Unit Nonresponse in a Population-Based Study of Prostate Cancer

Low unit response rates can increase bias and compromise study validity. Response rates have continued to fall over the past decade despite all efforts to increase participation. Many factors have been linked to reduced response, yet relatively few studies have employed multivariate approaches to identify characteristics that differentiate respondents from nonrespondents since it is hard to collect information on the latter. We aimed to assess factors contributing to enrollment of prostate cancer (PCa) patients. We combined data from the North Carolina-Louisiana (LA) PCa Project's LA cohort, with additional sources such as US census tract and LA tumor registry data. We included specific analyses focusing on blacks, a group often identified as hard to enroll in health-related research. The ability to study the effect of Hurricane Katrina, which occurred amidst enrollment, as a potential determinant of nonresponse makes our study unique. Older age (≥ 70) for blacks (OR 0.65) and study phase with respect to Hurricane Katrina for both races (OR 0.59 for blacks, OR 0.48 for whites) were significant predictors of participation with lower odds. Neighborhood poverty for whites (OR 1.53) also was a significant predictor of participation, but with higher odds. Among blacks, residence in Orleans parish was associated with lower odds of participation (OR 0.33) before Katrina. The opposite occurred in whites, with lower odds (OR 0.43) after Katrina. Our results overall underscore the importance of tailoring enrollment approaches to specific target population characteristics to confront the challenges posed by nonresponse. Our results also show that recruitment-related factors may change when outside forces bring major alterations to a population's environment and demographics.

Prostate Cancer, Version 1.2016

The NCCN Guidelines for Prostate Cancer address staging and risk assessment after an initial diagnosis of prostate cancer and management options for localized, regional, and metastatic disease. Recommendations for disease monitoring, treatment of recurrent disease, and systemic therapy for metastatic castration-recurrent prostate cancer also are included. This article summarizes the NCCN Prostate Cancer Panel's most significant discussions for the 2016 update of the guidelines, which include refinement of risk stratification methods and new options for the treatment of men with high-risk and very-high-risk disease and progressive castration-naïve disease.

Carotenoid intake and adipose tissue carotenoid levels in relation to prostate cancer aggressiveness among African-American and European-American men in the North Carolina-Louisiana prostate cancer project (PCaP)

BACKGROUND

Associations between carotenoid intake and prostate cancer (CaP) incidence have varied across studies. This may result from combining indolent with aggressive disease in most studies. This study examined whether carotenoid intake and adipose tissue carotenoid levels were inversely associated with CaP aggressiveness.

METHODS

Data on African-American (AA, n = 1,023) and European-American (EA, n = 1,079) men with incident CaP from North Carolina and Louisiana were analyzed. Dietary carotenoid intake was assessed using a detailed-food frequency questionnaire (FFQ), and abdominal adipose tissue samples were analyzed for carotenoid concentrations using high-performance liquid chromatography. Multivariable logistic regression was used in race-stratified analyses to calculate odds ratios (ORs) and 95% confidence intervals (95%CI) comparing high aggressive CaP with low/intermediate aggressive CaP.

RESULTS

Carotenoid intake differed significantly between AAs and EAs, which included higher intake of lycopene among EAs and higher β-cryptoxanthin intake among AAs. Comparing the highest and lowest tertiles, dietary lycopene was associated inversely with high aggressive CaP among EAs (OR = 0.55, 95%CI: 0.34-0.89, Ptrend  = 0.02), while an inverse association was observed between dietary β-cryptoxanthin intake and high aggressive CaP among AAs (OR = 0.56, 95%CI: 0.36-0.87, Ptrend  = 0.01). Adipose tissue α-carotene and lycopene (cis + trans) concentrations were higher among EAs than AAs, and marginally significant inverse linear trends were observed for adipose α-carotene (Ptrend  = 0.07) and lycopene (Ptrend  = 0.11), and CaP aggressiveness among EAs only.

CONCLUSIONS

These results suggest that diets high in lycopene and β-cryptoxanthin may protect against aggressive CaP among EAs and AAs, respectively. Differences in dietary behaviors may explain the observed racial differences in associations. Prostate 76:1053-1066, 2016. © 2016 Wiley Periodicals, Inc.

