PI-RADS Version 2.0 Versus Version 2.1: Comparison of Prostate Cancer Gleason Grade Upgrade and Downgrade Rates From MRI-Targeted Biopsy to Radical Prostatectomy

BACKGROUND. Precise risk stratification through MRI/ultrasound (US) fusion-guided targeted biopsy (TBx) can guide optimal prostate cancer (PCa) management. OBJECTIVE. The purpose of this study was to compare PI-RADS version 2.0 (v2.0) and PI-RADS version 2.1 (v2.1) in terms of the rates of International Society of Urological Pathology (ISUP) grade group (GG) upgrade and downgrade from TBx to radical prostatectomy (RP). METHODS. This study entailed a retrospective post hoc analysis of patients who underwent 3-T prostate MRI at a single institution from May 2015 to March 2023 as part of three prospective clinical trials. Trial participants who underwent MRI followed by MRI/US fusion-guided TBx and RP within a 1-year interval were identified. A single genitourinary radiologist performed clinical interpretations of the MRI examinations using PI-RADS v2.0 from May 2015 to March 2019 and PI-RADS v2.1 from April 2019 to March 2023. Upgrade and downgrade rates from TBx to RP were compared using chi-square tests. Clinically significant cancer was defined as ISUP GG2 or greater. RESULTS. The final analysis included 308 patients (median age, 65 years; median PSA density, 0.16 ng/mL2). The v2.0 group (n = 177) and v2.1 group (n = 131) showed no significant difference in terms of upgrade rate (29% vs 22%, respectively; p = .15), downgrade rate (19% vs 21%, p = .76), clinically significant upgrade rate (14% vs 10%, p = .27), or clinically significant downgrade rate (1% vs 1%, p > .99). The upgrade rate and downgrade rate were also not significantly different between the v2.0 and v2.1 groups when stratifying by index lesion PI-RADS category or index lesion zone, as well as when assessed only in patients without a prior PCa diagnosis (all p > .01). Among patients with GG2 or GG3 at RP (n = 121 for v2.0; n = 103 for v2.1), the concordance rate between TBx and RP was not significantly different between the v2.0 and v2.1 groups (53% vs 57%, p = .51). CONCLUSION. Upgrade and downgrade rates from TBx to RP were not significantly different between patients whose MRI examinations were clinically interpreted using v2.0 or v2.1. CLINICAL IMPACT. Implementation of the most recent PI-RADS update did not improve the incongruence in PCa grade assessment between TBx and surgery.

Comparison of MRI-Based Staging and Pathologic Staging for Predicting Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy

BACKGROUND. Currently most clinical models for predicting biochemical recurrence (BCR) of prostate cancer (PCa) after radical prostatectomy (RP) incorporate staging information from RP specimens, creating a gap in preoperative risk assessment. OBJECTIVE. The purpose of our study was to compare the utility of presurgical staging information from MRI and postsurgical staging information from RP pathology in predicting BCR in patients with PCa. METHODS. This retrospective study included 604 patients (median age, 60 years) with PCa who underwent prostate MRI before RP from June 2007 to December 2018. A single genitourinary radiologist assessed MRI examinations for extraprostatic extension (EPE) and seminal vesicle invasion (SVI) during clinical interpretations. The utility of EPE and SVI on MRI and RP pathology for BCR prediction was assessed through Kaplan-Meier and Cox proportional hazards analyses. Established clinical BCR prediction models, including the University of California San Francisco Cancer of the Prostate Risk Assessment (UCSF-CAPRA) model and the Cancer of the Prostate Risk Assessment Postsurgical (CAPRA-S) model, were evaluated in a subset of 374 patients with available Gleason grade groups from biopsy and RP pathology; two CAPRA-MRI models (CAPRA-S model with modifications to replace RP pathologic staging features with MRI staging features) were also assessed. RESULTS. Univariable predictors of BCR included EPE on MRI (HR = 3.6), SVI on MRI (HR = 4.4), EPE on RP pathology (HR = 5.0), and SVI on RP pathology (HR = 4.6) (all p < .001). Three-year BCR-free survival (RFS) rates for patients without versus with EPE were 84% versus 59% for MRI and 89% versus 58% for RP pathology, and 3-year RFS rates for patients without versus with SVI were 82% versus 50% for MRI and 83% versus 54% for RP histology (all p < .001). For patients with T3 disease on RP pathology, 3-year RFS rates were 67% and 41% for patients without and with T3 disease on MRI. AUCs of CAPRA models, including CAPRA-MRI models, ranged from 0.743 to 0.778. AUCs were not significantly different between CAPRA-S and CAPRA-MRI models (p > .05). RFS rates were significantly different between low- and intermediate-risk groups for only CAPRA-MRI models (80% vs 51% and 74% vs 44%; both p < .001). CONCLUSION. Presurgical MRI-based staging features perform comparably to postsurgical pathologic staging features for predicting BCR. CLINICAL IMPACT. MRI staging can preoperatively identify patients at high BCR risk, helping to inform early clinical decision-making. TRIAL REGISTRATION. ClinicalTrials.gov NCT00026884 and NCT02594202.

A Phase 2, Double-blind, Randomized Controlled Trial of PROSTVAC in Prostate Cancer Patients on Active Surveillance

BACKGROUND

There is an unmet clinical need for interventions to prevent disease progression in patients with localized prostate cancer on active surveillance (AS).

OBJECTIVE

To determine the immunologic response to the PROSTVAC vaccine and the clinical indicators of disease progression in patients with localized prostate cancer on AS.

DESIGN, SETTING, AND PARTICIPANTS

This was a phase 2, double-blind, randomized controlled trial in 154 men with low- or intermediate-risk prostate cancer on AS.

INTERVENTION

Participants were randomized (2:1) to receive seven doses of subcutaneous PROSTVAC, a vaccinia/fowlpox viral vector-based immunotherapy containing a prostate-specific antigen (PSA) transgene and three T-cell co-stimulatory molecules, or an empty fowlpox vector (EV) over 140 d.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the change from baseline in CD4 and CD8 T-cell infiltration in biopsy tumor tissue. Key secondary outcomes were safety and changes in prostate biopsy tumor pathology, peripheral antigen-specific T cells, and serum PSA. Continuous variables were compared using nonparametric tests. Categorical variables were compared using Fisher's exact test.

RESULTS AND LIMITATIONS

The PROSTVAC/EV vaccination was well tolerated. All except one participant completed the vaccination series. Changes in CD4 or CD8 density in biopsy tumor tissue did not differ between the PROSTVAC and EV arms. The proportions of patients with Gleason upgrading to grade group 3 after treatment was similar between the arms. There were no differences in postvaccination peripheral T-cell responses or the PSA change from baseline to 6-mo post-treatment follow-up between the groups.

CONCLUSIONS

In this first-of-kind trial of immunotherapy in patients on AS for prostate cancer, PROSTVAC did not elicit more favorable prostate tissue or peripheral T-cell responses than the EV. There was no difference between the arms in clinicopathologic effects. Despite the null findings, this is the first study reporting the feasibility and acceptability of an immunotherapy intervention in the AS setting.

PATIENT SUMMARY

We looked at responses after an experimental prostate cancer vaccine in patients with prostate cancer on active surveillance (AS). Participants who received the vaccine did not show more favorable outcomes than those receiving the control. Despite these findings, this is the first report showing the feasibility and acceptability of immunotherapy for prostate cancer in patients on AS.

Cabozantinib plus Nivolumab Phase I Expansion Study in Patients with Metastatic Urothelial Carcinoma Refractory to Immune Checkpoint Inhibitor Therapy

PURPOSE

This study investigated the efficacy and tolerability of cabozantinib plus nivolumab (CaboNivo) in patients with metastatic urothelial carcinoma (mUC) that progressed on checkpoint inhibition (CPI).

PATIENTS AND METHODS

A phase I expansion cohort of patients with mUC who received prior CPI was treated with cabozantinib 40 mg/day and nivolumab 3 mg/kg every 2 weeks until disease progression/unacceptable toxicity. The primary goal was objective response rate (ORR) per RECIST v.1.1. Secondary objectives included progression-free survival (PFS), duration of response (DoR), overall survival (OS), safety, and tolerability.

RESULTS

Twenty-nine out of 30 patients enrolled were evaluable for efficacy. Median follow-up was 22.2 months. Most patients (86.7%) received prior chemotherapy and all patients received prior CPI (median seven cycles). ORR was 16.0%, with one complete response and three partial responses (PR). Among 4 responders, 2 were primary refractory, 1 had a PR, and 1 had stable disease on prior CPI. Median DoR was 33.5 months [95% confidence interval (CI), 3.7-33.5], median PFS was 3.6 months (95% CI, 2.1-5.5), and median OS was 10.4 months (95% CI, 5.8-19.5). CaboNivo decreased immunosuppressive subsets such as regulatory T cells (Tregs) and increased potential antitumor immune subsets such as nonclassical monocytes and effector T cells. A lower percentage of monocytic myeloid-derived suppressor cells (M-MDSC) and polymorphonuclear MDSCs, lower CTLA-4 and TIM-3 expression on Tregs, and higher effector CD4+ T cells at baseline were associated with better PFS and/or OS.

CONCLUSIONS

CaboNivo was clinically active, well tolerated, and favorably modulated peripheral blood immune subsets in patients with mUC refractory to CPI.

Immunotherapy to prevent progression on active surveillance study (IPASS): A phase II, randomized, double-blind, controlled trial of PROSTVAC in prostate cancer patients who are candidates for active surveillance

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Background: Immunotherapy could potentially prevent disease progression for early-stage prostate cancer. In this randomized Phase 2 clinical trial, we evaluated the clinical effects of PROSTVAC, a vaccinia/fowlpox viral vector-based immunotherapy that contains PSA and three T-cell costimulatory molecules, in patients with localized prostate cancer. Methods:154 patients with clinically localized, low- or favorable intermediate-risk prostate cancer active surveillance were randomized (2:1) to receive 7 doses of subcutaneous PROSTVAC or placebo (empty fowlpox vector) over 140 days. Post-intervention prostate biopsy was performed 7-14 days after the last dose. Participants were followed for 6 months post-treatment. The primary outcome was change from baseline to post-vaccination in CD4 and CD8 T cell infiltration in biopsy tumor tissue. Secondary outcomes included changes in prostate biopsy Gleason grade (Grade Group) and serum PSA. Results: There were no differences in CD4 and CD8 densities (count of cells/mm2) in post-treatment biopsy tumor tissue between groups ( p = 0.63 and p = 0.75, respectively). Compared to placebo, patients who received PROSTVAC were less likely to demonstrate upgrading at follow-up biopsy, but this difference did not attain significance (22% vs. 40%, p= 0.08). There was no difference in the change of PSA from baseline to 6 months post-treatment between arms ( p= 0.30). Conclusions: In this first-of-kind trial of immunotherapy for localized prostate cancer, PROSTVAC was well tolerated but did not elicit significant prostate tissue T-cell responses compared to placebo. The favorable post-treatment biopsy grade findings in PROSTVAC patients merit further evaluation and longer-term clinical follow-up. Clinical trial information: NCT02326805.

Association of Serum Carotenoids and Retinoids with Intraprostatic Inflammation in Men without Prostate Cancer or Clinical Indication for Biopsy in the Placebo Arm of the Prostate Cancer Prevention Trial

Non-supplemental carotenoids and retinol may potentiate antioxidant and anti-inflammatory mechanisms. Chronic intraprostatic inflammation is linked to prostate carcinogenesis. We investigated the association of circulating carotenoids and retinol with intraprostatic inflammation in benign tissue. We included 235 men from the Prostate Cancer Prevention Trial placebo arm who had a negative end-of-study biopsy, most (92.8%) done without clinical indication. α-carotene, β-carotene, β-cryptoxanthin, lycopene, and retinol were assessed by high-performance liquid chromatography using pooled year 1 and 4 serum. Presence and extent of intraprostatic inflammation in benign tissue was assessed in 3 (of 6-10) biopsy cores. Logistic (any core with inflammation vs none) and polytomous logistic (some or all cores with inflammation vs none) regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) of intraprostatic inflammation by concentration tertile adjusting for age, race, prostate cancer family history, and serum cholesterol. None of the carotenoids or retinol was associated with intraprostatic inflammation, except β-cryptoxanthin, which appeared to be positively associated with any core with inflammation [vs none, T2: OR (95% CI) = 2.67 (1.19, 5.99); T3: 1.80 (0.84, 3.82), P-trend = 0.12]. These findings suggest that common circulating carotenoids and retinol are not useful dietary intervention targets for preventing prostate cancer via modulating intraprostatic inflammation.

