Peter C. Black

Discovery and Validation of a Prostate Cancer Genomic Classifier that Predicts Early Metastasis Following Radical Prostatectomy

Purpose Clinicopathologic features and biochemical recurrence are sensitive, but not specific, predictors of metastatic disease and lethal prostate cancer. We hypothesize that a genomic expression signature detected in the primary tumor represents true biological potential of aggressive disease and provides improved prediction of early prostate cancer metastasis. Methods A nested case-control design was used to select 639 patients from the Mayo Clinic tumor registry who underwent radical prostatectomy between 1987 and 2001. A genomic classifier (GC) was developed by modeling differential RNA expression using 1.4 million feature high-density expression arrays of men enriched for rising PSA after prostatectomy, including 213 who experienced early clinical metastasis after biochemical recurrence. A training set was used to develop a random forest classifier of 22 markers to predict for cases - men with early clinical metastasis after rising PSA. Performance of GC was compared to prognostic factors such as Gleason score and previous gene expression signatures in a withheld validation set. Results Expression profiles were generated from 545 unique patient samples, with median follow-up of 16.9 years. GC achieved an area under the receiver operating characteristic curve of 0.75 (0.67–0.83) in validation, outperforming clinical variables and gene signatures. GC was the only significant prognostic factor in multivariable analyses. Within Gleason score groups, cases with high GC scores experienced earlier death from prostate cancer and reduced overall survival. The markers in the classifier were found to be associated with a number of key biological processes in prostate cancer metastatic disease progression. Conclusion A genomic classifier was developed and validated in a large patient cohort enriched with prostate cancer metastasis patients and a rising PSA that went on to experience metastatic disease. This early metastasis prediction model based on genomic expression in the primary tumor may be useful for identification of aggressive prostate cancer.

Validation of a Genomic Classifier that Predicts Metastasis Following Radical Prostatectomy in an At Risk Patient Population

PURPOSE Patients with locally advanced prostate cancer after radical prostatectomy are candidates for secondary therapy. However, this higher risk population is heterogeneous. Many cases do not metastasize even when conservatively managed. Given the limited specificity of pathological features to predict metastasis, newer risk prediction models are needed. We report a validation study of a genomic classifier that predicts metastasis after radical prostatectomy in a high risk population. MATERIALS AND METHODS A case-cohort design was used to sample 1,010 patients after radical prostatectomy at high risk for recurrence who were treated from 2000 to 2006. Patients had preoperative prostate specific antigen greater than 20 ng/ml, Gleason 8 or greater, pT3b or a Mayo Clinic nomogram score of 10 or greater. Patients with metastasis at diagnosis or any prior treatment for prostate cancer were excluded from analysis. A 20% random sampling created a subcohort that included all patients with metastasis. We generated 22-marker genomic classifier scores for 219 patients with available genomic data. ROC and decision curves, competing risk and weighted regression models were used to assess genomic classifier performance. RESULTS The genomic classifier AUC was 0.79 for predicting 5-year metastasis after radical prostatectomy. Decision curves showed that the genomic classifier net benefit exceeded that of clinical only models. The genomic classifier was the predominant predictor of metastasis on multivariable analysis. The cumulative incidence of metastasis 5 years after radical prostatectomy was 2.4%, 6.0% and 22.5% in patients with low (60%), intermediate (21%) and high (19%) genomic classifier scores, respectively (p<0.001). CONCLUSIONS Results indicate that genomic information from the primary tumor can identify patients with adverse pathological features who are most at risk for metastasis and potentially lethal prostate cancer.

The impact of variant histology on the outcome of bladder cancer treated with curative intent

Patient risk stratification is essential for optimal management of patients with bladder cancer. Risk status determines the application and timing of therapeutic interventions such as repeat transurethral resection, intravesical chemo- and immunotherapy, systemic chemotherapy, and radical cystectomy. One key factor in such risk stratification appears to be the presence of variant histologic patterns in the bladder tumor. More than 90% of tumors are conventional urothelial carcinoma, and the rest consist of urothelial carcinoma with aberrant differentiation (squamous/glandular differentiation, small cell carcinoma, sarcomatoid carcinoma, and micropapillary carcinoma) or nonurothelial carcinoma (squamous cell carcinoma and adenocarcinoma). In this review, we focus on the implications of aberrant differentiation on the management of patients with bladder cancer. All of the variant histologies portend a worse prognosis than pure urothelial carcinoma. Although radical cystectomy remains the mainstay of treatment in all forms of bladder cancer, we highlight the use of neoadjuvant chemotherapy in patients with subtypes responsive to such therapy.