Characterization of fibroblast-free CWR-R1ca castration-recurrent prostate cancer cell line

BACKGROUND

The previously established CWR-R1 cell line has been used as an in vitro model representing castration-recurrent prostate cancer. Microscopic observation of subconfluent cells demonstrated two distinct cellular morphologies: polygonal closely aggregated epithelial cells surrounded by bipolar fibroblastic cells with long processes. This study sought to establish and characterize a fibroblast-free derivative of the CWR-R1 cell line.

METHODS

The CWR-R1ca cell line was established from CWR-R1 cells by removing fibroblasts using multiple cycles of short-term trypsinization, cloning, and pooling single-cell colonies. Authentication of fibroblast-free CWR-R1ca cells was demonstrated by analyzing the expression of cytodifferentiation and prostate-associated markers, DNA and cytogenetic profiling, and growth pattern in the absence or presence of androgen.

RESULTS

CWR-R1ca is an androgen-sensitive cell line that expresses the androgen receptor (AR) and its splice variant 7 and the luminal epithelia markers, CK-8, CK-18, and c-Met. CWR-R1fb fibroblasts isolated from CWR-R1 cells express AR, hepatocyte growth factor-α, and mouse β-actin but not AR-V7 or epithelial markers. Cytogenetic analysis of CWR-R1ca cells revealed a hyperdiploid male with numerical gains in chromosomes 1, 7, 8, 10, 11, and 12, deletion of one chromosome 2 allele, structural abnormalities that include der(1)t(1:4), der(4)t(2:4), der(10)t(4:10), and an unbalanced reciprocal translocation between chromosome 6 and 14. DNA-profiling revealed that CWR-R1ca cells had significant short-tandem repeat marker homology with CWR22Pc and CWR22Rv1 cell lines, which indicated lineage derivation from CWR22 prostate cancer xenografts. CWR-R1ca cells were responsive to the growth stimulatory effects of dihydrotestosterone (DHT) in the femtomolar range.

CONCLUSION

This study establishes CWR-R1ca cells as a fibroblast-free derivative of the castration-recurrent CWR-R1 cell line. Prostate 76:1067-1077, 2016. © 2016 Wiley Periodicals, Inc.

GRM1 is An Androgen-Regulated Gene and its Expression Correlates with Prostate Cancer Progression in Pre-Clinical Models

PURPOSE

We recently demonstrated that glutamate receptor GRM1 was expressed at high levels in castration-resistant prostate cancer (CR-PCa) tissues and cells. Herein, we determined the relationship between GRM1 and AR, PSA, and tumor growth, remission, and recurrence in preclinical PCa models. The effect of alterations in GRM1 expression was also investigated on PCa cell growth, migration and invasion.

EXPERIMENTAL DESIGN

We used quantitative gene expression and immunohistochemistry to define the temporal association between GRM1 expression and AR, PSA, and tumor growth during CR progression in CWR22 (n = 59) and LuCaP 35 (n = 12) PCa xenografts. The effect of alterations in GRM1 expression levels on growth, migration, and invasion was investigated in GRM1-overexpressed or -silenced PCa cell lines. The effect of DHT on GRM1 expression was determined in the presence or absence of the antiandrogen bicalutamide.

RESULTS

We found that GRM1 transcript and tissue expression directly correlated with growth and AR and PSA expression in hormone-sensitive (HS), castrated, and CR tumor xenografts. GRM1 overexpression or silencing directly correlated with PCa cell proliferation, migration, and invasion. DHT increased GRM1 expression via an AR-dependent manner in HS- and CR-PCa cell lines.

CONCLUSIONS

This is a first report of GRM1 as an androgen and AR-target gene. GRM1 expression directly correlated with tumor growth, regression, and recurrence and may contribute to CR-progression of PCa in preclinical models. Further studies are needed to define the utility of GRM1 as a druggable target or biomarker for PCa.

Intratumoral and Intertumoral Genomic Heterogeneity of Multifocal Localized Prostate Cancer Impacts Molecular Classifications and Genomic Prognosticators

BACKGROUND

Next-generation sequencing is revealing genomic heterogeneity in localized prostate cancer (CaP). Incomplete sampling of CaP multiclonality has limited the implications for molecular subtyping, stratification, and systemic treatment.