A Polygenic Risk Score Predicts Incident Prostate Cancer Risk in Older Men but Does Not Select for Clinically Significant Disease

Despite the high prevalence of prostate cancer in older men, the predictive value of a polygenic risk score (PRS) remains uncertain in men aged ≥70 years. We used a 6.6 million-variant PRS to predict the risk of incident prostate cancer in a prospective study of 5701 men of European descent aged ≥70 years (mean age 75 years) enrolled in the ASPirin in Reducing Events in the Elderly (ASPREE) clinical trial. The study endpoint was prostate cancer, including metastatic or non-metastatic disease, confirmed by an expert panel. After excluding participants with a history of prostate cancer at enrolment, we used a multivariable Cox proportional hazards model to assess the association between the PRS and incident prostate cancer risk, adjusting for covariates. Additionally, we examined the distribution of Gleason grade groups by PRS group to determine if a higher PRS was associated with higher grade disease. We tested for interaction between the PRS and aspirin treatment. Logistic regression was used to independently assess the association of the PRS with prevalent (pre-trial) prostate cancer, reported in medical histories. During a median follow-up time of 4.6 years, 218 of the 5701 participants (3.8%) were diagnosed with prostate cancer. The PRS predicted incident risk with a hazard ratio (HR) of 1.52 per standard deviation (SD) (95% confidence interval (CI) 1.33-1.74, p < 0.001). Men in the top quintile of the PRS distribution had an almost three times higher risk of prostate cancer than men in the lowest quintile (HR = 2.99 (95% CI 1.90-4.27), p < 0.001). However, a higher PRS was not associated with a higher Gleason grade groups. We found no interaction between aspirin treatment and the PRS for prostate cancer risk. The PRS was also associated with prevalent prostate cancer (odds ratio = 1.80 per SD (95% CI 1.65-1.96), p < 0.001).While a PRS for prostate cancer is strongly associated with incident risk in men aged ≥70 years, the clinical utility of the PRS as a biomarker is currently limited by its inability to select for clinically significant disease.

Risk of adverse pathology at prostatectomy in the era of MRI and targeted biopsies; rethinking active surveillance for intermediate risk prostate cancer patients

PURPOSE

Men with intermediate risk (IR) prostate cancer (CaP) are often excluded from active surveillance (AS) due to higher rates of adverse pathology (AP). We determined our rate of AP in men who underwent multiparametric MRI (MpMRI) with combined biopsy (CB) consisting of targeted biopsy (TB) and systematic biopsy (SB) prior to radical prostatectomy (RP).

METHODS

A retrospective review was conducted of men with Gleason Grade Group (GG) 2 disease who underwent RP after SB alone or after preoperative MRI with CB. AP was defined as either pathologic stage T3a (AP ≥ T3a) or pathologic stage T3b (AP ≥ T3b) and/or GG upgrading. Rates of AP were determined for both groups and those who fit the National Comprehensive Cancer Network (NCCN) definition of favorable IR (FIR) or the low volume IR (LVIR) criteria. Multivariable logistic regression was used to determine predictive factors.

RESULTS

The overall rate of AP ≥ T3b was 21.2% in the SB group vs. 8.6% in the MRI with CB group, P = 0.006. This rate was lowered to 6.8% and 5.6% when men met the definition of NCCN FIR or LVIR, respectively. Suspicion for extraprostatic extension (EPE) (OR 7.65, 95% CI 1.77-33.09, P = 0.006) and positive cores of GG 2 on SB (OR 1.43, 95% CI 1.05-1.96, P = 0.023) were significant for predicting AP ≥ T3b.

CONCLUSIONS

Rates of AP at RP after MRI with CB are lower than studies prior to the adoption of this technology, suggesting that more men with IR disease may be considered for AS. However, increasing cores positive on SB and MRI findings suggestive of EPE remain unsafe.

Final results from a phase I trial and expansion cohorts of cabozantinib and nivolumab (CaboNivo) alone or with ipilimumab (CaboNivoIpi) for metastatic genitourinary tumors

3

Background: CaboNivo and CaboNivoIpi showed promising efficacy and safety in a dose-escalation phase I study in patients (pts) with metastatic genitourinary (mGU) tumors. We now report the final results from a pooled analysis of the phase I dose-finding and 7 subsequent expansion cohorts. Methods: Pts with mGU tumors in the phase I cohort received 8 escalating doses of CaboNivo or CaboNivoIpi. In the 7 expansion cohorts, pts received the recommended phase II dose for CaboNivo (cabo 40mg qd + nivo 3mg/kg q2wks in 28-day cycles) and for CaboNivoIpi (CaboNivo same dose + ipi 1mg/kg q3wks in 21-day cycles x 4 cycles followed by CaboNivo). The CaboNivo expansion cohorts included pts with urothelial carcinoma (UC); clear cell renal cell carcinoma (RCC), bladder adenocarcinoma (BlaAdeno), and other rare mGU tumors. The CaboNivoIpi expansion cohorts included, UC, RCC, and penile carcinoma (penile). The objectives of the study were to determine the clinical activity, safety and tolerability of both combinations. A secondary objective was the detection of EpCAM+ circulating tumor cells (CTCs). Biomarker correlatives of plasma VEGFA/VEGFR2, PIGF, and inflammatory cytokines will be presented. Results: A total of 120 pts (median age 59; range 20-82) were enrolled: 54 in the phase I and 66 in the dose expansion cohorts. 64 pts received CaboNivo and 56 CaboNivoIpi. Median follow-up was 40.4 months (range 2.2-62.2 months). The ORR for 108 evaluable pts was 38% (95% CI: 28.8-47.8%) with 12 complete responses (CRs) (11.1%) and 29 partial responses (26.9%). The ORRs for the following mGU tumors were: UC 42.4% (n=33) with CR=21.2%; RCC 62.5% (n=16); prostate cancer 11.1% (n=9); germ cell tumor no responses (n=6); BlaAdeno 20% (n=15); penile 44.4% (n=9); bladder squamous 85.7 (n=7); renal medullary 50% (n=2); bladder small cell 33.1 (n=3). The median overall survival for the entire population was 15.9 months (95% CI: 11.6-23.9); 24.9 months (95% CI: 11.8-41.6) for pts with UC (n=39); and 38.6 months (95% CI: 19.4-not estimable) for RCC (n=16). Median duration of response was 22.8 months (95% CI: 18.3-40.1 months) for all pts, 32.1 months [95% CI: 20.3-NE)] for the UC pts and 20.1 months (95% CI: 5.8-NE) for RCC pts. Grade 3 or 4 treatment related adverse events (AEs) occurred in 84% and 80% of pts treated with CaboNivo and CaboNivoIpi pts respectively, and included hypophosphatemia (25% and 16%), lipase elevation (20% and 20%), fatigue (20% and 18%), ALT elevation (5% and 14%), AST elevation (9% and 11%), diarrhea (9% and 11%), and thromboembolic event (11% and 4%). One pt had Grade 5 pneumonitis on CaboNivoIpi. Baseline EpCAM+ CTC count of < 5 vs. > 5, was associated with longer median OS (24.3 vs. 12.3 months p=0.037). Conclusions: CaboNivo and CaboNivoIpi demonstrated promising clinical activity and manageable safety in many mGU histologies including rare tumors. Clinical trial information: NCT02496208.

A phase II randomized placebo-controlled trial of pomegranate fruit extract in men with localized prostate cancer undergoing active surveillance

INTRODUCTION OR OBJECTIVE

Men with favorable-risk prostate cancer (PCa) on active surveillance may benefit from intervention strategies to slow or prevent disease progression and the need for definitive treatment. Pomegranate and its extracts have shown antiproliferative and proapoptotic effects in cell lines and animal models, but its effect on human prostate cancer as a target tissue remain unclear. Objectives of this trial include pomegranate's ability to alter serum and prostate tissue biomarkers and the ability of an active surveillance cohort to adhere to a chemoprevention trial for 1 year.

METHODS

Men with organ-confined, favorable-risk PCa on AS were randomly assigned to receive pomegranate fruit extract (PFE) 1000 mg (n = 15) or placebo (n = 15) once daily for twelve months. Prostate biopsies were performed at study entry and upon completion of the 1-year intervention. Plasma and urinary biomarkers were analyzed utilizing immunoassays and HPLC. Tissue proteins were assessed by immunohistochemistry (IHC) and measured by automated quantitation.

RESULTS

PFE was well-tolerated with no significant toxicities. One patient withdrew before study initiation and 29 completed the 1-year intervention. No differences in plasma insulin-like growth factor-1 (IGF-1) levels, prostate-specific antigen doubling time, or biopsy kinetics were observed. Metabolites including urolithin A and urolithin A-gluc were detected more frequently in the PFE arm in both urine and plasma (p < .001 and p = .006, respectively). IHC analyses revealed reductions from baseline in 8-OHdG (a DNA damage marker) (p = .01) and androgen receptor expression (p = .04) in prostate tumor associated with PFE treatment.

CONCLUSION

PFE administration for 12-month was well-tolerated and the protocol followed in an active surveillance population. Analyses suggest that PFE contains bioactive compounds capable of altering biomarkers involving oxidative stress and androgen signaling in prostate tumor and normal-appearing adjacent tissue. No alterations in the IGF axis were noted. This finding of study adherence and target activity provides a rationale for the further investigation of PFE in the active surveillance population.

Phase I Study of Cabozantinib and Nivolumab Alone or With Ipilimumab for Advanced or Metastatic Urothelial Carcinoma and Other Genitourinary Tumors

PURPOSE

We assessed the safety and efficacy of cabozantinib and nivolumab (CaboNivo) and CaboNivo plus ipilimumab (CaboNivoIpi) in patients with metastatic urothelial carcinoma (mUC) and other genitourinary (GU) malignances.

PATIENTS AND METHODS

Patients received escalating doses of CaboNivo or CaboNivoIpi. The primary objective was to establish a recommended phase II dose (RP2D). Secondary objectives included objective response rate (ORR), progression-free survival (PFS), duration of response (DoR), and overall survival (OS).

RESULTS

Fifty-four patients were enrolled at eight dose levels with a median follow-up time of 44.6 months; data cutoff was January 20, 2020. Grade 3 or 4 treatment-related adverse events (AEs) occurred in 75% and 87% of patients treated with CaboNivo and CaboNivoIpi, respectively, and included fatigue (17% and 10%, respectively), diarrhea (4% and 7%, respectively), and hypertension (21% and 10%, respectively); grade 3 or 4 immune-related AEs included hepatitis (0% and 13%, respectively) and colitis (0% and 7%, respectively). The RP2D was cabozantinib 40 mg/d plus nivolumab 3 mg/kg for CaboNivo and cabozantinib 40 mg/d, nivolumab 3 mg/kg, and ipilimumab 1 mg/kg for CaboNivoIpi. ORR was 30.6% (95% CI, 20.0% to 47.5%) for all patients and 38.5% (95% CI, 13.9% to 68.4%) for patients with mUC. Median DoR was 21.0 months (95% CI, 5.4 to 24.1 months) for all patients and not reached for patients with mUC. Median PFS was 5.1 months (95% CI, 3.5 to 6.9 months) for all patients and 12.8 months (95% CI, 1.8 to 24.1 months) for patients with mUC. Median OS was 12.6 months (95% CI, 6.9 to 18.8 months) for all patients and 25.4 months (95% CI, 5.7 to 41.6 months) for patients with mUC.

CONCLUSION

CaboNivo and CaboNivoIpi demonstrated manageable toxicities with durable responses and encouraging survival in patients with mUC and other GU tumors. Multiple phase II and III trials are ongoing for these combinations.

Changes in Magnetic Resonance Imaging Using the Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation Criteria to Detect Prostate Cancer Progression for Men on Active Surveillance

BACKGROUND

The ability of serial magnetic resonance imaging (MRI) to capture pathologic progression during active surveillance (AS) remains in question.

OBJECTIVE

To determine whether changes in MRI are associated with pathologic progression for patients on AS.

DESIGN, SETTING, AND PARTICIPANTS

From July 2007 through January 2020, we identified all patients evaluated for AS at our institution. Following confirmatory biopsy, a total of 391 patients who underwent surveillance MRI and biopsy at least once were identified (median follow-up of 35.6 mo, interquartile range 19.7-60.6).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

All MRI intervals were scored using the "Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation" (PRECISE) criteria, with PRECISE scores =4 considered a positive change in MRI. A generalized estimating equation-based logistic regression analysis was conducted for all intervals with a PRECISE score of <4 to determine the predictors of Gleason grade group (GG) progression despite stable MRI.

