Ashley E. Ross

Prostate-Specific Antigen Kinetics During Follow-Up Are an Unreliable Trigger for Intervention in a Prostate Cancer Surveillance Program

PURPOSE To assess the predictive ability of prostate-specific antigen (PSA) velocity (PSAV) and doubling time (PSADT) for biopsy progression and adverse pathology at prostatectomy among men with low-risk prostate cancer enrolled on an active-surveillance program. METHODS We evaluated 290 men who met criteria for active surveillance (ie, PSA density < 0.15 ng/mL/cm(3) and Gleason score < or = 6 with no pattern > or = 4, involving < or = 2 cores with cancer, and < or = 50% involvement of any core by cancer) with two or more serial PSA measurements after diagnosis from 1994 to 2008. Follow-up included twice-yearly digital rectal exam and PSA measurements and yearly surveillance biopsy. Treatment was recommended for biopsy progression (ie, Gleason score > or = 7, or > 2 positive cores, or > 50% core involvement). Sensitivity and specificity of postdiagnostic PSAV and PSADT were explored by using receiver operating characteristic (ROC) analysis. RESULTS Overall, 188 (65%) men remained on active surveillance, and 102 (35%) developed biopsy progression at a median follow-up of 2.9 years. PSADT was not significantly associated with subsequent adverse biopsy findings (P = .83), and PSAV was marginally significant (P = .06). No PSAV or PSADT cut point had both high sensitivity and specificity (area under the curve, 0.61 and 0.59, respectively) for biopsy progression. In those who eventually underwent radical prostatectomy, PSAV (P = .79) and PSADT (P = .87) were not associated with the presence of unfavorable surgical pathology. CONCLUSION Postdiagnostic PSA kinetics do not reliably predict adverse pathology and should not be used to replace annual surveillance biopsy for monitoring men on active surveillance.

African American Men With Very Low–Risk Prostate Cancer Exhibit Adverse Oncologic Outcomes After Radical Prostatectomy: Should Active Surveillance Still Be an Option for Them?

PURPOSE Active surveillance (AS) is a treatment option for men with very low-risk prostate cancer (PCa); however, favorable outcomes achieved for men in AS are based on cohorts that under-represent African American (AA) men. To explore whether race-based health disparities exist among men with very low-risk PCa, we evaluated oncologic outcomes of AA men with very low-risk PCa who were candidates for AS but elected to undergo radical prostatectomy (RP). PATIENTS AND METHODS We studied 1,801 men (256 AA, 1,473 white men, and 72 others) who met National Comprehensive Cancer Network criteria for very low-risk PCa and underwent RP. Presenting characteristics, pathologic data, and cancer recurrence were compared among the groups. Multivariable modeling was performed to assess the association of race with upgrading and adverse pathologic features. RESULTS AA men with very low-risk PCa had more adverse pathologic features at RP and poorer oncologic outcomes. AA men were more likely to experience disease upgrading at prostatectomy (27.3% v 14.4%; P < .001), positive surgical margins (9.8% v 5.9%; P = .02), and higher Cancer of the Prostate Risk Assessment Post-Surgical scoring system (CAPRA-S) scores. On multivariable analysis, AA race was an independent predictor of adverse pathologic features (odds ratio, [OR], 3.23; P = .03) and pathologic upgrading (OR, 2.26; P = .03). CONCLUSION AA men with very low-risk PCa who meet criteria for AS but undergo immediate surgery experience significantly higher rates of upgrading and adverse pathology than do white men and men of other races. AA men with very low-risk PCa should be counseled about increased oncologic risk when deciding among their disease management options.

Pathological examination of radical prostatectomy specimens in men with very low risk disease at biopsy reveals distinct zonal distribution of cancer in black American men