OBJECTIVE

To determine the impact of genomic and transcriptomic diversity within and among intraprostatic CaP foci on CaP molecular taxonomy, predictors of progression, and actionable therapeutic targets.

DESIGN, SETTING, AND PARTICIPANTS

Four consecutive patients with clinically localized National Comprehensive Cancer Network intermediate- or high-risk CaP who did not receive neoadjuvant therapy underwent radical prostatectomy at Roswell Park Cancer Institute in June-July 2014. Presurgical information on CaP content and a customized tissue procurement procedure were used to isolate nonmicroscopic and noncontiguous CaP foci in radical prostatectomy specimens. Three cores were obtained from the index lesion and one core from smaller lesions. RNA and DNA were extracted simultaneously from 26 cores with ≥90% CaP content and analyzed using whole-exome sequencing, single-nucleotide polymorphism arrays, and RNA sequencing.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Somatic mutations, copy number alternations, gene expression, gene fusions, and phylogeny were defined. The impact of genomic alterations on CaP molecular classification, gene sets measured in Oncotype DX, Prolaris, and Decipher assays, and androgen receptor activity among CaP cores was determined.

RESULTS AND LIMITATIONS

There was considerable variability in genomic alterations among CaP cores, and between RNA- and DNA-based platforms. Heterogeneity was found in molecular grouping of individual CaP foci and the activity of gene sets underlying the assays for risk stratification and androgen receptor activity, and was validated in independent genomic data sets. Determination of the implications for clinical decision-making requires follow-up studies.

CONCLUSIONS

Genomic make-up varies widely among CaP foci, so care should be taken when making treatment decisions based on a single biopsy or index lesions.

PATIENT SUMMARY

We examined the molecular composition of individual cancers in a patient's prostate. We found a lot of genetic diversity among these cancers, and concluded that information from a single cancer biopsy is not sufficient to guide treatment decisions.

Abstract 1760: Saturated fat intake and prostate cancer aggressiveness: Results from the population-based North Carolina-Louisiana prostate cancer project

Introduction: Epidemiologic data support a positive association between hypercholesterolemia and aggressive prostate cancer, and an inverse association between statin use and aggressive prostate cancer. Saturated fat intake is an important dietary determinant of serum cholesterol levels. However, epidemiologic evidence supporting a role for saturated fat in prostate cancer aggressiveness is mixed. We hypothesized that high saturated fat intake would be associated with increased prostate cancer aggressiveness, and that this association would be modified by statin use.

Methods: Of 1,854 prostate cancer cases in the North Carolina-Louisiana Prostate Cancer Project (PCaP), 321 (17%) were classified as high aggressive based on clinical criteria. Saturated fat intake was adjusted for total fat intake using the residual method, and categorized into tertiles based on the distribution among all research subjects. Using low and intermediate aggressive cases as the reference group, logistic regression was used to examine the association between tertiles of saturated fat intake and prostate cancer aggressiveness, overall and stratified by race and by statin use. In addition to demographic and screening variables, energy-adjusted total fat intake and energy intake were included as covariates in our models. In secondary analysis, we examined associations for total fat, monounsaturated and polyunsaturated fatty acids (MUFA and PUFA, respectively), trans fat, and cholesterol intake.

Results: High saturated fat intake was associated with an elevated odds ratio (OR) for aggressive prostate cancer (ORupper tertile (T3) vs. lower (T1) 1.44; 95% CI 1.06-1.96; p-trend = 0.020). The magnitude of this association was weaker in statin users (ORT3 vs. T1 1.10; 95% CI 0.63-1.91; p-trend = 0.790) compared to men not using statins (ORT3 vs. T1 1.63; 95% CI 1.11-2.37; p-trend = 0.015). There was a suggestion of a positive association between high cholesterol intake and aggressive prostate cancer among all men (ORT3 vs. T1 1.28; 95% CI 0.94-1.75; p-trend = 0.074), and this association was more pronounced in European Americans (ORT3 vs. T1 1.82; 95% CI 1.15-2.88; p-trend = 0.012). Elevated PUFA intake was inversely associated with prostate cancer aggressiveness (ORT3 vs. T1 0.66; 95% CI 0.48-0.90; p-trend = 0.009), with similar effect estimates in both races. There were no associations between trans fat or MUFA and prostate cancer aggressiveness.