RESULTS AND LIMITATIONS

A total of 621 MRI intervals were scored by PRECISE and validated by biopsy. The negative predictive value of stable MRI (PRECISE score <4) was greatest for detecting GG1 to?=?GG3 disease (0.94 [0.91-0.97]). If 2-yr surveillance biopsy were performed exclusively for a positive change in MRI, 3.7% (4/109) of avoided biopsies would have resulted in missed progression from GG1 to?=?GG3 disease. Prostate-specific antigen (PSA) density (odds ratio 1.95 [1.17-3.25], p?=? 0.01) was a risk factor for progression from GG1 to =GG3 disease despite stable MRI.

CONCLUSIONS

In patients with GG1 disease and stable MRI (PRECISE score <4) on surveillance, grade progression to?=?GG3 disease is not common. In patients with grade progression detected on biopsy despite stable MRI, elevated PSA density appeared to be a risk factor for progression to?=?GG3 disease.

PATIENT SUMMARY

For patients with low-risk prostate cancer on active surveillance, the risk of progressing to grade group 3 disease is low with a stable magnetic resonance image (MRI) after 2?yr. Having higher prostate-specific antigen density increases the risk of progression, despite having a stable MRI.

Cabozantinib in patients with platinum-refractory metastatic urothelial carcinoma: an open-label, single-centre, phase 2 trial

BACKGROUND

Cabozantinib is a multikinase inhibitor of MET, VEGFR, AXL, and RET, which also has an effect on the tumour immune microenvironment by decreasing regulatory T cells and myeloid-derived suppressor cells. In this study, we examined the activity of cabozantinib in patients with metastatic platinum-refractory urothelial carcinoma.

METHODS

This study was an open-label, single-arm, three-cohort phase 2 trial done at the National Cancer Institute (Bethesda, MD, USA). Eligible patients were 18 years or older, had histologically confirmed urothelial carcinoma or rare genitourinary tract histologies, Karnofsky performance scale index of 60% or higher, and documented disease progression after at least one previous line of platinum-based chemotherapy (platinum-refractory). Cohort one included patients with metastatic urothelial carcinoma with measurable disease as defined by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Two additional cohorts that enrolled in parallel (patients with bone-only urothelial carcinoma metastases and patients with rare histologies of the genitourinary tract) were exploratory. Patients received cabozantinib 60 mg orally once daily in 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed objective response rate by RECIST in cohort one. Response was assessed in all patients who met the eligibility criteria and who received at least 8 weeks of therapy. All patients who received at least one dose of cabozantinib were included in the safety analysis. This completed study is registered with ClinicalTrials.gov, NCT01688999.

FINDINGS

Between Sept 28, 2012, and Oct, 20, 2015, 68 patients were enrolled on the study (49 in cohort one, six in cohort two, and 13 in cohort three). All patients received at least one dose of cabozantinib. The median follow-up was 61·2 months (IQR 53·8-70·0) for the 57 patients evaluable for response. In the 42 evaluable patients in cohort one, there was one complete response and seven partial responses (objective response rate 19%, 95% CI 9-34). The most common grade 3-4 adverse events were fatigue (six [9%] patients), hypertension (five [7%]), proteinuria (four [6%]), and hypophosphataemia (four [6%]). There were no treatment-related deaths.

INTERPRETATION

Cabozantinib has single-agent clinical activity in patients with heavily pretreated, platinum-refractory metastatic urothelial carcinoma with measurable disease and bone metastases and is generally well tolerated. Cabozantinib has innate and adaptive immunomodulatory properties providing a rationale for combining cabozantinib with immunotherapeutic strategies.

FUNDING

National Cancer Institute Intramural Program and the Cancer Therapy Evaluation Program.

The association between serum sex steroid hormone concentrations and intraprostatic inflammation in men without prostate cancer and irrespective of clinical indication for biopsy in the placebo arm of the Prostate Cancer Prevention Trial

BACKGROUND

Intraprostatic inflammation is an emerging prostate cancer risk factor. Estrogens are pro-inflammatory while androgens are anti-inflammatory. Thus, we investigated whether serum sex steroid hormone concentrations are associated with intraprostatic inflammation to inform mechanistic links among hormones, inflammation, and prostate cancer.

METHODS

We conducted a cross-sectional study among 247 men in the placebo arm of the Prostate Cancer Prevention Trial who had a negative end-of-study biopsy, most (92.7%) performed without clinical indication per trial protocol. Serum estradiol, estrone, and testosterone were previously measured by immunoassay in pooled baseline and Year 3 serum. Free estradiol and free testosterone were calculated. Inflammation was visually assessed (median of three prostate biopsy cores per man). Polytomous or logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (CI) of some or all cores inflamed (both vs none) or any core inflamed (vs none) by hormone tertile, adjusting for age, race, and family history. We evaluated effect modification by waist circumference and body mass index (BMI).

RESULTS

In all, 51.4% had some and 26.3% had all cores inflamed. Free (P-trend = .11) but not total estradiol was suggestively inversely associated with all cores inflamed. In men with waist circumference greater than or equal to 102 cm (P-trend = .021) and BMI ≥ 27.09 kg/m² (P-trend = .0037) free estradiol was inversely associated with any core inflamed. Estrone was inversely associated with all cores inflamed (T3: OR = 0.36, 95% CI 0.14-0.95, P-trend = .036). Total (T3: OR = 1.91, 95% CI 0.91-4.02, P-trend = .11) and free (T3: OR = 2.19, 95% CI 1.01-4.74, P-trend = .05) testosterone were positively associated with any core inflamed, especially free testosterone in men with waist circumference less than 102 cm (T3: OR = 3.51, 95% CI 1.03-12.11, P-trend = .05).

CONCLUSIONS

In this first study in men without prostate cancer and irrespective of clinical indication for biopsy, contrary to the hypothesis, circulating estrogens appeared to be inversely associated, especially in heavy men, whereas androgens appeared to be positively associated with intraprostatic inflammation.

Ipilimumab challenge/re-challenge in metastatic urothelial carcinoma (mUC) and other genitourinary (GU) tumors treated with cabozantinib+nivolumab (CaboNivo) or cabozantinib+nivolumab+ipilimumab (CaboNivoIpi)

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Background: We investigated challenging/re-challenging pts with ipilimumab (ipi) after progression on CaboNivo or CaboNivoIpi. Methods: In a phase I expansion study, patients with mUC post-platinum chemotherapy and other GU tumors patients who progressed on Cabo 40 mg daily plus nivolumab, 3 mg/kg every 21 days (CaboNivo) alone or with ipi, 1 mg/kg every 21 days for 4 cycles (CaboNivoIpi)-and achieved a PR or SD≥6 mo, were challenged/re-challenged with ipi, 1 mg/kg every 21 days for up to 4 cycles. Restaging scans were done every 6 wks for the first 12 wks, then every 8 wks and evaluated by RECIST 1.1. Results: In total, 24 patients were evaluated: 18 pts (8 UC (5 bladder and 3 upper tract), 4 clear cell renal cell carcinoma (RCC), 3 urachal adenocarcinoma (adeno), 2 bladder adeno, and 1 sarcomatoid clear cell RCC) who progressed on CaboNivo were challenged with ipi. In the challenge group, median (m) follow-up was 21.2 months. One pt achieved a PR in the LNs, but was found to have brain metastases before the next restaging, 13 had SD and 4 had PD. Median duration of PR or SD was 3.6 months (95% CI: 1.4 – 7.8 months). The mOS from start of ipi challenge was 13.9 months (95% CI: 5.8 months- not estimable); mPFS was 4.6 months (95% CI: 1.9 – 8.7 months). Grade 1/2 treatment related adverse events (AEs) occurred in all 18 pts (100%) and ≥Grade 3 (G≥3) AEs occurred in 11 pts (61%). The most common G≥3 AEs were hypophosphatemia (22%), hypertension (6%), adrenal insufficiency (6%), increased AST (6%), and ALT (6%). Six patients (3 bladder UC, 1 penile squamous cell (SCC) carcinoma, 1 urethral SCC, and 1 clear cell RCC with sarcomatoid features) who progressed on CaboNivoIpi were re-challenged with Ipi. On re-challenge, mfollow-up was 20.9 months. There were no PRs, 3 SDs and 3 PDs. mOS from start of re-challenge was 4.0 months (95% CI: 2.2 – 23.3 months) and mPFS was 1.9 months (95% CI: 1.1 – 2.6 months). Grade 1/2 treatment related AEs occurred in all 6 pts (100%) and ≥Grade 3 (G≥3) AEs occurred in 2pts (33%). G≥3 AEs included 1 hypertension (17%) and 1 hyperphosphatemia (17%). Conclusions: Ipi challenge/re-challenge showed low response rates in pts previously treated with CaboNivo or CaboNivoIpi. However, pts treated with CaboNivo who were challenged with ipi had a better OS than patients who had progressed on CaboNivoIpi and were re-challenged with ipi. Larger trials are warranted testing the ipi challenge in pts progressing on CaboNivo. Clinical trial information: NCT02496208 .

Phase I expansion study of cabozantinib plus nivolumab (CaboNivo) in metastatic urothelial carcinoma (mUC) patients (pts) with progressive disease following immune checkpoint inhibitor (ICI) therapy

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Background: Previous treatment with ICI is more common in clinical practice since recent FDA-approval of 5 ICIs in second-line and 2 in first-line for mUC. There is lack of data regarding the use of ICI after progression on a prior ICI. Cabozantinib has been shown to have immunomodulatory properties and may have synergistic effect with ICI. Methods: This is a phase I expansion cohort of mUC pts, who received prior ICI, treated with Cabozantinib 40mg daily and Nivolumab 3mg/kg every 2 weeks until disease progression/unacceptable toxicity. The primary objective was to determine the efficacy and tolerability of CaboNivo. Results: Twenty-nine mUC pts were treated. Median follow-up was 14.1 months (mo). The majority of pts were male (75.8%); 27 were White (93.1%), and 2 were Asian (6.9%). Primary tumor was bladder in 21 pts (72.4%) and upper tract in 8 (27.6%). Twenty-two pts (75.9%) had visceral metastasis (mets), 4 (13.8%) had lymph node only mets and 13 (44.8%) had liver mets. The median number of prior lines of treatment for mUC was 2 (range 0-8) with 17 pts (58.6%) receiving 2 prior lines of treatment. The majority of pts (86.2%) received prior chemotherapy for mUC and all pts received prior ICI. The median number of cycles of prior ICI was 7 (range 1-20) and median time between previous ICI and CaboNivo was 2.5 mo (range 1-18). The best response to previous ICI was partial response (PR) in 1 pt (3.4%), stable disease (SD) in 13 (44.9%), progressive disease (PD) in 14 (48.3%) and one (3.4%) was not evaluable (NE). The overall response rate for CaboNivo was 13.8% with 4 pts achieving PR (13.8%), 15 SD (51.7%), 7 PD (24.2%) and 3 NE (10.3%). Responses were seen in the liver, lung, and lymph nodes. Among 4 pts with PR, 2 were primary refractory to previous ICI and 2 had SD. At cutoff date the median duration of response was not reached and 3 PR were still ongoing: 1 had just began and the other 2 were ongoing at 12.3 and 26.4 mo. Among 15 pts with SD, 4 had SD for more than 6 mo and 2 were still ongoing at 8.1 and 25.1 mo. Median progression-free survival was 3.6 mo (95% CI: 2.1 – 5.3 mo) and median overall survival was 10 mo (95% CI: 5.8 – 16.7 mo). Grade 1/ 2 treatment related adverse events (AEs) occurred in 28 pts (97%) and >Grade 3 (G>3) AEs occurred in 14 pts (48%). The most common G>3 AEs were fatigue (14%), hypophosphatemia (14%), lymphocyte count decrease (14%), hypertension (7%) and hyponatremia (7%). Conclusions: CaboNivo is clinically active and safe in heavily pretreated pts with progressive mUC following ICI. Clinical trial information: NCT02496208 .

