Testosterone Responders to Continuous Androgen Deprivation Therapy Show Considerable Variations in Testosterone Levels on Followup: Implications for Clinical Practice.

PURPOSE: We determined whether men on continuous androgen deprivation therapy who achieve testosterone less than 0.7 nmol/l demonstrate subsequent testosterone elevations during followup and whether such events predict worse oncologic outcomes. MATERIALS AND METHODS: We evaluated a random, retrospective sample of 514 patients with prostate cancer treated with continuous androgen deprivation therapy in whom serum testosterone was less than 0.7 nmol/l at University Health Network between 2007 and 2016. Patients were followed from the date of the first testosterone measurement of less than 0.7 nmol/l to progression to castrate resistance, death or study period end. Study outcomes were the development of testosterone elevations greater than 0.7, greater than 1.1 and greater than 1.7 nmol/l, and progression to a castrate resistant state. Survival curves were constructed to determine the rate of testosterone elevations. Multivariate Cox regression analysis was done to assess whether elevations predicted progression to castrate resistance. RESULTS: Median patient age was 74 years and median followup was 20.3 months. Within 5 years of followup 82%, 45% and 18% of patients had subsequent testosterone levels greater than 0.7, greater than 1.1 and greater than 1.7 nmol/l, respectively. In 96% to 100% of these patients levels less than 0.7 nmol/l were subsequently reestablished within 5 years. No patient baseline characteristic was associated with elevations and elevations were not a significant predictor of progression to a castrate resistant state. CONCLUSIONS: Men on continuous androgen deprivation therapy in whom initial testosterone is less than 0.7 nmol/l frequently show subsequent elevations in serum testosterone. Such a development should not trigger an immediate response from physicians as these events are prognostically insignificant with regard to oncologic outcomes. Levels are eventually reestablished at less than 0.7 nmol/l.

What false-negative rates of non-invasive testing are active surveillance patients and uro-oncologists willing to accept in order to avoid prostate biopsy?

INTRODUCTION: Repeat prostate biopsies in active surveillance patients are associated with significant complications. Novel imaging and blood/urine-based non-invasive tests are being developed to better predict disease grade and volume progression. We conducted a theoretical study to determine what test performance characteristics and costs would a non-invasive test(s) require in order for patients and their physicians to comfortably avoid biopsy. METHODS: Surveys were administered to two populations to determine an acceptable false-negative rate and cost for such test(s). Active surveillance patients were recruited at time of followup in clinic at Princess Margaret Cancer Centre. Physician members of the Society of Urological Oncology were targeted via an online survey. Participants were questioned about their demographics and other characteristics that might influence chosen error rates and cost. RESULTS: 136 patients and 670 physicians were surveyed, with 130 (95.6%) and 104 (15.5%) responses obtained, respectively. A vast majority of patients (90.6%) were comfortable with a non-invasive test(s) in place of biopsy, with 64.8% accepting a false-negative rate of 5-20%. Most physicians (93.3%) were comfortable with a non-invasive test, with 77.9% accepting a rate of 5-20%. Most patients and physicians felt that a cost of less than $1000 per administration would be reasonable. CONCLUSIONS: Most patients/physicians are comfortable with a non-invasive test(s). Although a 5% error rate seems acceptable to many, a substantial subset feels that 99% or higher negative predictive value is required. Thus, a personalized approach with shared decision-making between patients and physicians is essential to optimize patient care in such situations.

Germline Mutations in the Kallikrein 6 Region and Predisposition for Aggressive Prostate Cancer.

Background: There is a need for markers that can specifically identify individuals at increased risk of harboring aggressive forms of prostate cancer (PCa). Methods: We surveyed the Kallikrein ( KLK ) region ( KLK 1-15) for single-nucleotide polymorphisms (SNPs) associated with aggressive PCa (Gleason Score ≥ 8) in 1858 PCa patients. Discovery cohorts (Swiss arm of the European Randomized Study of Screening for PCa, n = 379; Toronto, Canada, n = 540) and a validation cohort (Prostate, Lung, Colorectal and Ovarian [PLCO] screening trial, n = 939) were analyzed. Fine-mapping within the KLK region was carried out by genotyping and imputation in the discovery cohort, whereas PLCO data were provided through database of Genotypes and Phenotypes ( dbGaP ). The influence of SNPs of interest on biochemical-free survival was evaluated in a cohort of localized PCa from the International Cancer Genome Consortium (ICGC; n = 130) analyzed with next-generation sequencing. Single- and multi-SNP association studies, as well as haplotype analyses, were performed. All statistical tests were two-sided. Results: Several SNPs in very strong linkage disequilibrium in the KLK 6 region and located within the same haplotype (rs113640578, rs79324425, rs11666929, rs28384475, rs3810287), identified individuals at increased risk of aggressive PCa in both discovery (odds ratio [OR] = 3.51-3.64, 95% confidence interval [CI] = 2.01 to 6.36, P = 1.0x10 -5 -8.4x10 -6 ) and validation (OR = 1.89-1.96, 95% CI = 0.99 to 3.71, P = .04-.05) cohorts. The overall test of haplotype association was highly statistically significant in each cohort ( P = 3.5x10 -4 and .006, respectively) and in the three data sets combined ( P = 2.3x10 -5 ). These germline SNPs independently predicted relapse in the ICGC cohort (hazard ratio = 3.15, 95% CI = 1.57 to 6.34, P = .001). Conclusions: Our fine-mapping study has identified novel loci in the KLK 6 region strongly associated with aggressive PCa.