Conclusions: Elevated intake of saturated fat was positively associated, while high intake of PUFA was inversely associated, with aggressive prostate cancer. Weaker associations between saturated fat and prostate cancer aggressiveness in statin users suggest that the impact of saturated fat on serum cholesterol levels may be one potential mechanism by which saturated fat impacts prostate cancer aggressiveness.

Citation Format: Emma H. Allott, Lenore Arab, L. Joseph Su, Laura Farnan, Elizabeth T.H. Fontham, James L. Mohler, Jeannette T. Bensen, Susan E. Steck. Saturated fat intake and prostate cancer aggressiveness: Results from the population-based North Carolina-Louisiana prostate cancer project. [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 1760.

Clinical significance of prospectively assigned Gleason tertiary pattern 4 in contemporary Gleason score 3+3=6 prostate cancer

OBJECTIVE

To determine the oncologic impact of prospectively assigned tertiary pattern 4 in contemporary Gleason score (GS) 3 + 3 = 6 radical prostatectomy (RP) specimens.

PATIENTS AND METHODS

Oncologic outcomes were retrospectively reviewed for 720 consecutive patients from a single National Comprehensive Cancer Network (NCCN) center with at least 6 months follow-up after RP for GS3 + 3 = 6 (GS6, N = 222), GS6 with tertiary pattern 4 (GS6t4, N = 62), or GS3 + 4 = 7 (N = 436) prostate cancer, as prospectively graded since 2006 using the 2005 International Society of Urologic Pathologists criteria. Preoperative NCCN risk category, RP pathology, progression-free survival (PFS) and metastasis-free survival (MFS) were compared among the GS6, GS6t4, and GS3 + 4 = 7 groups using χ(2) , Kaplan-Meier, and log-rank analyses.

RESULTS

The incidence of low NCCN preoperative risk classification for GS6t4 patients (63%) was less than that for GS6 patients (77%) while greater than that for GS3 + 4 = 7 patients (30%, P < 0.001). GS6t4 patients had RP pathologic features which were intermediate in risk between that of GS6 and GS3 + 4 = 7 based on extraprostatic extension (27% vs. 6% vs. 31%, respectively, P < 0.001) and mean percentage of prostate gland involvement (13% vs. 10% vs. 16%, respectively, P < 0.001). With a mean overall follow-up of 42 months, PFS for GS6t4 patients (5-year 85%) was intermediate between that of GS6 (5-year 93%) and GS3 + 4 = 7 (5-year 76%) patients (P < 0.001). The 5-year MFS rate was 100% for GS6 and GS6t4 patients compared to 97% for GS3 + 4 = 7 patients (P = 0.07).

CONCLUSIONS

This study provides the longest follow-up to date for RP patients with prospectively assigned GS6t4 and supports a risk for adverse RP pathology and postoperative disease progression that is intermediate between GS6 and GS3 + 4 = 7. Whether a tertiary pattern 4 in GS6 disease increases the risk of metastasis is uncertain and requires longer term study. Given favorable oncologic outcomes, less stringent postoperative surveillance for both GS6 and GS6t4 patients may be warranted.

Evolving Use of Androgen Deprivation Therapy in Prostate Cancer Management

Since its introduction more than 70 years ago, the use of androgen deprivation therapy (ADT) for prostate cancer has evolved to become part of a multimodal management approach. In this presentation from the NCCN 21st Annual Conference, James L. Mohler, MD, reviewed data that inform these strategies and gave his bottom-line recommendations on issues such as ADT plus radiotherapy, continuous versus intermittent ADT, ADT for positive nodes, and ADT plus docetaxel. He suggested that ADT plus radiation therapy should be used in patients at high risk, intermittent ADT is more appropriate for most patients than continuous ADT, and docetaxel should be given with ADT for high-volume metastatic disease.