A phase IIa randomized placebo-controlled trial of pomegranate fruit extract/POMx in subjects with clinically localized prostate cancer undergoing active surveillance

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Background: Due to its high prevalence and often indolent natural history, prostate cancer(PC) active surveillance(AS) is an ideal setting for chemoprevention. Studies assessing pomegranate and its extracts have shown promising anti-proliferative and pro-apoptotic effects in cell lines and animal models and a single-arm clinical trial of pomegranate fruit extract(PFE) reported an increase in PSA doubling time(PSADT) during AS. The primary objective of this trial was to assess the effect of PFE supplementation on plasma levels of Insulin-like Growth Factor-1(IGF-1). Secondary objectives addressed PSA doubling time(PSADT), tumor volume on end-of-study(EOS) biopsy and plasma and prostate tissue biomarkers. Methods: Men with organ-confined favorable-risk PC on AS were randomly assigned to receive PFE 1,000 mg(n=15) or placebo(n=15) once daily for twelve months. Prostate biopsies were performed at study entry and upon completion of the one-year intervention. Tissue biomarkers were assessed by immunohistochemistry(IHC) with automated quantitation. Results: PFE was well-tolerated with no significant toxicities. One patient withdrew before study initiation and 29 completed the one-year intervention. No differences in plasma IGF-1 levels(p=0.5), PSADT, or tissue biomarkers of apoptosis or proliferation were observed. A significant increase in urolithin A(a urinary metabolite of pomegranate) was observed in the PFE arm. IHC analyses of both tumor (Table) and normal-appearing tissue adjacent to tumor showed reductions from baseline in IGF-1, 8-OHdG(DNA damage marker), and androgen receptor expression associated with PFE treatment. A trend towards a reduction in the maximum percent of biopsy core tumor involvement was observed(p=0.06) in PFE. Conclusions: PFE administration for 12-months was not associated with a decrease in plasma IGF-1 levels nor an increase in PSADT. However, exploratory analyses suggest that PFE may contain bioactive compounds capable of altering biomarkers in PC and normal-appearing adjacent tissue providing a rationale for further investigation of PFE in the active surveillance population.

A Magnetic Resonance Imaging-Based Prediction Model for Prostate Biopsy Risk Stratification

Importance

Multiparametric magnetic resonance imaging (MRI) in conjunction with MRI-transrectal ultrasound (TRUS) fusion-guided biopsies have improved the detection of prostate cancer. It is unclear whether MRI itself adds additional value to multivariable prediction models based on clinical parameters.

Objective

To determine whether an MRI-based prediction model can reduce unnecessary biopsies in patients with suspected prostate cancer.

Design, Setting, and Participants

Patients underwent MRI, MRI-TRUS fusion-guided biopsy, and 12-core systematic biopsy in 1 session. The development cohort used to derive the prediction model consisted of 400 patients from 1 institution enrolled between May 14, 2015, and August 31, 2016, and the validation cohort included 251 patients from 2 independent institutions who underwent biopsies between April 1, 2013, and June 30, 2016, at 1 institution and between July 1, 2015, and October 31, 2016, at the other institution. The MRI model included MRI-derived parameters in addition to clinical variables. Area under the curve of receiver operating characteristic curves and decision curve analysis were performed.

Main Outcomes and Measures

Risk of clinically significant prostate cancer on biopsy, defined as a Gleason score of 3 + 4 or higher in at least 1 biopsy core.

Results

Overall, 193 (48.3%) of the 400 patients in the development cohort (mean [SD] age at biopsy, 64.3 [7.1] years) and 96 (38.2%) of the 251 patients in the validation cohort (mean [SD] age at biopsy, 64.9 [7.2] years) had clinically significant prostate cancer, defined as a Gleason score greater than or equal to 3 + 4. By applying the model to the external validation cohort, the area under the curve increased from 64% to 84% compared with the baseline model (P < .001). At a risk threshold of 20%, the MRI model had a lower false-positive rate than the baseline model (46% [95% CI, 32%-66%] vs 92% [95% CI, 70%-100%]), with only a small reduction in the true-positive rate (89% [95% CI, 85%-96%] vs 99% [95% CI, 89%-100%]). Eighteen of 100 fewer biopsies could have been performed, with no increase in the number of patients with missed clinically significant prostate cancers.

Conclusions and Relevance

The inclusion of MRI-derived parameters in a risk model could reduce the number of unnecessary biopsies while maintaining a high rate of diagnosis of clinically significant prostate cancers.

A Randomized, Placebo-Controlled, Double-Blind, Dose Escalation, Single Dose, and Steady-State Pharmacokinetic Study of 9cUAB30 in Healthy Volunteers

9cUAB30 is a synthetic analogue of 9-cis retinoic acid with chemoprevention activity in cell lines and animal models. The purpose of this phase I placebo-controlled, double-blinded, dose escalation study of 9cUAB30 was to evaluate its safety, pharmacokinetics, and determine a dose for future phase II studies. Participants received a single dose of study drug (placebo or 9cUAB30) on day 1 followed by a 6-day drug-free period and then 28 days of continuous daily dosing starting on day 8. Fifty-three healthy volunteers were enrolled into five dose cohorts (20, 40, 80, 160, and 240 mg). Participants were randomized within each dose level to receive either 9cUAB30 (n = 8) or placebo (n = 2). 9cUAB30 was well tolerated, with no dose limiting toxicities reported and no evidence of persistent elevations in serum triglycerides or cholesterol. Treatment-emergent grade 3 hypertension occurred in 1 of 8 participants at the 20 mg dose level and in 2 of 8 at the 240 mg dose level, all considered unlikely related to study agent; no other grade 3 adverse events were observed. The AUC increased, as expected, between day 1 (single dose) and day 36 (steady state). Pharmacokinetics were linear in dose escalation through 160 mg. 9cUAB30 administered by daily oral dosing has a favorable safety and pharmacokinetic profile. On the basis of the observed safety profile and lack of linearity in pharmacokinetics at doses greater than 160 mg, the recommended phase II dose with the current formulation is 160 mg once daily.

Use of multiparametric magnetic resonance imaging and fusion-guided biopsies to properly select and follow African-American men on active surveillance

OBJECTIVES

To determine the rate of Gleason Grade Group (GGG) upgrading in African-American (AA) men with a prior diagnosis of low-grade prostate cancer (GGG 1 or GGG 2) on 12-core systematic biopsy (SB) after multiparametric magnetic resonance imaging (mpMRI) and fusion biopsy (FB); and whether AA men who continued active surveillance (AS) after mpMRI and FB fared differently than a predominantly Caucasian (non-AA) population.

PATIENTS AND METHODS

A database of men who had undergone mpMRI and FB was queried to determine rates of upgrading by FB amongst men deemed to be AS candidates based on SB prior to referral. After FB, Kaplan-Meier curves were generated for AA men and non-AA men who then elected AS. The time to GGG upgrading and time continuing AS were compared using the log-rank test.

RESULTS

AA men referred with GGG 1 disease on previous SB were upgraded to GGG ≥3 by FB more often than non-AA men, 22.2% vs 12.7% (P = 0.01). A total of 32 AA men and 258 non-AA men then continued AS, with a median (interquartile range) follow-up of 39.19 (24.24-56.41) months. The median time to progression was 59.7 and 60.5 months, respectively (P = 0.26). The median time continuing AS was 61.9 months and not reached, respectively (P = 0.80).

CONCLUSIONS

AA men were more likely to be upgraded from GGG 1 on SB to GGG ≥3 on initial FB; however, AA and non-AA men on AS subsequently progressed at similar rates following mpMRI and FB. A greater tendency for SB to underestimate tumour grade in AA men may explain prior studies that have shown AA men to be at higher risk of progression during AS.

MRI targeted biopsy dramatically increases detection of clinically significant prostate cancer while reducing the risk of indolent cancer detection

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Background: MRI fusion prostate biopsy has been shown to improve detection of clinically significant prostate cancer, however the degree of this benefit is poorly characterized in large clinical trials. Methods: 1750 MRI targeted plus sextant biopsies were performed in 1742 male patients from 2007 to 2017. Patient demographics, PSA, prostate volume, primary and secondary Gleason scores, Johns Hopkins Grade Groups, number of MRI targeted lesions, number of cores obtained, and biopsy yield were recorded. Results: The patient population consisted of men averaging 62.9-year-old (36-86) with a mean PSA 9.6ng/mL, and prostate volume of 59.2 ml. A total of 804 cancers were detected on sextant biopsy and 839 were detected on MRI targeted biopsy. Relative to targeted biopsy, sextant biopsy detected only significantly more Gleason 6 disease (14% vs 21.5%, p < 0.0001) than targeted biopsy. Targeted biopsy detected more Gleason 7 (21% vs 16.6%, p = 0.0009) and Gleason 8-10 (13.4% vs 9.4%). Additionally, Gleason 7 sub-stratification demonstrated substantially more Gleason 4+3 detection in targeted group vs sextant biopsy (4% vs 0.5%, p < 0.0001). When stratified by Grade Group targeted biopsy detected 76% more Grade Group 3-5 cancers (p < 0.0001) and 17.7% less Gleason Group 1-2 cancers (p < 0.0001). Only 1.7% of Grade Group 3-5 cancers were detected on sextant biopsy alone, where as 15.7% of Grade Group 3-5 cancers were detected on targeted biopsy alone. Conclusions: MRI targeted biopsy significantly increases the likelihood of detecting clinically significant cancer and decreases the risk of indolent cancer detection. These finding strongly support the use of MRI targeted biopsy when possible.

Predicting Gleason Group Progression for Men on Prostate Cancer Active Surveillance: Role of a Negative Confirmatory Magnetic Resonance Imaging-Ultrasound Fusion Biopsy

PURPOSE

Active surveillance has gained acceptance as an alternative to definitive therapy in many men with prostate cancer. Confirmatory biopsies to assess the appropriateness of active surveillance are routinely performed and negative biopsies are regarded as a favorable prognostic indicator. We sought to determine the prognostic implications of negative multiparametric magnetic resonance imaging-transrectal ultrasound guided fusion biopsy consisting of extended sextant, systematic biopsy plus multiparametric magnetic resonance imaging guided targeted biopsy of suspicious lesions on magnetic resonance imaging.

MATERIALS AND METHODS

All patients referred with Gleason Grade Group 1 or 2 prostate cancer based on systematic biopsy performed elsewhere underwent confirmatory fusion biopsy. Patients who continued on active surveillance after a positive or a negative fusion biopsy were followed. The baseline characteristics of the biopsy negative and positive cases were compared. Cox regression analysis was used to determine the prognostic significance of a negative fusion biopsy. Kaplan-Meier survival curves were used to estimate Grade Group progression with time.

RESULTS

Of the 542 patients referred with Grade Group 1 (466) or Grade Group 2 (76) cancer 111 (20.5%) had a negative fusion biopsy. A total of 60 vs 122 patients with a negative vs a positive fusion biopsy were followed on active surveillance with a median time to Grade Group progression of 74.3 and 44.6 months, respectively (p <0.01). Negative fusion biopsy was associated with a reduced risk of Grade Group progression (HR 0.41, 95% CI 0.22-0.77, p <0.01).

CONCLUSIONS

A negative confirmatory fusion biopsy confers a favorable prognosis for Grade Group progression. These results can be used when counseling patients about the risk of progression and for planning future followup and biopsies in patients on active surveillance.

Active surveillance of prostate cancer in African-Americans during the MRI era

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Background: Many patients with low-risk prostate cancer are encouraged by their physicians to pursue active surveillance (AS). AS has increasingly been utilized, however there remains anxiety by patients and their physicians that more aggressive disease will be missed and allowed to progress. African-American (AA) patients may present with more aggressive disease and higher rates of upgrading at the time of radical prostatectomy. Due to these factors, physicians may be hesitant to recommend AS to AA patients. We examined the role of AS in these patients in the era of MRI targeted biopsies. Methods: A prospectively maintained database was queried for all patients who underwent an MRI guided fusion biopsy from 2007 to 2016 and chose AS as their primary management strategy. Patents with Gleason Group (GG) 1 or 2 were eligible. Patients were then followed with yearly PSA, exam, MRI and biopsy if warranted. MRI Fusion biopsies were reviewed to determine any GG progression. Results: A total of 19 AA and 143 non-AA patients were reviewed with median follow up times of 31.63 (15.42 -89.50) and 30.87 (3.45 – 99.85) months, respectively. AA and non-AA patients had similar baseline PSA values (6.08 ± 2.93 vs. 5.89 ± 4.23, p = 0.85), proportion of GG 1 (15.89% vs 21.68%, p = 0.55) and PSA density (0.103 ± 0.041 vs. 0.123 ± 0.041, p = 0.36. However, AA patients did present at an earlier age (58.89 ± 6.64 vs. 63.69 ± 6.64, p = 0.004). A total of 8/19 (42.1%) AA and 46/143 (32.2%) non-AA had GG upgrading while on AS, p = 0.34. The median time until progression for AA and non-AA patients was 60.76 and 77.42 months, p = 0.68. Conclusions: In our study, AA men did begin AS at an earlier age than non-AA men. While both groups had statistically similar rates of progression, the relative risk of progression was higher in the AA cohort during this time period. Therefore, in the era of MRI and fusion biopsies we are better able to detect upgrading and somewhat mitigate the the risks associated with upgrading during AS irrespective of race but larger studies are needed to determine whether there are meaningful differences in the rates of progression between AA and non-AA men. This research was supported by the Intramural Research Program of the National Cancer Institute, NIH.