PURPOSE Of men with very low risk prostate cancer at biopsy recent evidence shows that black American men are at greater risk for adverse oncologic outcomes after radical prostatectomy. We studied radical prostatectomy specimens from black and white men at very low risk to determine whether there are systematic pathological differences. MATERIALS AND METHODS Radical prostatectomy specimens were evaluated in men with National Comprehensive Cancer Network® (NCCN) very low risk prostate cancer. At diagnosis all men underwent extended biopsy sampling (10 or more cores) and were treated in the modern Gleason grade era. We analyzed tumor volume, grade and location in 87 black and 89 white men. For each specimen the dominant nodule was defined as the largest tumor with the highest grade. RESULTS Compared to white men, black men were more likely to have significant prostate cancer (61% vs 29%), Gleason 7 or greater (37% vs 11%, each p <0.001) and a volume of greater than 0.5 cm(3) (45% vs 21%, p = 0.001). Dominant nodules in black men were larger (median 0.28 vs 0.13 cm(3), p = 0.002) and more often anterior (51% vs 29%, p = 0.003). In men who underwent pathological upgrading the dominant nodule was also more frequently anterior in black than in white men (59% vs 0%, p = 0.001). CONCLUSIONS Black men with very low risk prostate cancer at diagnosis have a significantly higher prevalence of anterior cancer foci that are of higher grade and larger volume. Enhanced imaging or anterior zone sampling may detect these significant anterior tumors, improving the outcome in black men considering active surveillance.

Tissue-based Genomics Augments Post-prostatectomy Risk Stratification in a Natural History Cohort of Intermediate- and High-Risk Men.

BACKGROUND Radical prostatectomy (RP) is a primary treatment option for men with intermediate- and high-risk prostate cancer. Although many are effectively cured with local therapy alone, these men are by definition at higher risk of adverse pathologic features and clinical disease recurrence. It has been shown that the Decipher test predicts metastatic progression in cohorts that received adjuvant and salvage therapy following RP. OBJECTIVE To evaluate the Decipher genomic classifier in a natural history cohort of men at risk who received no additional treatment until the time of metastatic progression. DESIGN, SETTING, AND PARTICIPANTS Retrospective case-cohort design for 356 men who underwent RP between 1992 and 2010 at intermediate or high risk and received no additional treatment until the time of metastasis. Participants met the following criteria: (1) Cancer of the Prostate Risk Assessment postsurgical (CAPRA-S) score ≥3; (2) pathologic Gleason score ≥7; and (3) post-RP prostate-specific antigen nadir <0.2 ng/ml. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The primary endpoint was defined as regional or distant metastases. Time-dependent receiver operating characteristic (ROC) curves, extension of decision curve analysis to survival data, and univariable and multivariable Cox proportional-hazards models were used to measure the discrimination, net benefit, and prognostic potential of genomic and pathologic risk factors. Cumulative incidence curves were constructed using Fine-Gray competing-risks analysis with appropriate weighting of the controls to account for the case-cohort study design. RESULTS AND LIMITATIONS Ninety six patients had unavailable tumor blocks or failed microarray quality control. Decipher scores were then obtained for 260 patients, of whom 99 experienced metastasis. Decipher correlated with increased cumulative incidence of biochemical recurrence, metastasis, and prostate cancer-specific mortality (p<0.01). The cumulative incidence of metastasis was 12% and 47% for patients with low and high Decipher scores, respectively, at 10 yr after RP. Decipher was independently prognostic of metastasis in multivariable analysis (hazard ratio 1.26 per 10% increase; p<0.01). Decipher had a c-index of 0.76 and increased the c-index of Eggener and CAPRA-S risk models from 0.76 and 0.77 to 0.86 and 0.87, respectively, at 10 yr after RP. Although the cohort was large, the single-center retrospective design is an important limitation. CONCLUSIONS In a patient population that received no adjuvant or salvage therapy after prostatectomy until metastatic progression, higher Decipher scores correlated with clinical events, and inclusion of Decipher scores improved the prognostic performance of validated clinicopathologic risk models. These results confirm the utility already reported for Decipher. PATIENT SUMMARY The Decipher test improves identification of patients most at risk of metastatic progression and death from prostate cancer after radical prostatectomy.

A genomic classifier predicting metastatic disease progression in men with biochemical recurrence after prostatectomy