Antineoplastic Isoflavonoids Derived from Intermediate ortho-Quinone Methides Generated from Mannich Bases

The regioselective condensations of various 7-hydroxyisoflavonoids with bis(N,N-dimethylamino)methane in a Mannich reaction provided C-8 N,N-dimethylaminomethyl-substituted isoflavonoids in good yield. Similar condensations of 7-hydroxy-8-methylisoflavonoids led to the C-6-substituted analogs. Thermal eliminations of dimethylamine from these C-6 or C-8 N,N-dimethylaminomethyl-substituted isoflavonoids generated ortho-quinone methide intermediates within isoflavonoid frameworks for the first time. Despite other potential competing outcomes, these ortho-quinone methide intermediates trapped dienophiles including 2,3-dihydrofuran, 3,4-dihydro-2H-pyran, 3-(N,N-dimethylamino)-5,5-dimethyl-2-cyclohexen-1-one, 1-morpholinocyclopentene, and 1-morpholinocyclohexene to give various inverse electron-demand Diels-Alder adducts. Several adducts derived from 8-N,N-dimethylaminomethyl-substituted isoflavonoids displayed good activity in the 1-10 μm concentration range in an in vitro proliferation assay using the PC-3 prostate cancer cell line.

Regulators of Androgen Action Resource: a one-stop shop for the comprehensive study of androgen receptor action

Androgen receptor (AR) is a ligand-activated transcription factor that is the main target for treatment of non-organ-confined prostate cancer (CaP). Failure of life-prolonging AR-targeting androgen deprivation therapy is due to flexibility in steroidogenic pathways that control intracrine androgen levels and variability in the AR transcriptional output. Androgen biosynthesis enzymes, androgen transporters and AR-associated coregulators are attractive novel CaP treatment targets. These proteins, however, are characterized by multiple transcript variants and isoforms, are subject to genomic alterations, and are differentially expressed among CaPs. Determining their therapeutic potential requires evaluation of extensive, diverse datasets that are dispersed over multiple databases, websites and literature reports. Mining and integrating these datasets are cumbersome, time-consuming tasks and provide only snapshots of relevant information. To overcome this impediment to effective, efficient study of AR and potential drug targets, we developed the Regulators of Androgen Action Resource (RAAR), a non-redundant, curated and user-friendly searchable web interface. RAAR centralizes information on gene function, clinical relevance, and resources for 55 genes that encode proteins involved in biosynthesis, metabolism and transport of androgens and for 274 AR-associated coregulator genes. Data in RAAR are organized in two levels: (i) Information pertaining to production of androgens is contained in a ‘pre-receptor level’ database, and coregulator gene information is provided in a ‘post-receptor level’ database, and (ii) an ‘other resources’ database contains links to additional databases that are complementary to and useful to pursue further the information provided in RAAR. For each of its 329 entries, RAAR provides access to more than 20 well-curated publicly available databases, and thus, access to thousands of data points. Hyperlinks provide direct access to gene-specific entries in the respective database(s). RAAR is a novel, freely available resource that provides fast, reliable and easy access to integrated information that is needed to develop alternative CaP therapies.

Database URL: http://www.lerner.ccf.org/cancerbio/heemers/RAAR/search/

NCCN Roundtable:Value-Based Decision-Making at the Bedside

As part of the NCCN 20th Annual Conference: Advancing the Standard of Cancer Care, a distinguished and diverse group of experts on value-based decision-making in oncology discussed guidelines and pathways and how their use has impacted bedside evidence-based decision-making for both physicians and patients. Moderated by Clifford Goodman, PhD, the roundtable also reflected on the criteria used to assess shared decision-making and the relationship between outcomes and cost when determining value.

Dietary Total Antioxidant Capacity is Inversely Associated with Prostate Cancer Aggressiveness in a Population-Based Study

The purpose of this study was to determine the relationship between total antioxidant capacity (TAC) from diet and supplements and prostate cancer aggressiveness among 855 African Americans (AA) and 945 European Americans (EA) in the North Carolina-Louisiana Prostate Cancer Project (PCaP). Cases were classified as either high aggressive, low aggressive, or intermediate aggressive. TAC was calculated from the vitamin C equivalent antioxidant capacity of 42 antioxidants measured via food frequency questionnaire. EA reported greater dietary TAC from diet and supplements combined (P < 0.0001). In both minimally and fully adjusted logistic regression models, TAC from diet and supplements combined was associated with a reduced odds of high aggressive prostate cancer in all men, AA and EA: odds ratios for highest vs. lowest level (>1500 vs. <500 mg vitamin C equivalent/day): 0.31 [95% confidence interval (CI): 0.15, 0.67; P-trend < 0.01], 0.28 (95% CI: 0.08, 0.96; P-trend < 0.001), and 0.36 (95% CI: 0.15, 0.86; P-trend = 0.58), respectively. These associations did not appear to differ between AA and EA. These data suggest that greater intake of antioxidants is associated with less aggressive prostate cancer. Additional research is needed to confirm these results and determine the underlying mechanisms.