Patterns of Relapse in Patients With Clinical Stage I Testicular Cancer Managed With Active Surveillance

PURPOSE To evaluate the performance of active surveillance as a management strategy in broad populations and to inform the development of surveillance schedules by individual patient data regarding timing and type of relapse. METHODS Retrospective study including data from 2,483 clinical stage I (CSI) patients, 1,139 CSI nonseminoma and 1,344 CSI seminoma managed with active surveillance, with the majority treated between 1998 and 2010. Clinical outcomes including relapse and death, time distribution, extent of relapse and method of relapse detection observed on active surveillance were recorded. RESULTS Relapse occurred in 221 (19%) CSI-nonseminoma and 173 (13%) CSI-seminoma patients. Median time to relapse was 4 months (range, 2-61 months), 8 months (range, 2-77 months) and 14 months (range, 2-84 months) for lymphovascular invasion-positive CSI nonseminoma, lymphovascular invasion-negative CSI nonseminoma and CSI seminoma. Most relapses were observed within the first 2 years/3 years after orchiectomy for CSI nonseminoma (90%)/CSI seminoma (92%). Relapses were detected by computed tomography scan/tumor-markers in 87%/3% of seminoma recurrences, in 48%/38% of lymphovascular invasion-negative and 41%/61% of lymphovascular invasion-positive patients, respectively. 90% of CSI-nonseminoma and 99% of CSI-seminoma relapses exhibited International Germ Cell Collaborative Group good-risk features. Three patients with CSI nonseminoma died of disease (0.3%). One patient with CSI seminoma and two patients with CSI nonseminoma died because of treatment-related events. Overall, advanced disease was seen in both early- and late-relapse patients. All late recurrences were cured with standard therapy. Five-year disease-specific survival was 99.7% (95% CI, 99.24% to 99.93%). CONCLUSION Active surveillance for CSI testis cancer leads to excellent outcomes. The vast majority of relapses occur within 2 years of orchiectomy for CSI nonseminoma and within 3 years for CSI seminoma. Late and advanced stage relapse are rarely seen. These data may inform further refinement of rationally designed surveillance schedules.

Bladder cancer angiogenesis and metastasis—translation from murine model to clinical trial

In the majority of cases, death from bladder cancer results from metastatic disease. Understanding the closely linked mechanisms of invasion, metastasis and angiogenesis in bladder cancer has allowed us to develop new therapeutic strategies that harbor the promise of decisive improvements in patient survival. The essential link between cell based experiments and the translation of novel agents into human patients with bladder cancer is the animal model. With emphasis on the orthotopic xenograft model, this review outlines some key mechanisms relevant to angiogenesis and the development of metastasis in bladder cancer. We highlight especially pathways related to MMP-9, IL-8, VEGF and EGFR. Most commonly, expression patterns of these markers in patients have correlated to disease progression and patient survival, which has led to laboratory investigations of these markers and eventually novel targeted therapies that are translated back into the clinic by means of clinical trials. Although imperfect in their translatability into clinical efficacy, animal models remain a critical tool in bladder cancer research.

Sensitivity to Epidermal Growth Factor Receptor Inhibitor Requires E-Cadherin Expression in Urothelial Carcinoma Cells