Results of phase I plus expansion cohorts of cabozantinib (Cabo) plus nivolumab (Nivo) and CaboNivo plus ipilimumab (Ipi) in patients (pts) with with metastatic urothelial carcinoma (mUC) and other genitourinary (GU) malignancies

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Background: Tolerability and efficacy of CaboNivo and CaboNivoIpi were demonstrated in the initial phase I cohort, prompting longer follow-up and the addition of expansion cohorts to further evaluate both combinations Methods: Phase I cohort had 7 dose levels (DL). Recommended phase 2 doses for CaboNivo=Cabo 40mg/Nivo 3mg/kg (DL2) & CaboNivoIpi=Cabo 40mg/Nivo 3mg/kg/Ipi 1mg/kg (DL6) (Nadal ESMO 2017).In expansion cohorts, pts were treated: [1] DL8: Cabo 40mg/Nivo 1mg/kg/Ipi 3mg/kg; [2]DL2: mUC, metastatic renal cell carcinoma (mRCC), adenocarcinoma bladder (AcB): post-PD-1-PDL1 inhibitor mUC (p-mUC), and [3] DL6 mRCC. Objectives: safety, objective response rate (ORR), duration of response (DOR), progression-free survival (PFS) & overall survival (OS). Results: 75 pts enrolled. Median age 59 yo. 83% male, 17% female. 47 treated with CaboNivo (mUC n=24; AcB n= 9; germ cell tumor (GCT) n= 5; castrate-resistant prostate cancer (CRPC) n= 4; bladder squamous cell carcinoma (SCC) n= 2; penile n=1; mRCC n= 7). 28 treated with CaboNivoIpi: (mUC n=8; penile n=3; CRPC n=7; Sertoli n=1; mRCC n=6; bladder small cell carcinoma n=1; renal medullary carcinoma (RMC) n=2). Any grade (G) adverse events (AEs) (CaboNivo 96% & CaboNivoIpi 96%)/G3–4 AEs (CaboNivo 62% & CaboNivoIpi 71%). Most common any G, CaboNivo: fatigue 70%, diarrhea 60%, AST/ALT 60%, hypophosphatemia (hypoP) 45% & CaboNivoIpi: fatigue 71%, diarrhea 68%, hypoP 50%, AST/ALT 43%. Most common G3-4, CaboNivo: lipase 17%, hypoP 15%, fatigue 6% & CaboNivoIpi: hypoP 21%, AST/ALT 14%, lipase 14%. Selected irAs: colitis (2.6%), hepatitis (2.6%), pneumonitis (2.6%), aseptic meningitis (1.3%). ORR: 36%; 3CR (2mUC, 1SCC) & 20PR (5mUC, 2SCC, 7mRCC, 2Penile, 2AcB, 1CRPC, 1RMC). mDOR: 24.1 mo [95% CI: 14.7-NR], mPFS: 7.2 mo [95%CI: 5.1-18.4], mOS:18.8 mo [95%CI: 10.6-NR]. OS 6/12 mo: 83%/61%. Cohort of p-mUC pts(n=5):1PR/3SD/1PD Conclusions: Updated results from phase I and expanded cohorts confirm initial safety findings and promising antitumor activity for both combinations in mUC, mRCC, and rare GU malignancies Clinical trial information: NCT02496208.

Active surveillance criteria in the age of targeted biopsies

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Background: Many urologists are now using active surveillance (AS) to manage patients with low-risk prostate cancer. A variety of criteria have been proposed to select patients for AS. A key feature of these criteria is Gleason Group as determined by systematic or “random” biopsies (SB). In this study, we examined the progression of Gleason Group (GG) detected only on SB compared to patients with positive MRI-fusion or “targeted” biopsies (FB). Methods: A prospectively maintained database was queried for all patients who underwent an MRI guided FB and SB from 2007 to 2016 and chose AS as their primary management strategy. Patents with GG 1 or 2 were eligible. Patients were then followed with yearly PSA, exam, MRI and biopsy if warranted. FBs were reviewed to determine GG progression. We divided patients into those who had cancer detected on SB only and those who had positive FBs with or without a positive SB. Results: A total of 162 patients met our criteria with 73 having an initial positive FB and 89 having cancer only on SB and a negative FB. Median follow-up was 27.62 (4.14 – 96.56) and 33.83 (3.45-99.84) months, respectively. The two groups were similar in age (64.49 ± 6.57 vs. 62.08 ± 6.92 years, p = 0.03) and PSA (6.23 ± 4.23 vs. 5.67 ± 3.98 ng/ml, p = 0.39). The median time to pathologic progression for GG 1 patients with initial FB positive was 53.88 months and those with GG 1 on initial SB was 80.81 months (p = 0.003). The median time to pathologic progression for GG 2 patients with initial FB positive was 36.26 months and those with GG 2 on initial SB was 76.01 months (p = 0.099). Conclusions: Previously accepted AS criteria have been based on SBs. However, those patients placed on AS after a positive FB progressed fast than cancer detected only on SB. With MRI and FBs more routinely used in clinical practice, clinicians could use this information from FBs to better stratify and closely monitor patients during AS. This research was supported by the Intramural Research Program of the National Cancer Institute, NIH.

A Prospective Study of Chronic Inflammation in Benign Prostate Tissue and Risk of Prostate Cancer: Linked PCPT and SELECT Cohorts

Background: We leveraged two trials to test the hypothesis of an inflammation-prostate cancer link prospectively in men without indication for biopsy.Methods: Prostate Cancer Prevention Trial (PCPT) participants who had an end-of-study biopsy performed per protocol that was negative for cancer and who subsequently enrolled in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) were eligible. We selected all 100 cases and sampled 200 frequency-matched controls and used PCPT end-of-study biopsies as "baseline." Five men with PSA > 4 ng/mL at end-of-study biopsy were excluded. Tissue was located for 92 cases and 193 controls. We visually assessed inflammation in benign tissue. We estimated ORs and 95% confidence intervals (CI) using logistic regression adjusting for age and race.Results: Mean time between biopsy and diagnosis was 5.9 years. In men previously in the PCPT placebo arm, 78.1% of cases (N = 41) and 68.2% of controls (N = 85) had at least one baseline biopsy core (∼5 evaluated per man) with inflammation. The odds of prostate cancer (N = 41 cases) appeared to increase with increasing mean percentage of tissue area with inflammation, a trend that was statistically significant for Gleason sum <4+3 disease (N = 31 cases; vs. 0%, >0-<1.8% OR = 1.70, 1.8-<5.0% OR = 2.39, ≥5% OR = 3.31, P_trend = 0.047). In men previously in the finasteride arm, prevalence of inflammation did not differ between cases (76.5%; N = 51) and controls (75.0%; N = 108).Conclusions: Benign tissue inflammation was positively associated with prostate cancer.Impact: This first prospective study of men without biopsy indication supports the hypothesis that inflammation influences prostate cancer development. Cancer Epidemiol Biomarkers Prev; 26(10); 1549-57. ©2017 AACR.

Association between variants in genes involved in the immune response and prostate cancer risk in men randomized to the finasteride arm in the Prostate Cancer Prevention Trial

BACKGROUND

We reported that some, but not all single nucleotide polymorphisms (SNPs) in select immune response genes are associated with prostate cancer, but not individually with the prevalence of intraprostatic inflammation in the Prostate Cancer Prevention Trial (PCPT) placebo arm. Here, we investigated whether these same SNPs are associated with risk of lower- and higher-grade prostate cancer in men randomized to finasteride, and with prevalence of intraprostatic inflammation among controls. Methods A total of 16 candidate SNPs in IL1β, IL2, IL4, IL6, IL8, IL10, IL12(p40), IFNG, MSR1, RNASEL, TLR4, and TNFA and 7 tagSNPs in IL10 were genotyped in 625 white prostate cancer cases, and 532 white controls negative for cancer on an end-of-study biopsy nested in the PCPT finasteride arm. We used logistic regression to estimate log-additive odds ratios (OR) and 95% confidence intervals (CI) adjusting for age and family history.

RESULTS

Minor alleles of rs2243250 (T) in IL4 (OR = 1.46, 95% CI 1.03-2.08, P-trend = 0.03), rs1800896 (G) in IL10 (OR = 0.77, 95% CI 0.61-0.96, P-trend = 0.02), rs2430561 (A) in IFNG (OR = 1.33, 95% CI 1.02-1.74; P-trend = 0.04), rs3747531 (C) in MSR1 (OR = 0.55, 95% CI 0.32-0.95; P-trend = 0.03), and possibly rs4073 (A) in IL8 (OR = 0.81, 95% CI 0.64-1.01, P-trend = 0.06) were associated with higher- (Gleason 7-10; N = 222), but not lower- (Gleason 2-6; N = 380) grade prostate cancer. In men with low PSA (<2 ng/mL), these higher-grade disease associations were attenuated and/or no longer significant, whereas associations with higher-grade disease were apparent for minor alleles of rs1800795 (C: OR = 0.70, 95% CI 0.51-0.94, P-trend = 0.02) and rs1800797 (A: OR = 0.72, 95% CI 0.53-0.98, P-trend = 0.04) in IL6. While some IL10 tagSNPs were associated with lower- and higher-grade prostate cancer, distributions of IL10 haplotypes did not differ, except possibly between higher-grade cases and controls among those with low PSA (P = 0.07). We did not observe an association between the studied SNPs and intraprostatic inflammation in the controls.

CONCLUSION

In the PCPT finasteride arm, variation in genes involved in the immune response, including possibly IL8 and IL10 as in the placebo arm, may be associated with prostate cancer, especially higher-grade disease, but not with intraprostatic inflammation. We cannot rule out PSA-associated detection bias or chance due to multiple testing.

A phase I study of cabozantinib plus nivolumab (CaboNivo) and cabonivo plus ipilimumab (CaboNivoIpi) in patients (pts) with refractory metastatic (m) urothelial carcinoma (UC) and other genitourinary (GU) tumors

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Background: We report the safety and clinical activity of the combination of CaboNivo and CaboNivoIpi in pts with mUC and other mGU tumors (NCT02496208). Methods: In this phase I trial 30 pts were treated in 4 dose levels (DL) for part 1 (CaboNivo) and 18 pts were treated in 3 DL for part 2 (CaboNivoIpi). Pts received Cabo PO daily and Nivo IV (part 1) with Ipi 1mg/kg x 4 doses q3wks (part 2). A mUC and a renal cell carcinoma (RCC) expansion cohort of CaboNivo has initiated enrollment. Tumors were assessed for overall response rate (ORR) q8wks (RECIST 1.1). Adverse events (AEs) were graded (G) by NCI-CTCAE v4.0. Results: From 7/22/15 to 12/31/2016, 48pts (CaboNivo N = 30; CaboNivoIpi N = 18) (mUC N = 19; bladder urachal N = 4; bladder squamous cell carcinoma (bSCC) N = 2; germ cell tumor (GCT) N = 4; castrate-resistant prostate cancer (CRPC) N = 9; RCC N = 2, sarcomatoid RCC N = 2, Sertoli cell N = 1, and trophoblastic tumor N = 1 were treated. Median age was 58 (range 35-77), 41 (85%) were male. Common treatment-related G1/2 AEs for CaboNivo: ALT increase (67%), fatigue (63%), diarrhea (60%), hypothyroidism (57%); CaboNivoIpi: fatigue (72%), diarrhea (61%), anorexia (61%); Grade 3 AEs for CaboNivo: hypertension (23%), neutropenia (17%), hypophosphatemia (13%), lipase increase (10%), fatigue (7%), aseptic meningitis (3%); CaboNivoIpi: hypophosphatemia (19%), hypertension (19%), fatigue (13%), hyponatremia (13%), nausea (13%), lipase increase (11%), colitis (6%); G4 CaboNivo: lipase increase (7%) thrombocytopenia (3%); CaboNivoIpi lipase increase (6%) There were no G5 toxicities, no DLTs. 43 pts were evaluable for response: ORR was 30% 13/43 [3 CR (2 mUC, 1 bSCC); 10 PRs (4 mUC, 2 penile, 1 sarcomatoid RCC, 1 urachal, 1 CRPC, 1 bSCC)]. ORR for CaboNivo 39% (mUC 44%); CaboNivoIpi 18% (mUC 29%). 11/13 (85%) of responses were ongoing at cutoff. Conclusions: CaboNivo and CaboNivoIpi combinations were well tolerated with no DLTs and have durable efficacy in mGU tumors particularly mUC. Rare tumors such as bSCC, urachal, and penile cancers demonstrated response to the combination. Larger cohorts of mUC and rare GU tumors are ongoing. Clinical trial information: NCT02496208.