Impact of devascularization and tissue procurement on cell number and RNA integrity in prostatectomy tissue

BACKGROUND

Minimizing the time between tissue devascularization in robot-assisted laparoscopic radical prostatectomy (RALP) and tissue procurement should produce the highest quality tissue for research study. This study examines the relationship between intra-operative time and two indicators of tissue integrity: number of epithelial cells per gram of tissue and RNA integrity numbers (RINs). The study also compares the RIN values of tissue obtained intra-operatively by biopsy, before and after devascularization, to those from RALP specimen tissue, obtained through the routine research tissue procurement process.

METHODS

Prostate tissues from two series of patients were analyzed. In the first, tissue from 18 patients undergoing RALP was analyzed for number of epithelial cells per gram of tissue. In the second, RIN values of tissue from 46 patients involved in a clinical study were analyzed. RIN values were assessed from RALP specimen tissue as well as tissue removed intra-operatively by biopsy, before and after devascularization.

RESULTS

Time from RALP to tissue procurement was not significantly associated with number of epithelial cells per gram of tissue or with RIN values. RINs of biopsy tissue obtained intra-operatively before and after devascularization were similar. However, the RIN values of tissue from RALP specimens were significantly higher than those of biopsy tissue obtained either before or after devascularization.

CONCLUSIONS

Tissue quality, defined by number of epithelial cells or RIN values, was not affected by time between devascularization and procurement. Obtaining tissue from intra-operative biopsies, either before or after devascularization, is not necessary and actually produced lower RINs than found in tissue from RALP specimens, obtained through the routine research tissue procurement process.

Application of Mannich bases to the synthesis of hydroxymethylated isoflavonoids as potential antineoplastic agents

The regiospecific Mannich aminomethylation of 7-hydroxyisoflavonoids using bis(N,N-dimethylamino)methane afforded C-8 substituted N,N-dimethylaminomethyl adducts, and the regioselective aminomethylation of 5-hydroxy-7-methoxyisoflavonoids afforded predominantly the C-6 substituted N,N-dimethylaminomethyl adducts. Acetylation of these C-6 or C-8 Mannich bases with potassium acetate in acetic anhydride provided access to the corresponding acetoxymethyl derivatives that were subsequently converted to hydroxymethyl- and methoxymethyl-substituted 5-hydroxy- or 7-hydroxyisoflavonoids related to naturally occurring flavonoids. The C-8 acetoxymethyl, hydroxymethyl or methoxymethyl-substituted isoflavonoids possessed promising inhibitory potency in the low micromolar range in a prostate cancer PC-3 cell proliferation assay.

Dietary, supplement, and adipose tissue tocopherol levels in relation to prostate cancer aggressiveness among African and European Americans: The North Carolina-Louisiana Prostate Cancer Project (PCaP)

BACKGROUND

Controversies remain over the safety and efficacy of vitamin E (i.e., α-tocopherol) supplementation use for the prevention of prostate cancer (CaP); however, associations of different tocopherol forms and CaP aggressiveness have yet to be examined.

METHODS

This study examined whether food intake of tocopherols, vitamin E supplement use, and adipose tissue biomarkers of tocopherol were associated with CaP aggressiveness among African-American (AA, n = 1,023) and European-American (EA, n = 1,079) men diagnosed with incident CaP. Dietary tocopherols were estimated from a food frequency questionnaire, supplement use from questionnaire/inventory, and biomarkers from abdominal adipose samples measured using high-performance liquid chromatography. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were estimated from logistic regression comparing high-aggressive CaP to low/intermediate aggressive CaP, adjusting for covariates.