Purpose: Epidermal growth factor receptor (EGFR) is an attractive target for the treatment of urothelial carcinoma, but a clinical response can be expected in only a small proportion of patients. The aim of this study was to define molecular markers of response to cetuximab therapy in a panel of urothelial carcinoma cell lines. Experimental Design: Eleven cell lines were investigated for antiproliferative response to cetuximab based on [3H]thymidine incorporation. A variety of markers, including EGFR expression, phosphorylation, and gene amplification, as well as the expression of other growth factor receptors, their ligands, and markers of epithelial-to-mesenchymal transition were investigated. Cohens κ statistic was used to estimate the agreement between response and expression of these markers. E-cadherin was silenced by small interfering RNA in two sensitive cell lines, and the effect on the response to cetuximab was measured. Results: We were able to identify a panel of relevant markers pertaining especially to alternate growth factor receptor expression and epithelial-to-mesenchymal transition that predicted response to cetuximab. The data suggested that expression of intact HER-4 (κ, 1.00; P = 0.008), E-cadherin (κ, 0.81; P = 0.015), and β-catenin (κ, 0.81; P = 0.015) and loss of expression of platelet-derived growth factor receptor β (κ, 0.57; P = 0.167) were associated with response to cetuximab therapy. Silencing E-cadherin in two sensitive cell lines reduced responsiveness to cetuximab in both (P < 0.001). Conclusions: A panel of predictive markers for cetuximab response has been established in vitro and is currently being evaluated in a prospective clinical trial of neoadjuvant EGFR-targeted therapy. Most importantly, E-cadherin seems to play a central role in modulation of EGFR response in urothelial carcinoma.

Impact of Molecular Subtypes in Muscle-invasive Bladder Cancer on Predicting Response and Survival after Neoadjuvant Chemotherapy

BACKGROUND An early report on the molecular subtyping of muscle-invasive bladder cancer (MIBC) by gene expression suggested that response to neoadjuvant chemotherapy (NAC) varies by subtype. OBJECTIVE To investigate the ability of molecular subtypes to predict pathological downstaging and survival after NAC. DESIGN, SETTING, AND PARTICIPANTS Whole transcriptome profiling was performed on pre-NAC transurethral resection specimens from 343 patients with MIBC. Samples were classified according to four published molecular subtyping methods. We developed a single-sample genomic subtyping classifier (GSC) to predict consensus subtypes (claudin-low, basal, luminal-infiltrated and luminal) with highest clinical impact in the context of NAC. Overall survival (OS) according to subtype was analyzed and compared with OS in 476 non-NAC cases (published datasets). INTERVENTION Gene expression analysis was used to assign subtypes. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Receiver-operating characteristics were used to determine the accuracy of GSC. The effect of GSC on survival was estimated by Cox proportional hazard regression models. RESULTS AND LIMITATIONS The models generated subtype calls in expected ratios with high concordance across subtyping methods. GSC was able to predict four consensus molecular subtypes with high accuracy (73%), and clinical significance of the predicted consensus subtypes could be validated in independent NAC and non-NAC datasets. Luminal tumors had the best OS with and without NAC. Claudin-low tumors were associated with poor OS irrespective of treatment regimen. Basal tumors showed the most improvement in OS with NAC compared with surgery alone. The main limitations of our study are its retrospective design and comparison across datasets. CONCLUSIONS Molecular subtyping may have an impact on patient benefit to NAC. If validated in additional studies, our results suggest that patients with basal tumors should be prioritized for NAC. We discovered the first single-sample classifier to subtype MIBC, which may be suitable for integration into routine clinical practice. PATIENT SUMMARY Different molecular subtypes can be identified in muscle-invasive bladder cancer. Although cisplatin-based neoadjuvant chemotherapy improves patient outcomes, we identified that the benefit is highest in patients with basal tumors. Our newly discovered classifier can identify these molecular subtypes in a single patient and could be integrated into routine clinical practice after further validation.

Multicenter Assessment of Neoadjuvant Chemotherapy for Muscle-invasive Bladder Cancer

