat biopsy for HGPIN diagnosed on a 12-core biopsy is unnecessary.

Androgen stimulated cellular proliferation in the human prostate cancer cell line LNCaP is associated with reduced retinoblastoma protein expression.

To elucidate the mechanism of androgen-dependent cellular proliferation in prostate cancer, androgen-dependent alterations of individual cell cycle regulatory proteins in the androgen-sensitive prostate cancer cell line LNCaP were evaluated. LNCaP cells were deprived of androgens by culture in steroid-depleted media for 5 days, which resulted in the maximal accumulation of cells in G(0)/G(1) phase of the cell cycle. The mitogenic concentration of the synthetic androgen R1881 was established as 0.1 nM using cell proliferation assay. Protein and mRNA levels of particular cyclins, cyclin-dependent kinases (Cdks), cyclin-dependent kinase inhibitors (Ckis), and the retinoblastoma proteins (Rb) were assessed. Androgen stimulation resulted in a post-transcriptional reduction in Rb protein levels, an increase in Rb phosphorylation at serine 780 and an accumulation of high molecular weight Rb protein species. Androgen stimulation also induced the expression of the Cdk2 and Cdk1 as well as their regulatory partners, cyclin A and cyclin B, resulting in a corresponding increase in cyclin A/Cdk2 activity in vitro. Pulse-chase showed decreased Rb protein stability in androgen-treated LNCaP cells. Collectively, our findings suggest a novel mechanism of androgen-dependent prostate cancer growth in which androgen stimulation results in decreased Rb protein expression in LNCaP cells. The observation of decreased Rb protein stability in the setting of increased phosphorylation supports the concept of phosphorylation mediated protein degradation. We propose that the observed reduction in Rb protein level occurs through Rb degradation via the ubiquitin/proteasome pathway, and is preceded by selective Rb phosphorylation by cyclin A/Cdk2 and cyclin B/Cdk1.

Volume-specific cutoffs are necessary for reproducible application of prostate-specific antigen density of the transition zone in prostate cancer detection.

OBJECTIVES: To determine the effect of prostate volume on the specificity of prostate-specific antigen density (PSAD) and PSAD of the transition zone (PSA-TZ) in the detection of prostate cancer. METHODS: Between February 1994 and April 1998, transrectal ultrasound-guided prostate needle biopsies were performed in 235 men with serum prostate-specific antigen (PSA) levels between 4.0 and 10.0 ng/mL. The PSAD and PSA-TZ specificities were calculated at 95% sensitivity cutoff levels generated from the whole group, as well as from cohorts stratified by transition zone index or prostate volume. RESULTS: Statistical significance was noted between the benign (n = 176) and prostate cancer (n = 59) groups for all tested PSA parameters. At 95% sensitivity, PSA-TZ carried a specificity of 37.5% compared with 29.6% for PSAD. When applying a single 95% sensitivity cutoff derived from the entire group to individual volume-stratified cohorts, the specificity decreased to 0% in glands less than 30 g in size. A 95% sensitivity PSA-TZ cutoff generated individually for volume-stratified cohorts of glands less than 30, 30 to 40, and 40 to 60 g resulted in more consistent specificity of 28.2%, 35.2%, and 45.7% for each cohort, respectively. CONCLUSIONS: Unlike whole group-derived cutoffs, the use of volume-specific PSA-TZ cutoffs allows consistently high specificity in all volume-stratified cohorts. The discrepancies in the PSA-TZ and PSAD specificities in published reports are likely due to the application of published cutoffs to populations of differing prostate volumes. The use of volume-specific cutoffs results in reproducible specificity in populations with differing prostate volume distribution, and thereby definitively resolves the differences in PSA-TZ specificity reported in published reports.

Does site specific labeling of sextant biopsy cores predict the site of extracapsular extension in radical prostatectomy surgical specimen.

PURPOSE: We determine whether site specific labeling of sextant prostate biopsy cores predicts the site of extracapsular extension in a radical prostatectomy specimen, thereby justifying increased cost of pathological evaluation. MATERIALS AND METHODS: Between January 1994 and December 1997, 407 radical prostatectomies were performed at our institution by a single surgeon (H. L.). Surgical specimens showing extracapsular extension were examined by a single pathologist (J. M.) to identify the site of extension. Several different methods of submitting transrectal ultrasound guided biopsy cores were used since the majority of cases did not undergo biopsy at our institution. In 243 cases sextant biopsies were labeled right versus left. Of these cases 103 specimen cores were individually labeled. The ability of the positive biopsy core location to predict the location of extracapsular extension in the surgical specimen was determined. Univariate and multivariate logistic regression analyses were performed to assess the ability of biopsy core characteristics, including Gleason score, percentage of cancer in the core, core location and number of positive cores in the specimen, to predict the site of extracapsular extension. A similar analysis was performed for the 243 cases with right versus left core labeling. RESULTS: The positive predictive value was 8.9+/-2.2% for a single positive core to identify the location of extracapsular extension correctly in the individually labeled core cases. The absence of cancer in a sextant biopsy had a negative predictive value of 96.9+/-1.4%. The overall sensitivity was 59.4+/-3.8% for a positive biopsy core. In the right versus left core cases the positive predictive value was 12.9+/-3.0% with a sensitivity of 85.1+/-3.2%. In an individual core Gleason score 8 or greater and/or cancer in more than 50% of tissue enhanced the positive predictive value but not to a clinically useful level. Multivariate logistic regression identified Gleason score, number of positive ipsilateral cores and base position of the positive biopsy as the most predictive variables for the site of extracapsular extension. CONCLUSIONS: When submitting biopsy specimens by individually labeled core or right versus left core, the positive predictive value of an individual positive core for the location of extracapsular extension is not sufficient to guide the surgical decision to spare or excise a neurovascular bundle. Therefore, the clinical information provided by individually labeled or right versus left core labeling does not justify the increased associated costs.

Prospects for gene therapy in human prostate cancer.

Prostate cancer is the most common neoplasm in men and a significant cause of mortality in affected patients. Despite significant advances, current methods of treatment are effective only in the absence of metastatic disease. Gene therapy offers a renewed hope of using the differential characteristics of normal and malignant tissue in constructing treatment strategies. Several clinical trials in prostate cancer gene therapy are currently under way, using immunomodulatory genes, anti-oncogenes, tumor suppressor genes and suicide genes. A continued understanding of the etiological mechanisms involved in the establishment and progression of prostate cancer, along with advances in gene therapy technology, should make gene therapy for prostate cancer therapeutically valuable in the future.