Background:Due to their varied outcomes, men with biochemical recurrence (BCR) following radical prostatectomy (RP) present a management dilemma. Here, we evaluate Decipher, a genomic classifier (GC), for its ability to predict metastasis following BCR.Methods:The study population included 85 clinically high-risk patients who developed BCR after RP. Time-dependent receiver operating characteristic (ROC) curves, weighted Cox proportional hazard models and decision curves were used to compare GC scores to Gleason score (GS), PSA doubling time (PSAdT), time to BCR (ttBCR), the Stephenson nomogram and CAPRA-S for predicting metastatic disease progression. All tests were two-sided with a type I error probability of 5%.Results:GC scores stratified men with BCR into those who would or would not develop metastasis (8% of patients with low versus 40% with high scores developed metastasis, P<0.001). The area under the curve for predicting metastasis after BCR was 0.82 (95% CI, 0.76–0.86) for GC, compared to GS 0.64 (0.58–0.70), PSAdT 0.69 (0.61–0.77) and ttBCR 0.52 (0.46–0.59). Decision curve analysis showed that GC scores had a higher overall net benefit compared to models based solely on clinicopathologic features. In multivariable modeling with clinicopathologic variables, GC score was the only significant predictor of metastasis (P=0.003).Conclusions:When compared to clinicopathologic variables, GC better predicted metastatic progression among this cohort of men with BCR following RP. While confirmatory studies are needed, these results suggest that use of GC may allow for better selection of men requiring earlier initiation of treatment at the time of BCR.

Mimicry of pre-B cell receptor signaling by activation of the tyrosine kinase Blk.

During B lymphoid ontogeny, assembly of the pre–B cell receptor (BCR) is a principal developmental checkpoint at which several Src-related kinases may play redundant roles. Here the Src-related kinase Blk is shown to effect functions associated with the pre-BCR. B lymphoid expression of an active Blk mutant caused proliferation of B progenitor cells and enhanced responsiveness of these cells to interleukin 7. In mice lacking a functional pre-BCR, active Blk supported maturation beyond the pro–B cell stage, suppressed VH to DJH rearrangement, relieved selection for productive heavy chain rearrangement, and stimulated κ rearrangement. These alterations were accompanied by tyrosine phosphorylation of immunoglobulin β and Syk, as well as changes in gene expression consistent with developmental maturation. Thus, sustained activation of Blk induces responses normally associated with the pre-BCR.

Characterization of 1577 primary prostate cancers reveals novel biological and clinicopathologic insights into molecular subtypes

BACKGROUND Prostate cancer (PCa) molecular subtypes have been defined by essentially mutually exclusive events, including ETS gene fusions (most commonly involving ERG) and SPINK1 overexpression. Clinical assessment may aid in disease stratification, complementing available prognostic tests. OBJECTIVE To determine the analytical validity and clinicopatholgic associations of microarray-based molecular subtyping. DESIGN, SETTING, AND PARTICIPANTS We analyzed Affymetrix GeneChip expression profiles for 1577 patients from eight radical prostatectomy cohorts, including 1351 cases assessed using the Decipher prognostic assay (GenomeDx Biosciences, San Diego, CA, USA) performed in a laboratory with Clinical Laboratory Improvements Amendment certification. A microarray-based (m-) random forest ERG classification model was trained and validated. Outlier expression analysis was used to predict other mutually exclusive non-ERG ETS gene rearrangements (ETS(+)) or SPINK1 overexpression (SPINK1(+)). OUTCOME MEASUREMENTS Associations with clinical features and outcomes by multivariate logistic regression analysis and receiver operating curves. RESULTS AND LIMITATIONS The m-ERG classifier showed 95% accuracy in an independent validation subset (155 samples). Across cohorts, 45% of PCas were classified as m-ERG(+), 9% as m-ETS(+), 8% as m-SPINK1(+), and 38% as triple negative (m-ERG(-)/m-ETS(-)/m-SPINK1(-)). Gene expression profiling supports three underlying molecularly defined groups: m-ERG(+), m-ETS(+), and m-SPINK1(+)/triple negative. On multivariate analysis, m-ERG(+) tumors were associated with lower preoperative serum prostate-specific antigen and Gleason scores, but greater extraprostatic extension (p<0.001). m-ETS(+) tumors were associated with seminal vesicle invasion (p=0.01), while m-SPINK1(+)/triple negative tumors had higher Gleason scores and were more frequent in Black/African American patients (p<0.001). Clinical outcomes were not significantly different among subtypes. CONCLUSIONS A clinically available prognostic test (Decipher) can also assess PCa molecular subtypes, obviating the need for additional testing. Clinicopathologic differences were found among subtypes based on global expression patterns. PATIENT SUMMARY Molecular subtyping of prostate cancer can be achieved using extra data generated from a clinical-grade, genome-wide expression-profiling prognostic assay (Decipher). Transcriptomic and clinical analysis support three distinct molecular subtypes: (1) m-ERG(+), (2) m-ETS(+), and (3) m-SPINK1(+)/triple negative (m-ERG(-)/m-ETS(-)/m-SPINK1(-)). Incorporation of subtyping into a clinically available assay may facilitate additional applications beyond routine prognosis.