BACKGROUND The efficacy of neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (BCa) was established primarily with methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC), with complete response rates (pT0) as high as 38%. However, because of the comparable efficacy with better tolerability of gemcitabine and cisplatin (GC) in patients with metastatic disease, GC has become the most commonly used regimen in the neoadjuvant setting. OBJECTIVE We aimed to assess real-world pathologic response rates to NAC with different regimens in a large, multicenter cohort. DESIGN, SETTING, AND PARTICIPANTS Data were collected retrospectively at 19 centers on patients with clinical cT2-4aN0M0 urothelial carcinoma of the bladder who received at least three cycles of NAC, followed by radical cystectomy (RC), between 2000 and 2013. INTERVENTION NAC and RC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The primary outcome was pathologic stage at cystectomy. Univariable and multivariable analyses were used to determine factors predictive of pT0N0 and ≤pT1N0 stages. RESULTS AND LIMITATIONS Data were collected on 935 patients who met inclusion criteria. GC was used in the majority of the patients (n=602; 64.4%), followed by MVAC (n=183; 19.6%) and other regimens (n=144; 15.4%). The rates of pT0N0 and ≤pT1N0 pathologic response were 22.7% and 40.8%, respectively. The rate of pT0N0 disease for patients receiving GC was 23.9%, compared with 24.5% for MVAC (p=0.2). There was no difference between MVAC and GC in pT0N0 on multivariable analysis (odds ratio: 0.89 [95% confidence interval, 0.61-1.34]; p=0.6). CONCLUSIONS Response rates to NAC were lower than those reported in prospective randomized trials, and we did not discern a difference between MVAC and GC. Without any evidence from randomized prospective trials, the best NAC regimen for invasive BCa remains to be determined. PATIENT SUMMARY There was no apparent difference in the response rates to the two most common presurgical chemotherapy regimens for patients with bladder cancer.

A Prospective Randomized Trial of Povidone-Iodine Prophylactic Cleansing of the Rectum Before Transrectal Ultrasound Guided Prostate Biopsy

PURPOSE Transrectal ultrasound guided prostate biopsy can lead to urinary tract infections in 3% to 11% and sepsis in 0.1% to 5% of patients. We investigated the efficacy of rectal cleansing with povidone-iodine before transrectal ultrasound guided prostate biopsy to reduce infectious complications. MATERIALS AND METHODS Between 2009 and 2011, 865 men were prospectively randomized to rectal cleansing (421) or no cleansing (444) before transrectal ultrasound guided prostate biopsy. Patients received ciprofloxacin prophylaxis and rectal swab cultures were obtained before transrectal ultrasound guided prostate biopsy. Patients completed a telephone interview 7 days after undergoing the biopsy. The primary end point was the rate of infectious complications, a composite end point of 1 or more of 1) fever greater than 38.0C, 2) urinary tract infection or 3) sepsis (standardized definition). Chi-square significance testing was performed for differences between groups and a multivariate analysis was performed to assess risk factors for infectious complications. RESULTS Infectious complications were observed in 31 (3.5%) patients, including 11 (2.6%) treated and 20 (4.5%) control patients (p = 0.15). Sepsis was observed in 4 (1.0%) treated and 7 (1.6%) control patients (p = 0.55). On multivariate analysis resistance to ciprofloxacin in the rectal swab culture (p = 0.002) and a history of taking ciprofloxacin in the 3 months preceding transrectal ultrasound guided prostate biopsy (p = 0.009) predicted infectious complications. CONCLUSIONS Rectal cleansing with povidone-iodine before transrectal ultrasound guided prostate biopsy was safe, but the 42% relative risk reduction of infectious complications was not statistically significant. Patients who have received ciprofloxacin within 3 months of transrectal ultrasound guided prostate biopsy should be considered for alternate prophylaxis or possibly a delay of biopsy beyond 3 months.

Molecular Markers of Urothelial Cancer and Their Use in the Monitoring of Superficial Urothelial Cancer

Multiple molecular markers have been described for use in bladder cancer patients. Some of these have been studied more extensively than others, and it is difficult for the clinician to maintain a perspective over the myriad findings that have been made. We have reviewed a selection of markers used for surveillance with an emphasis on clinical utility. The best studied markers and those with the most promising preliminary results were selected. Only studies that included surveillance for recurrence in patients with a history of bladder cancer were considered. Each marker is briefly described and its performance in monitoring bladder cancer patients is summarized. Several promising markers are available, although only four have obtained US Food and Drug Administration approval. The clinical applications that have been studied include replacement or reduction in the number of cystoscopies performed in the surveillance of bladder cancer patients, substitution for or complementary use with urinary cytology in the same setting, predicting disease recurrence and progression, and predicting and monitoring treatment response. None of the markers have been proved sensitive and specific enough to replace cystoscopy. Others, such as nuclear matrix protein 22 (NMP22) and UroVysion, appear to have some utility when used to complement or replace cytology. The other applications have not been adequately studied for any given marker. While multiple molecular markers exist for bladder cancer, their full clinical utility will not be realized until more multicenter prospective trials are conducted to verify their efficacy and safety in the monitoring of patients with superficial bladder cancer.