RESULTS

Dietary intakes of α-and δ-tocopherol were related inversely to CaP aggressiveness among EAs [OR (95%CI), highest versus lowest quartile: α-tocopherol, 0.34 (0.17-0.69), P(trend)  = 0.006; δ-tocopherol, 0.45 (0.21-0.95) P(trend)  = 0.007]. Inverse associations between dietary and supplemental α-tocopherol and CaP aggressiveness were observed among AAs, though these did not reach statistical significance [OR (95%CI), highest versus lowest quartile: dietary α-tocopherol, 0.58 (0.28-1.19), P(trend)  = 0.20; supplemental α-tocopherol, 0.64 (0.31-1.21) P(trend)  = 0.15]. No significant association was observed between adipose tocopherol levels and CaP aggressiveness [OR (95%CI), highest versus lowest quartiles of α-tocopherol for EAs 1.43 (0.66-3.11) and AAs 0.66 (0.27-1.62)].

CONCLUSIONS

The inverse associations observed between dietary sources of tocopherols and CaP aggressiveness suggests a beneficial role of food sources of these tocopherols in CaP aggressiveness.

Abstract 1881: Dietary, supplement, and adipose tissue tocopherol levels in relation to prostate cancer aggressiveness among African- and European-Americans

Background: Controversies remain over the safety and efficacy of vitamin E (α-tocopherol) supplement use for the prevention of prostate cancer (CaP); however, associations between different tocopherol forms and CaP aggressiveness have yet to be examined. This study examined whether food intake of tocopherols, vitamin E supplement use, and adipose tissue biomarkers of tocopherol were associated with CaP aggressiveness among African-American (AA) and European-American (EA) men with newly diagnosed CaP.

Methods: Associations between tocopherols from diet, vitamin E supplement use, and adipose tissue tocopherol levels and CaP aggressiveness were examined in a large population-based, case-only study of incident CaP among AA (n = 1,023) and EA (n = 1,079) research subjects enrolled in the North Carolina-Louisiana Prostate Cancer Project (PCaP). CaP aggressiveness was defined by a combination of clinical Gleason sum and stage and prostate-specific antigen (PSA) level at diagnosis as high aggressive (Gleason sum ≥8 or PSA &gt;20 ng/mL, or Gleason sum ≥ 7 and cancer stage T3-T4); low aggressive (Gleason sum &lt; 7 and stage T1-T2 and PSA&lt;10 ng/ml); or intermediate aggressive CaP (all others). Dietary tocopherol intake was estimated from a food frequency questionnaire, supplement use from questionnaire/inventory, and biomarkers from abdominal adipose samples measured using high-performance liquid chromatography. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) comparing high aggressive CaP to low/intermediate aggressive CaP.

Results: Higher dietary intakes of α- and δ-tocopherol were inversely and linearly associated with CaP aggressiveness among EAs [OR (95%CI), highest vs. lowest quartile: α-tocopherol 0.34 (0.17-0.69) Ptrend = 0.006; δ-tocopherol 0.45 (0.21-0.95) Ptrend = 0.007]. Dietary tocopherol levels were not associated with CaP aggressiveness among AAs. No significant associations were observed between supplemental vitamin E use and CaP aggressiveness among AAs or EAs. Mean adipose α-tocopherol concentrations were markedly higher in EAs (151.4 mcg/g) compared to AAs (86.6 mcg/g). No statistically significant associations between adipose α-tocopherol levels and high aggressive CaP were observed [OR (95%CI); highest versus lowest quartiles were for EAs 1.43 (0.66-3.11) and AAs 0.66 (0.27-1.62)].

Conclusions: These results add to the literature suggesting no obvious benefit from vitamin E supplement use in relation to CaP aggressiveness. Inverse associations between higher dietary sources of tocopherols and aggressive CaP among EAs suggest that diets high in tocopherols may contain additional protective components or may be a marker for an overall healthier lifestyle.

Citation Format: Samuel Antwi, Susan E. Steck, L. Joseph Su, James R. Hebert, Hongmei Zhang, Elizabeth T. H. Fontham, Jeannette T. Bensen, James L. Mohler, Lenore Arab. Dietary, supplement, and adipose tissue tocopherol levels in relation to prostate cancer aggressiveness among African- and European-Americans. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1881. doi:10.1158/1538-7445.AM2015-1881

Long-term oncologic outcomes following robot-assisted radical cystectomy: results from the International Robotic Cystectomy Consortium

BACKGROUND

Long-term oncologic data on patients undergoing robot-assisted radical cystectomy (RARC) are limited and based largely on single-institution series.