A Phase II Randomized, Double-blind, Presurgical Trial of Polyphenon E in Bladder Cancer Patients to Evaluate Pharmacodynamics and Bladder Tissue Biomarkers

We performed a phase II pharmacodynamic prevention trial of Polyphenon E [a green tea polyphenol formulation primarily consisting of epigallocatechin gallate (EGCG)] in patients prior to bladder cancer surgery. Patients with a bladder tumor were randomized to receive Polyphenon E containing either 800 or 1,200 mg of EGCG or placebo for 14 to 28 days prior to transurethral resection of bladder tumor or cystectomy. The primary objective was to compare the postintervention EGCG tissue levels in patients receiving Polyphenon E as compared with placebo. Secondary objectives included assessments of tissue expression of PCNA, MMP2, clusterin, VEGF, p27, IGF-1, IGFBP-3; correlation of tissue, plasma, and urine levels of EGCG; and EGCG metabolism by catechol-O-methyltransferase and UDP-glucuronosyltransferase pharmacogenomic mutations. Thirty-one patients (male:female, 26:5; mean age, 67.2 years) were randomized and 29 (94%) completed the study. There was not an observed significant difference (P = 0.12) in EGCG tissue levels between two Polyphenon E dosage groups combined versus placebo. However, a dose-response relationship for EGCG levels was observed in both normal (P = 0.046) and malignant bladder tissue (P = 0.005) across the three study arms. In addition, EGCG levels in plasma (P < 0.001) and urine (P < 0.001) increased and PCNA (P = 0.016) and clusterin (P = 0.008) were downregulated in a dose-dependent fashion. No pharmacogenomic relationship was observed. EGCG levels in plasma, urine, and bladder tissue followed a dose-response relationship, as did modulation of tissue biomarkers of proliferation and apoptosis. Despite the limitations of this pilot study, the observed pharmacodynamics and desirable biologic activity warrant further clinical studies of this agent in bladder cancer prevention. Cancer Prev Res; 10(5); 298-307. ©2017 AACR.

Assessing bone response to cabozantinib in patients (pts) with metastatic urothelial carcinoma (mUC) using 18F-Sodium Fluoride (NaF) PET/CT

328

Background: NaF PET/CT is a radiotracer used for the assessment of bone metastases (mets). The goal of our study was to assess bone mets using NaF PET/CT imaging in mUC pts treated with cabozantinib. Methods: We conducted a single-arm phase II trial of cabozantinib in pts with mUC. Pts with known bone mets underwent a NaF PET/CT scan at baseline and every 8 weeks until progression. At each scan, we captured, the number of lesions per pt and per anatomical site, the maximum standardized uptake values (SUV), and serum alkaline phosphatase (AP). Bone responses (bone response (BR), stable disease (SD), progressive disease (PD)) were assigned to each pt based on the NaF report. Change from baseline to the time of best response for SUV, the number of lesions, and AP were compared between BR + SD vs PD were analyzed using an exact Wilcoxon rank sum test. The Kaplan-Meier method was used to determine the association of progression free survival (PFS) or overall survival (OS) with baseline SUV and number of lesions. Results: 68 pts enrolled on study, 22 pts had bone mets at baseline (6 bone only and 16 with bone and soft-tissue mets) (median OS 4.6 mo (95% CI: 3.4-7.7 mo), and median PFS 2.0 mo (95% CI: 1.8-3.9 mo)) of which 15 pts had follow up NaF scans. At baseline, 147 total lesions were analyzed, and the lesion distribution was: spine 29%, ribs 21%, pelvis 18%, skull 11%, femur 6%, scapula 3%, humerus 3%, sternum 3%, sacrum 3%, fibula 1%, and clavicle 0.7%. 5/15 pts had BR (and remained on study 238, 252, 182, 161, and 56 days), 4/15 SD, and 6/15 PD at best response. Sites of PD occurred in bone 10/22, bone and soft-tissue 5/22, and soft-tissue 7/22. The percent difference in number of lesions among responders and non-responders was 43% (p = 0.0039). At baseline, there was no association with PFS or OS and number of lesions (p = 0.84, p = 0.97), SUV (p = 0.83, p = 0.97), or AP (p = 0.97, p = 0.33). Conclusions: Pts with mUC and bone disease have poor overall outcome. Most bone lesions were found in the spine, ribs, and pelvis. Larger studies are needed to assess the correlation of NaF response with clinical outcome in mUC. We have an ongoing study using NaF PET to assess bone mets in mUC treated with cabozantinib/nivolumab/ipilimumab. Clinical trial information: NCT01688999.

A phase I study of cabozantinib plus nivolumab (CaboNivo) and ipilimumab (CaboNivoIpi) in patients (pts) with refractory metastatic urothelial carcinoma (mUC) and other genitourinary (GU) tumors

293

Background: We report the safety and clinical activity of CaboNivo and CaboNivoIpi in pts with mUC and other GU tumors. Methods: Part I included 4 dose levels (DLs) (Cabo PO daily and Nivo IV q2wk): DL1 Cabo40/Nivo1, DL2 Cabo40/Nivo3, DL3 Cabo60/Nivo1, DL4 Cabo 60/Nivo3. Part II included 3 DLs (Cabo PO daily, plus NivoIpi IV q3 wk x 4 doses then Nivo q2wk): DL5 Cabo 40/Nivo1/Ipi1, DL6 Cabo40/Nivo3/Ipi1, DL7 Cabo 60/Nivo3/Ipi 1. Tumors were assessed for overall response rate (ORR) by RECIST 1.1. Adverse events (AEs) were graded (G) by NCI-CTCAE v4.0. Results: From 7/22/15-10/14/16, 40pts [mUC N=14/(plasmacytoid N=1); bladder urachal N=4; bladder squamous cell carcinoma (bSCC) N=2; germ cell tumor (GCT) N=4; castrate-resistant prostate cancer (CRPC) N=9/(neuroendocrine prostate N=1); sarcomatoid renal cell carcinoma (sRCC) N=1; trophoblastic tumor N=1); sertoli cell tumor N=1; and penile SCC N=4] were treated. Median age was 58 (range 31-77); 36 (90%) were male. AEs related to study drugs with [1] CaboNivo included G3 hyponatremia 4/24 (17%), hypophosphatemia 4/24 (17%), lipase increase 3/24 (13%), dehydration 2/24 (8%), diarrhea 2/24 (8%), fatigue 2/24 (8%), HTN 2/24 (8%), thromboembolic event 1/24 (4%), rash 1/24 (4%), chest pain 1/24 (4%), amylase increase 1/24 (4%), hyperthyroid 1/24 (4%), proteinuria 1/24 (4%), thrombocytopenia 1/24 (4%); and G4 pyelonephritis 1/24 (4%); [2] CaboNivoIpi included G3 hypophosphatemia 2/16 (13%), lipase increase 2/16 (13%), fatigue 1/16 (6%), ALT increase 1/16 (6%), and HTN 1/16 (6%). There were 2/40 (5%) G3 immune-related AEs: 1 aseptic meningitis/CaboNivo; and 1 colitis/CaboNivoIpi. There were no G5 toxicities, or DLTs. 38 pts were evaluable for response. ORR was 12/38 (32%): 1 CR (bSCC); 11 PRs (5 mUC, 1 sRCC, 1 urachal, 1 bSCC, 1 CRPC, 2 penile). SD 20/38 (53%); 9/11 responses were ongoing and 26/39 (67%) pts remain on study. Conclusions: CaboNivo and CaboNivoIpi were well tolerated with no DLTs. Responses were seen at all DLs. The recommended dose for Part I is Cabo40/Nivo3 and for Part II is Cabo40/Nivo3/Ipi1. Rare tumors such as bSCC, urachal, and penile cancer demonstrated responses. Clinical trial information: NCT02496208.

18F-FDG-PET/CT imaging to assess response to treatment with cabozantinib at 4 weeks versus 8 weeks of therapy in patients (pts) with metastatic urothelial carcinoma (mUC)

317

Background: This study investigates whether changes in 18F-FDG-PET/CT correlate with response to cabozantinib at an early time point (4 wks) versus the conventional time point of restaging (8 wks) in pts with mUC, using Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST). Methods: 68 pts with mUC in a single arm phase II clinical trial of cabozantinib underwent FDG-PET/CT scans at baseline, 4 and 8 wks. Up to 5 lesions with the highest Standard Uptake Value (SUV) were designated as target lesions. Response was determined using 2 versions of PERCIST (1 lesion vs top 5 lesions with highest FDG uptake) for FDG-PET/CT at 4 and 8 wks. PERCIST response classifications were compared to RECIST v1.1 at 8 wks. Results: 54 pts had evaluable disease. The single lesion 4 wk response by PERCIST showed 40% partial metabolic response (PMR), 33% stable metabolic disease (SMD), and 27% progressive metabolic disease (PMD). The single lesion 8 wk response by PERCIST showed 31% PMR, 31% SMD, and 38% PMD. The single lesion analysis coincided with multiple lesion PERCIST analysis in 86% of pts at 4 wks and 89% at 8 wks. The 4 wk PET/CT was predictive of the 8 wk PET/CT in 75% of single lesion and 76% of multiple lesion analyses. In lesion-based analysis, the 4 wk PET/CT was predictive of the 8 wk PET/CT in 74% of bone, 89% of lung, 77% of lymph node, 74% of soft tissue, and 58% of liver lesions. Only 42% of the 8 wk PERCIST and RECIST classifications coincided. At 8 wks, 40% showed response in FDG PET-CT restaging vs 7% complete/partial response by RECIST. Conclusions: The 4 wk PET/CT scan predicts the therapy response at the 8 wk PET/CT scan however the 4 wk scan overestimates the 8 wk response. The single lesion analysis by PERCIST correlates with the multiple lesion analysis and may have more clinical utility. In the lesion-based analysis, the 4 wk PET/CT scan is predictive of the 8 wk PET/CT for bone, lung, lymph node and soft tissue but not for liver lesions. Response classifications by PERCIST are not in agreement with response classifications by RECIST. Although the methods may be complementary, they are not interchangeable. Further studies are required to validate these findings. Clinical trial information: NCT01688999.

Phase IIa, randomized placebo-controlled trial of single high dose cholecalciferol (vitamin D3) and daily Genistein (G-2535) versus double placebo in men with early stage prostate cancer undergoing prostatectomy

INTRODUCTION AND OBJECTIVES

Prostate cancer (PCa) represents an important target for chemoprevention given its prolonged natural history and high prevalence. Epidemiologic and laboratory data suggest that vitamin D and genistein (soy isoflavone) may decrease PCa progression. The effect of vitamin D on prostate epithelial cell proliferation and differentiation is well documented and genistein may augment this affect through inhibition of the CYP24 enzyme, which is responsible for intracellular vitamin D metabolism. In addition, both genistein and vitamin D inhibit the intraprostatic synthesis of prostaglandin E2, an important mediator of inflammation. The objectives of this prospective multicenter trial were to compare prostate tissue calcitriol levels and down-stream related biomarkers in men with localized prostate cancer randomized to receive cholecalciferol and genistein versus placebo cholecalciferol and placebo genistein during the pre-prostatectomy period.

METHODS

Men undergoing radical prostatectomy were randomly assigned to one of two treatment groups: (1) cholecalciferol (vitamin D₃) 200,000 IU as one dose at study entry plus genistein (G-2535), 600 mg daily or (2) placebo cholecalciferol day 1 and placebo genistein PO daily for 21-28 days prior to radical prostatectomy. Serum and tissue analyses were performed and side-effects recorded.