The association of male pattern baldness and risk of cancer and high-grade disease among men presenting for prostate biopsy.

INTRODUCTION: Androgens have been implicated in both male pattern baldness (MPB) and prostate cancer (PCa). We set out to prospectively determine if men with independently assessed MPB are at higher risk for PCa at biopsy and determine if any grade associations exist. METHODS: We prospectively enrolled 394 eligible patients presenting for prostate biopsy and independently determined their MPB pattern using the validated modified Norwood classification system (0: no balding; 1: frontal balding; 2: mild vertex balding; 3: moderate vertex balding; 4: sever vertex balding). Univariate and multivariable models, including Norwood score, age, prostate-specific antigen, and digital rectal examination abnormalities, were calculated for the outcomes of cancer and high-grade disease (Gleason >6). C-statistics analyses of our models were then compared with and without MPB pattern for marginal utility. RESULTS: Norwood patterns were increasingly associated with cancer and high-grade disease with a dose-effect (p for trend <0.001 on univariate and multivariable analyses for cancer and p=0.001 and p=0.0036 for high-grade disease on univariate and multivariable analyses, respectively). On multivariable analyses, trends still held, with all patients exhibiting Norwood scale 3 and 4 at increased risk for cancer. In predicting risk of high-grade disease, only patients with Norwood pattern 4 exhibited an increased risk. CONCLUSIONS: MPB appears to be a strong and independent risk factor for both cancer and high-grade disease for men presenting for prostate biopsy. Ours could be superior to marketed costly genetic tests. Further research is needed to understand the biology behind this observation and to incorporate these findings into clinical decision-making.

Impact of prostate-specific antigen on a baseline prostate cancer risk assessment including genetic risk.

OBJECTIVE: To determine to what extent prostate cancer (PCa) risk prediction is improved by adding prostate-specific antigen (PSA) to a baseline model including genetic risk. METHODS: Peripheral blood deoxyribonucleic acid was obtained from Caucasian men undergoing prostate biopsy at the University of Toronto (September 1, 2008 to January 31, 2010). Thirty-three PCa risk-associated single nucleotide polymorphisms were genotyped to generate the prostate cancer genetic score 33 (PGS-33). Primary outcome is PCa on study prostate biopsy. Logistic regression, area under the receiver-operating characteristic curves (AUC), and net reclassification improvement were used to compare models. RESULTS: Among 670 patients, 323 (48.2%) were diagnosed with PCa. The PGS-33 was highly associated with biopsy-detectable PCa (odds ratio, 1.66; P = 5.86E-05; AUC, 0.59) compared with PSA (odds ratio, 1.33; P = .01; AUC, 0.55). PSA did not improve risk prediction when added to a baseline model (age, family history, digital rectal examination, and PGS-33) for overall risk (AUC, 0.66 vs 0.66; P = .86) or Gleason score ≥7 PCa (AUC, 0.71 vs 0.73; P = .15). Net reclassification improvement analyses demonstrated no appropriate reclassifications with the addition of PSA to the baseline model for overall PCa but did show some benefit for reclassification of men thought to be at higher baseline risk in the high-grade PCa analysis. CONCLUSION: In a baseline model of PCa risk including the PGS-33, PSA does not add to risk prediction for overall PCa for men presenting for "for-cause" biopsy. These findings suggest that PSA screening may be minimized in men at low baseline risk.

Cholesterol masks membrane glycosphingolipid tumor-associated antigens to reduce their immunodetection in human cancer biopsies.