Gene expression pathways of high grade localized prostate cancer.

Despite advances in screening and local therapy, prostate cancer remains the second most common cause of cancer related death among American men, with those having high grade disease being at highest risk for prostate cancer mortality. Here we identify the genes and cellular pathways that distinguish high grade from low grade pathologically localized prostate cancer.

Comparison of Prostate-Specific Membrane Antigen–Based 18F-DCFBC PET/CT to Conventional Imaging Modalities for Detection of Hormone-Naïve and Castration-Resistant Metastatic Prostate Cancer

Conventional imaging modalities (CIMs) have limited sensitivity and specificity for detection of metastatic prostate cancer. We examined the potential of a first-in-class radiofluorinated small-molecule inhibitor of prostate-specific membrane antigen (PSMA), N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-18F-fluorobenzyl-l-cysteine (18F-DCFBC), to detect metastatic hormone-naïve (HNPC) and castration-resistant prostate cancer (CRPC). Methods: Seventeen patients were prospectively enrolled (9 HNPC and 8 CRPC); 16 had CIM evidence of new or progressive metastatic prostate cancer and 1 had high clinical suspicion of metastatic disease. 18F-DCFBC PET/CT imaging was obtained with 2 successive PET scans starting at 2 h after injection. Patients were imaged with CIM at approximately the time of PET. A lesion-by-lesion analysis of PET to CIM was performed in the context of either HNPC or CRPC. The patients were followed with available clinical imaging as a reference standard to determine the true nature of identified lesions on PET and CIM. Results: On the lesion-by-lesion analysis, 18F-DCFBC PET was able to detect a larger number of lesions (592 positive with 63 equivocal) than CIM (520 positive with 61 equivocal) overall, in both HNPC and CRPC patients. 18F-DCFBC PET detection of lymph nodes, bone lesions, and visceral lesions was superior to CIM. When intrapatient clustering effects were considered, 18F-DCFBC PET was estimated to be positive in a large proportion of lesions that would be negative or equivocal on CIM (0.45). On follow-up, the sensitivity of 18F-DCFBC PET (0.92) was superior to CIM (0.71). 18F-DCFBC tumor uptake was increased at the later PET time point (∼2.5 h after injection), with background uptake showing a decreasing trend on later PET. Conclusion: PET imaging with 18F-DCFBC, a small-molecule PSMA-targeted radiotracer, detected more lesions than CIM and promises to diagnose and stage patients with metastatic prostate cancer more accurately than current imaging methods.

PET imaging of prostate-specific membrane antigen in prostate cancer: current state of the art and future challenges

Background:Prostate-specific membrane antigen (PSMA) is a cell surface enzyme that is highly expressed in prostate cancer (PCa) and is currently being extensively explored as a promising target for molecular imaging in a variety of clinical contexts. Novel antibody and small-molecule PSMA radiotracers labeled with a variety of radionuclides for positron emission tomography (PET) imaging applications have been developed and explored in recent studies.Methods:A great deal of progress has been made in defining the clinical utility of this class of PET agents through predominantly small and retrospective clinical studies. The most compelling data to date has been in the setting of biochemically recurrent PCa, where PSMA-targeted radiotracers have been found to be superior to conventional imaging and other molecular imaging agents for the detection of locally recurrent and metastatic PCa.Results:Early data, however, suggest that initial lymph node staging before definitive therapy in high-risk primary PCa patients may be limited, although intraoperative guidance may still hold promise. Other examples of potential promising applications for PSMA PET imaging include non-invasive characterization of primary PCa, staging and treatment planning for PSMA-targeted radiotherapeutics, and guidance of focal therapy for oligometastatic disease.Conclusions:However, all of these indications and applications for PCa PSMA PET imaging are still lacking and require large, prospective, systematic clinical trials for validation. Such validation trials are needed and hopefully will be forthcoming as the fields of molecular imaging, urology, radiation oncology and medical oncology continue to define and refine the utility of PSMA-targeted PET imaging to improve the management of PCa patients.