RESULTS

A total of 15 patients were enrolled, 8 in the placebo arm and 7 in the vitamin D₃ + genistein (VD + G) arm. All patients were compliant and completed the study. No significant differences in side effect profiles were noted. Utilization of the VD + G trended toward increased calcitriol serum concentrations when compared to placebo (0.104 ± 0.2 vs. 0.0013 ± 0.08; p=0.08); however, prostate tissue levels did not increase. Calcidiol levels did not change (p=0.5). Immunohistochemistry for marker analyses using VECTRA automated quantitation revealed a increase in AR expression (p=0.04) and a trend toward increased TUNEL staining (p=0.1) in prostate cancer tissues in men randomized to receive VD + G compared to placebo.

CONCLUSIONS

In this first study testing the combination of a single, large dose of cholecalciferol and daily genistein, the agents were well tolerated. While an increase in AR expression suggesting differentiation was observed, it is difficult to draw firm conclusions regarding the bioactivity of the combination given the sample size.

Abstract 812: Association between variants in genes involved in the immune response and prostate cancer risk in men randomized to finasteride in the Prostate Cancer Prevention Trial

Background: We reported that some, but not all single nucleotide polymorphisms (SNPs) in select immune response genes are associated with prostate cancer in the Prostate Cancer Prevention Trial* (PCPT) placebo arm. Here, we investigated whether these same SNPs are associated with risk in men randomized to finasteride, which is known to increase intraprostatic inflammation. Methods: 16 candidate SNPs in IL1, IL2, IL4, IL6, IL8, IL10, IL12(p40), IFNG, MSR1, RNASEL, TLR4, and TNFA and 7 tagSNPs in IL10 were genotyped in 625 prostate cancer cases, and 532 controls negative for cancer on an end-of-study biopsy nested in the PCPT finasteride arm. Cases and controls were non-Hispanic white men. We used logistic regression to estimate log-additive odds ratios (OR) and 95% confidence intervals (CI) adjusting for age and family history (matching factors). Results: Minor alleles of rs2243250 (T) in IL4 (OR = 1.46, 95% CI 1.03-2.08, P-trend = 0.03), rs1800896 (G) in IL10 (OR = 0.77, 95% CI 0.61-0.96, P-trend = 0.02), rs2430561 (A) in IFNG (OR = 1.33, 95% CI 1.02-1.74; P-trend = 0.04), rs3747531 (C) in MSR1 (OR = 0.55, 95% CI 0.32-0.95; P-trend = 0.03), and possibly rs4073 (A) in IL8 (OR = 0.81, 95% CI 0.64-1.01, P-trend = 0.06) were associated with higher- (Gleason 7-10; N = 222), but not lower- (Gleason 2-6; N = 380) grade prostate cancer. In men with low PSA (&lt;2 ng/mL), these associations were attenuated and/or no longer significant, whereas inverse associations with higher-grade disease were apparent for minor alleles of rs1800795 (C: OR = 0.70, 95% CI 0.51-0.94, P-trend = 0.02) and rs1800797 (A: OR = 0.72, 95% CI 0.53-0.98, P-trend = 0.04) in IL6. While some IL10 tagSNPs were associated with lower- and higher-grade prostate cancer, distributions of IL10 haplotypes did not differ from controls, except possibly among those with low PSA (P = 0.07). Conclusion: In the PCPT finasteride arm, variation in genes involved in the immune response, including possibly IL8 and IL10 as in the placebo arm, may be associated with prostate cancer, especially higher-grade disease, but we cannot rule out PSA-associated detection bias or chance due to multiple testing.Funding: P01 CA108964, U10 CA37429, UM1 CA182883, T32 CA009314. *A SWOG-Coordinated Study S9217

Citation Format: Danyelle A. Winchester, Cathee Till, Jianfeng Xu, Ian M. Thompson, Scott M. Lippmann, Howard L. Parnes, Angelo M. De Marzo, Charles G. Drake, Elizabeth A. Platz, The PCPT P01 Project 4 Research Team. Association between variants in genes involved in the immune response and prostate cancer risk in men randomized to finasteride in the Prostate Cancer Prevention Trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 812.

TARP vaccination is associated with slowing in PSA velocity and decreasing tumor growth rates in patients with Stage D0 prostate cancer

T-cell receptor alternate reading frame protein (TARP) is a 58-residue protein over-expressed in prostate and breast cancer. We investigated TARP peptide vaccination's impact on the rise in PSA (expressed as Slope Log(PSA) or PSA Doubling Time (PSADT)), validated tumor growth measures, and tumor growth rate in men with Stage D0 prostate cancer. HLA-A*0201 positive men were randomized to receive epitope-enhanced (29-37-9V) and wild-type (27-35) TARP peptides administered as a Montanide/GM-CSF peptide emulsion or as an autologous peptide-pulsed dendritic cell vaccine every 3 weeks for a total of five vaccinations with an optional 6th dose of vaccine at 36 weeks based on immune response or PSADT criteria with a booster dose of vaccine for all patients at 48 and 96 weeks. 41 patients enrolled with median on-study duration of 75 weeks at the time of this analysis. Seventy-two percent of patients reaching 24 weeks and 74% reaching 48 weeks had a decreased Slope Log(PSA) compared to their pre-vaccination baseline (p = 0.0012 and p = 0.0004 for comparison of overall changes in Slope Log(PSA), respectively). TARP vaccination also resulted in a 50% decrease in median tumor growth rate (g): pre-vaccine g = 0.0042/day, post-vaccine g = 0.0021/day (p = 0.003). 80% of subjects exhibited new vaccine-induced TARP-specific IFNγ ELISPOT responses but they did not correlate with decreases in Slope Log(PSA). Thus, vaccination with TARP peptides resulted in significant slowing in PSA velocity and reduction in tumor growth rate in a majority of patients with PSA biochemical recurrence.

Association of androgen metabolism gene polymorphisms with prostate cancer risk and androgen concentrations: Results from the Prostate Cancer Prevention Trial

BACKGROUND

Prostate cancer is highly influenced by androgens and genes. The authors investigated whether genetic polymorphisms along the androgen biosynthesis and metabolism pathways are associated with androgen concentrations or with the risk of prostate cancer or high-grade disease from finasteride treatment.

METHODS

A nested case-control study from the Prostate Cancer Prevention Trial using data from men who had biopsy-proven prostate cancer (cases) and a group of biopsy-negative, frequency-matched controls was conducted to investigate the association of 51 single nucleotide polymorphisms (SNPs) in 12 genes of the androgen pathway with overall (total), low-grade, and high-grade prostate cancer incidence and serum hormone concentrations.

RESULTS

There were significant associations of genetic polymorphisms in steroid 5α-reductase 1 (SRD5A1) (reference SNPs: rs3736316, rs3822430, rs1560149, rs248797, and rs472402) and SRD5A2 (rs2300700) with the risk of high-grade prostate cancer in the placebo arm of the Prostate Cancer Prevention Trial; 2 SNPs were significantly associated with an increased risk (SRD5A1 rs472402 [odds ratio, 1.70; 95% confidence interval, 1.05-2.75; Ptrend = .03] and SRD5A2 rs2300700 [odds ratio, 1.94; 95% confidence interval, 1.19-3.18; Ptrend = .01]). Eleven SNPs in SRD5A1, SRD5A2, cytochrome P450 family 1, subfamily B, polypeptide 1 (CYP1B1), and CYP3A4 were associated with modifying the mean concentrations of serum androgen and sex hormone-binding globulin; and 2 SNPs (SRD5A1 rs824811 and CYP1B1 rs10012; Ptrend < .05) consistently and significantly altered all androgen concentrations. Several SNPs (SRD5A1 rs3822430, SRD5A2 rs2300700, CYP3A43 rs800672, and CYP19 rs700519; Ptrend < .05) were significantly associated with both circulating hormone levels and prostate cancer risk.

CONCLUSIONS

Germline genetic variations of androgen-related pathway genes are associated with serum androgen concentrations and the risk of prostate cancer. Further studies to examine the functional consequence of novel causal variants are warranted. Cancer 2016;122:2332-2340. © 2016 American Cancer Society.

Key genes involved in the immune response are generally not associated with intraprostatic inflammation in men without a prostate cancer diagnosis: Results from the prostate cancer prevention trial

BACKGROUND

We previously reported that both intraprostatic inflammation and SNPs in genes involved in the immune response are associated with prostate cancer risk and disease grade. In the present study, we evaluated the association between these SNPs and intraprostatic inflammation in men without a prostate cancer diagnosis.

METHODS

Included in this cross-sectional study were 205 white controls from a case-control study nested in the placebo arm of the Prostate Cancer Prevention Trial. We analyzed inflammation data from the review of H&E-stained prostate tissue sections from biopsies performed per protocol at the end of the trial irrespective of clinical indication, and data for 16 SNPs in key genes involved in the immune response (IL1β, IL2, IL4, IL6, IL8, IL10, IL12(p40), IFNG, MSR1, RNASEL, TLR4, TNFA; 7 tagSNPs in IL10). Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between carrying at least one minor allele and having at least one biopsy core (of a mean of three reviewed) with inflammation.

RESULTS

None of the SNPs evaluated was statistically significantly associated with having at least one core with inflammation. However, possible inverse associations were present for carrying the minor allele of rs2069762 (G) in IL2 (OR = 0.51, 95%CI 0.25-1.02); carrying two copies of the minor allele of rs1800871 (T) of IL10 (OR = 0.29, 95%CI 0.08-1.00); and carrying the minor allele of rs486907 (A) in RNASEL (OR = 0.52, 95%CI 0.26-1.06). After creating a genetic risk score from the three SNPs possibly associated with inflammation, the odds of inflammation increased with increasing number of risk alleles (P-trend = 0.008).

CONCLUSION

While our findings do not generally support a cross-sectional link between individual SNPs in key genes involved in the immune response and intraprostatic inflammation in men without a prostate cancer diagnosis, they do suggest that some of these variants when in combination may be associated with intraprostatic inflammation in benign tissue.

Efficiency of Prostate Cancer Diagnosis by MR/Ultrasound Fusion-Guided Biopsy vs Standard Extended-Sextant Biopsy for MR-Visible Lesions

BACKGROUND

Use of magnetic resonance (MR) imaging to improve prostate biopsy efficiency is rapidly gaining in popularity. The aim of this study was to assess the biopsy efficiency of MR/ultrasound (MR/US) fusion-guided ("targeted") biopsies vs extended-sextant 12-core ("standard") biopsies for overall and high-grade prostate cancer detection.

METHODS

From August 2007 to February 2014, 1003 men were enrolled in a prospective trial comparing the diagnostic yield of targeted and standard prostate biopsies performed during the same session. A total of 17 619 biopsy cores were reviewed. Biopsy efficiency was determined by dividing the total number of cores by the number of positive cores obtained. All statistical tests were two-sided.

RESULTS

A mean of 12.3 (95% confidence interval [CI] = 12.2 to 12.3) standard and 5.3 (95% CI = 5.1 to 5.5) targeted biopsy cores were obtained from each patient. Targeted biopsy detected 461 cases of prostate cancer, of which 173 (37.5%) were high grade (Gleason score ≥ 4 + 3), while standard biopsy detected 469 cases of prostate cancer, of which 122 (26.5%) were high grade. The percentage of biopsy cores positive for prostate cancer, irrespective of grade, was statistically significantly higher for targeted than for standard biopsies (27.9% vs 13.5%, respectively, P < .001), with 11.5 targeted cores vs 26.2 standard cores utilized per diagnosis of prostate cancer. For detection of high-grade cancer, 30.7 targeted vs 100.8 standard cores were utilized per diagnosis.

CONCLUSION

In men with MR-visible prostate lesions, targeted biopsy is more efficient than standard biopsy, diagnosing a similar number of cancer cases and more high-grade cases while sampling 56.1% fewer biopsy cores.

Tissue Effects in a Randomized Controlled Trial of Short-term Finasteride in Early Prostate Cancer

BACKGROUND

In the Prostate Cancer Prevention Trial, finasteride selectively suppressed low-grade prostate cancer and significantly reduced the incidence of prostate cancer in men treated with finasteride compared with placebo. However, an apparent increase in high-grade disease was also observed among men randomized to finasteride. We aimed to determine why and hypothesized that there is a grade-dependent response to finasteride.