Glycosphingolipids (GSLs) are neoplastic and normal/cancer stem cell markers and GSL/cholesterol-containing membrane rafts are increased in cancer cell plasma membranes. We define a novel means by which cancer cells can restrict tumor-associated GSL immunoreactivity. The GSL-cholesterol complex reorients GSL carbohydrate to a membrane parallel, rather than perpendicular conformation, largely unavailable for antibody recognition. Methyl-ß-cyclodextrin cholesterol extraction of all primary human tumor frozen sections tested (ovarian, testicular, neuroblastoma, prostate, breast, colon, pheochromocytoma and ganglioneuroma), unmasked previously "invisible" membrane GSLs for immunodetection. In ovarian carcinoma, globotriaosyl ceramide (Gb3), the GSL receptor for the antineoplastic Escherichia coli-derived verotoxin, was increased throughout the tumor. In colon carcinoma, Gb3 detection was vastly increased within the neovasculature and perivascular stroma. In tumors considered Gb3 negative (neuroblastoma, Leydig testicular tumor and pheochromocytoma), neovascular Gb3 was unmasked. Tumor-associated GSL stage-specific embryonic antigen (SSEA)-1, SSEA-3, SSEA-4 and globoH were unmasked according to tumor: SSEA-1 in prostate/colon; SSEA-3 in prostate; SSEA-4 in pheochromocytoma/some colon tumors; globoH in prostate/some colon tumors. In colon, anti-SSEA-1 was tumor cell specific. Within the GSL-cholesterol complex, filipin-cholesterol binding was also reduced. These results may relate to the ill-defined benefit of statins on cancer prognosis, for example, prostate carcinoma. We found novel anti-tumor GSL antibodies circulating in 3/5 statin-treated, but not untreated, prostate cancer patients. Lowering tumor membrane cholesterol may permit immune recognition of otherwise unavailable tumor-associated GSL carbohydrate, for more effective immunosurveillance and active/passive immunotherapy. Our results show standard immunodetection of tumor GSLs significantly under assesses tumor membrane GSL content, impinging on the current use of such antigens as cancer vaccines.

Comparison of risk calculators from the Prostate Cancer Prevention Trial and the European Randomized Study of Screening for Prostate Cancer in a contemporary Canadian cohort.

OBJECTIVE: •To compare the Prostate Cancer Prevention Trial Risk Calculator (PCPT-RC) and European Randomized Study of Screening for Prostate Cancer Risk Calculator (ERSPC-RC) in a single-institution Canadian cohort. PATIENTS AND METHODS: •At Princess Margaret Hospital, 982 consecutive patients with PCPT-RC and ERSPC-RC covariables were prospectively catalogued before prostate biopsy for suspicion of prostate cancer (PCa). •Receiver-operating characteristic (ROC) curves were generated for each calculator and prostate-specific antigen (PSA). •Comparisons by area under the curve (AUC) and calibration plots were performed. •Predictors of PCa were identified by univariable and multivariable logistic regression. RESULTS: •PCa was detected in 46% and high-grade (HG) PCa (Gleason ≥4) in 23% of subjects with a median PSA level of 6.02 ng/mL. • Multivariable analysis identified transrectal ultrasonography nodule, prostate volume and PSA as the most important predictors of PCa and HG PCa. •ROC curve analysis showed that the ERSPC-RC (AUC = 0.71) outperformed the PCPT-RC (AUC = 0.63) and PSA (AUC = 0.55), for PCa prediction, P < 0.001. •The PCPT-RC was better calibrated in the higher prediction range (40-100%) than the ERSPC-RC, whereas the ERSPC-RC had better calibration and avoided more biopsies in the lower risk range (0-30%). •Discrimination of the ERSPC-RC continued to be superior to the PCPT-RC when the cohort was stratified by different clinical variables. CONCLUSIONS: •The ERSPC-RC had better discrimination for predicting PCa compared to the PCPT-RC in this Canadian cohort. •Calibration would need to be improved to allow routine use of the ERSPC-RC in Canadian practice.

Clinical significance of the positive surgical margin based upon location, grade, and stage.

Prostate cancer remains a challenge due to its incidence and radical prostatectomy continues to be a major treatment option for men with potentially curable disease who have a life expectancy over a decade. This article will address the common problem of positive surgical margins and the impact of them on patient outcome. Through these we can examine relevant clinical trials that have attempted to address this issue and offer some guided to therapy among men with this clinical problem. Close margins are probably of no significance and will not be addressed. Our recommendations take into account the current level of medical evidence, and are balanced with anticipated adverse effects of treatment. They may change over time once definitive clinical trials are completed. In brief we believe those with positive margins and PT2 we advocate close observation with the aim of early salvage radiotherapy if necessary. Those with PT3a and focally positive margins with low/intermediate grade tumors are at moderate risk of biochemical failure so should be managed like PT2 patients. However those with high-grade disease should be offered adjuvant radiotherapy. Similarly those with PT3a margin positive extensive or multiple site disease should have adjuvant radiotherapy. PT3B margin positive patients should be offered radiotherapy. PT4 with bladder neck only margin positive can probably be observed.