METHODS

From 2007 to 2012, we randomized dynamically by intranet-accessible software 183 men with localized prostate cancer to receive 5mg finasteride or placebo daily in a double-blind study during the 4-6weeks preceding prostatectomy. As the primary end point, the expression of a predefined molecular signature (ERβ, UBE2C, SRD5A2, and VEGF) differentiating high- and low-grade tumors in Gleason grade (GG) 3 areas of finasteride-exposed tumors from those in GG3 areas of placebo-exposed tumors, adjusted for Gleason score (GS) at prostatectomy, was compared. We also determined androgen receptor (AR) levels, Ki-67, and cleaved caspase 3 to evaluate the effects of finasteride on the expression of its downstream target, cell proliferation, and apoptosis, respectively. The expression of these markers was also compared across grades between and within treatment groups. Logistic regression was used to assess the expression of markers.

FINDINGS

We found that the predetermined molecular signature did not distinguish GG3 from GG4 areas in the placebo group. However, AR expression was significantly lower in the GG4 areas of the finasteride group than in those of the placebo group. Within the finasteride group, AR expression was also lower in GG4 than in GG3 areas, but not significantly. Expression of cleaved caspase 3 was significantly increased in both GG3 and GG4 areas in the finasteride group compared to the placebo group, although it was lower in GG4 than in GG3 areas in both groups.

INTERPRETATION

We showed that finasteride's effect on apoptosis and AR expression is tumor grade dependent after short-term intervention. This may explain finasteride's selective suppression of low-grade tumors observed in the PCPT.

Prospective Study Evaluating Na18F PET/CT in Predicting Clinical Outcomes and Survival in Advanced Prostate Cancer

This prospective pilot study evaluated the ability of Na(18)F PET/CT to detect and monitor bone metastases over time and its correlation with clinical outcomes and survival in advanced prostate cancer.

METHODS

Sixty prostate cancer patients, including 30 with and 30 without known bone metastases by conventional imaging, underwent Na(18)F PET/CT at baseline, 6 mo, and 12 mo. Positive lesions were verified on follow-up scans. Changes in SUVs and lesion number were correlated with prostate-specific antigen change, clinical impression, and overall survival.

RESULTS

Significant associations included the following: SUV and prostate-specific antigen percentage change at 6 mo (P = 0.014) and 12 mo (P = 0.0005); SUV maximal percentage change from baseline and clinical impression at 6 mo (P = 0.0147) and 6-12 mo (P = 0.0053); SUV change at 6 mo and overall survival (P = 0.018); number of lesions on Na(18)F PET/CT and clinical impression at baseline (P < 0.0001), 6 mo (P = 0.0078), and 12 mo (P = 0.0029); and number of lesions on Na(18)F PET/CT per patient at baseline and overall survival (P = 0.017). In an exploratory analysis, paired (99m)Tc-methylene diphosphonate bone scans ((99m)Tc-BS) were available for 35 patients at baseline, 19 at 6 mo, and 14 at 12 mo (68 scans). Malignant lesions on Na(18)F PET/CT (n = 57) were classified on (99m)Tc-BS as malignant 65% of the time, indeterminate 25% of the time, and negative 10% of the time. Additionally, 69% of paired scans showed more lesions on Na(18)F PET/CT than on (99m)Tc-BS.

CONCLUSION

The baseline number of malignant lesions and changes in SUV on follow-up Na(18)F PET/CT significantly correlate with clinical impression and overall survival. Na(18)F PET/CT detects more bone metastases earlier than (99m)Tc-BS and enhances detection of new bone disease in high-risk patients.

Comparison of survival of African-American (AA) patients (pts) in docetaxel (D)-based combination therapies in metastatic castrate-resistant prostate cancer (mCRPC)

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Background: AA pts experience greater prostate cancer (PC) incidence and mortality compared to Caucasian (C) pts but are underrepresented in clinical trials (CTs). Greater representation of AAs is required to explore differences in clinical benefit in advanced disease where recent data has reaffirmed the role of D. Methods: In a retrospective analysis, baseline characteristics, Gleason score (GS), ECOG PS, number of cycles (cys), maximum prostate-specific antigen (PSA) declines, radiographic responses, overall survival (OS) and progression-free survival (PFS) were captured in 2 recent D based CTs. Results: Of 136 pts, 28 (21%) self-identified as Black or AA. Median age of AA pts is 66 (50-78 yrs). Median GS is 8 (5-10). Median ECOG PS is 1 (0-2). 15 pts have bone and soft tissue disease; 13 pts have bone only disease. Median number of cys is 28.5 (1-63). Of 27 evaluable pts, 26 had PSA declines (-26 to -99%). Radiographic responses include 11 (39%) partial responses and 16 (57%) pts with stable disease. Median OS for AAs is 29.0 months (mos) (95% CI: 20.9-34.7 mos); median PFS is 21.5 mos (95% CI: 13.7-28.9 mos). Median OS for all non-AA pts is 24.8 mos (95% CI: 21.8-29.5 mos); median PFS is 16.1 mos (95% CI: 14.1-20.1 mos). The VEGF-634G > C SNP, associated with a more aggressive phenotype of PC, was evaluated in 54 pts. No evidence was found that genotype frequency varies between C and AA pts. Conclusions: In this analysis, AA pts did not have inferior OS (29 mos) or PFS (21.5 mos) outcomes compared to non-AA pts (24.8, 16.1 mos). Further analysis from larger studies is required to determine differential benefits of D for AA pts compared to non-AA pts. Clinical trial information: NCT00089609, NCT00942578.

Inflammation in Benign Prostate Tissue and Prostate Cancer in the Finasteride Arm of the Prostate Cancer Prevention Trial

BACKGROUND

A previous analysis of the placebo arm of the Prostate Cancer Prevention Trial (PCPT) reported 82% overall prevalence of intraprostatic inflammation and identified a link between inflammation and higher-grade prostate cancer and serum PSA. Here, we studied these associations in the PCPT finasteride arm.

METHODS

Prostate cancer cases (N = 197) detected either on a clinically indicated biopsy or on protocol-directed end-of-study biopsy, and frequency-matched controls (N = 248) with no cancer on an end-of-study biopsy were sampled from the finasteride arm. Inflammation in benign prostate tissue was visually assessed using digital images of hematoxylin and eosin-stained sections. Logistic regression was used for statistical analysis.

RESULTS

In the finasteride arm, 91.6% of prostate cancer cases and 92.4% of controls had at least one biopsy core with inflammation in benign areas (P < 0.001 for difference compared with placebo arm). Overall, the odds of prostate cancer did not differ by prevalence [OR, 0.90; 95% confidence interval (CI), 0.44-1.84] or extent (P trend = 0.68) of inflammation. Inflammation was not associated with higher-grade disease (prevalence: OR, 1.07; 95% CI, 0.43-2.69). Furthermore, mean PSA concentration did not differ by the prevalence or extent of inflammation in either cases or controls.

CONCLUSION

The prevalence of intraprostatic inflammation was higher in the finasteride than placebo arm of the PCPT, with no association with higher-grade prostate cancer.

IMPACT

Finasteride may attenuate the association between inflammation and higher-grade prostate cancer. Moreover, the missing link between intraprostatic inflammation and PSA suggests that finasteride may reduce inflammation-associated PSA elevation.

Randomized, Placebo-Controlled Trial of Green Tea Catechins for Prostate Cancer Prevention

Preclinical, epidemiologic, and prior clinical trial data suggest that green tea catechins (GTC) may reduce prostate cancer risk. We conducted a placebo-controlled, randomized clinical trial of Polyphenon E (PolyE), a proprietary mixture of GTCs, containing 400 mg (-)-epigallocatechin-3-gallate (EGCG) per day, in 97 men with high-grade prostatic intraepithelial neoplasia (HGPIN) and/or atypical small acinar proliferation (ASAP). The primary study endpoint was a comparison of the cumulative one-year prostate cancer rates on the two study arms. No differences in the number of prostate cancer cases were observed: 5 of 49 (PolyE) versus 9 of 48 (placebo), P = 0.25. A secondary endpoint comparing the cumulative rate of prostate cancer plus ASAP among men with HGPIN without ASAP at baseline, revealed a decrease in this composite endpoint: 3 of 26 (PolyE) versus 10 of 25 (placebo), P < 0.024. This finding was driven by a decrease in ASAP diagnoses on the Poly E (0/26) compared with the placebo arm (5/25). A decrease in serum prostate-specific antigen (PSA) was observed on the PolyE arm [-0.87 ng/mL; 95% confidence intervals (CI), -1.66 to -0.09]. Adverse events related to the study agent did not significantly differ between the two study groups. Daily intake of a standardized, decaffeinated catechin mixture containing 400 mg EGCG per day for 1 year accumulated in plasma and was well tolerated but did not reduce the likelihood of prostate cancer in men with baseline HGPIN or ASAP.

Variation in genes involved in the immune response and prostate cancer risk in the placebo arm of the Prostate Cancer Prevention Trial

BACKGROUND

We previously found that inflammation in benign prostate tissue is associated with an increased odds of prostate cancer, especially higher-grade disease. Since part of this link may be due to genetics, we evaluated the association between single nucleotide polymorphisms (SNPs) in immune response genes and prostate cancer in the placebo arm of the Prostate Cancer Prevention Trial.

METHODS

We genotyped 16 candidate SNPs in IL1β, IL2, IL4, IL6, IL8, IL10, IL12(p40), IFNG, MSR1, RNASEL, TLR4, and TNFA and seven tagSNPs in IL10 in 881 prostate cancer cases and 848 controls negative for cancer on an end-of-study biopsy. Cases and controls were non-Hispanic white and frequency matched on age and family history. We classified cases as lower (Gleason sum <7; N = 674) and higher (7-10; N = 172) grade, and used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusting for age and family history.

RESULTS

The minor allele (C) of rs3212227 in IL12(p40) was associated with an increased risk of total (log additive: OR = 1.30, 95%CI 1.10-1.53; P-trend = 0.0017) and lower-grade (OR = 1.36, 95%CI 1.15-1.62; P-trend = 0.0004) prostate cancer. The minor allele (A) of rs4073 in IL8 was possibly associated with a decreased risk of higher-grade (OR = 0.81, 95%CI 0.64-1.02; P-trend = 0.07), but not total disease. None of the other candidates was associated with risk. The minor alleles of IL10 tagSNPs rs1800890 (A; OR = 0.87, 95%CI: 0.75-0.99; P-trend = 0.04) and rs3021094 (C; OR = 1.31, 95%CI 1.03-1.66, P-trend = 0.03) were associated with risk; the latter also with lower- (P-trend = 0.04) and possibly higher- (P-trend = 0.06) grade disease. These patterns were similar among men with PSA <2 ng/ml at biopsy.

CONCLUSION

Variation in some immune response genes may be associated with prostate cancer risk. These associations were not fully explained by PSA-associated detection bias. Our findings generally support the role of inflammation in the etiology of prostate cancer.

Serum Retinol and Carotenoid Concentrations and Prostate Cancer Risk: Results from the Prostate Cancer Prevention Trial

BACKGROUND

Findings from epidemiologic studies examining associations of serum retinol and carotenoids with prostate cancer risk have been inconsistent. This case-control study nested in the Prostate Cancer Prevention Trial evaluated associations of serum retinol and carotenoids with total, low-, and high-grade prostate cancer risk in a highly screened study population.

METHODS

We used logistic regression adjusting for age, family history of prostate cancer, race, body mass index, and serum cholesterol to estimate ORs and 95% confidence intervals (CI) of prostate cancer by quartiles of serum retinol and carotenoids, separately in the placebo (975 cases/1,009 frequency-matched controls) and finasteride (708 cases/743 frequency-matched controls) arms of the trial.

RESULTS

Serum retinol concentrations were associated with increased risk of total prostate cancer [OR (95% CI) comparing the highest quartile of serum retinol with the lowest: 1.30 (1.00-1.68)] and high-grade prostate cancer [OR (95% CI), 1.74 (1.14-2.68)] in the placebo arm of the trial only. Also in the placebo arm, there was a moderate positive association of α-carotene with risk of total prostate cancer [OR (95% CI), 1.32 (1.01-1.73)]. None of the other carotenoids was associated with prostate cancer risk in the placebo arm. No associations were observed for retinol and carotenoids in the finasteride arm.

CONCLUSION

In the placebo arm of this prospective study, high serum retinol and α-carotene concentrations were associated with increased risk of total and high-grade prostate cancers.

IMPACT

Men with higher levels of serum retinol and α-carotene may be at increased risk for prostate cancer.