OBJECTIVE

Report survival outcomes of patients who underwent RARC ≥5 yr ago.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective review of the prospectively populated International Robotic Cystectomy Consortium multi-institutional database identified 743 patients with RARC performed ≥5 yr ago. Clinical, pathologic, and survival data at the latest follow-up were collected. Patients with palliative RARC were excluded. Final analysis was performed on 702 patients from 11 institutions in 6 countries.

INTERVENTION

RARC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Outcomes of interest, recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) were plotted using Kaplan-Meier survival curves. A Cox proportional hazards model was used to identify factors that predicted outcomes.

RESULTS AND LIMITATIONS

Pathologic organ-confined (OC) disease was found in 62% of patients. Soft tissue surgical margins (SMs) were positive in 8%. Median lymph node (LN) yield was 16, and 21% of patients had positive LNs. Median follow-up was 67 mo (interquartile range: 18-84 mo). Five-year RFS, CSS, and OS were 67%, 75%, and 50%, respectively. Non-OC disease and SMs were associated with poorer RFS, CSS, and OS on multivariable analysis. Age predicted poorer CSS and OS. Adjuvant chemotherapy and positive SMs were predictors of RFS (hazard ratio: 3.20 and 2.16; p<0.001 and p<0.005, respectively). Stratified survival curves demonstrated poorer outcomes for positive SM, LN, and non-OC disease. Retrospective interrogation and lack of contemporaneous comparison groups that underwent open radical cystectomy were major limitations.

CONCLUSIONS

The largest multi-institutional series to date reported long-term survival outcomes after RARC.

PATIENT SUMMARY

Patients who underwent robot-assisted radical cystectomy for bladder cancer have acceptable long-term survival.

Association between Plasma 25-Hydroxyvitamin D, Ancestry and Aggressive Prostate Cancer among African Americans and European Americans in PCaP

BACKGROUND

African Americans (AAs) have lower circulating 25-hydroxyvitamin D3 [25(OH)D3] concentrations and higher prostate cancer (CaP) aggressiveness than other racial/ethnic groups. The purpose of the current study was to examine the relationship between plasma 25(OH)D3, African ancestry and CaP aggressiveness among AAs and European Americans (EAs).

METHODS

Plasma 25(OH)D3 was measured using LC-MS/MS (Liquid Chromatography Tandem Mass Spectrometry) in 537 AA and 663 EA newly-diagnosed CaP patients from the North Carolina-Louisiana Prostate Cancer Project (PCaP) classified as having either 'high' or 'low' aggressive disease based on clinical stage, Gleason grade and prostate specific antigen at diagnosis. Mean plasma 25(OH)D3 concentrations were compared by proportion of African ancestry. Logistic regression was used to calculate multivariable adjusted odds ratios (OR) and 95% confidence intervals (95%CI) for high aggressive CaP by tertile of plasma 25(OH)D3.

RESULTS

AAs with highest percent African ancestry (>95%) had the lowest mean plasma 25(OH)D3 concentrations. Overall, plasma 25(OH)D3 was associated positively with aggressiveness among AA men, an association that was modified by calcium intake (ORT 3vs.T1: 2.23, 95%CI: 1.26-3.95 among men with low calcium intake, and ORT 3vs.T1: 0.19, 95%CI: 0.05-0.70 among men with high calcium intake). Among EAs, the point estimates of the ORs were <1.0 for the upper tertiles with CIs that included the null.

CONCLUSIONS

Among AAs, plasma 25(OH)D3 was associated positively with CaP aggressiveness among men with low calcium intake and inversely among men with high calcium intake. The clinical significance of circulating concentrations of 25(OH)D3 and interactions with calcium intake in the AA population warrants further study.

Association of fatty-acid synthase polymorphisms and expression with outcomes after radical prostatectomy

BACKGROUND

Fatty-acid synthase (FASN), selectively overexpressed in prostate cancer (PCa) cells, has been described as linked to the aggressiveness of PCa. Constitutional genetic variation of the FASN gene and the expression levels of FASN protein in cancer cells could thus be expected to predict outcome after radical prostatectomy (RP). This study evaluates the associations of malignant tissue status, neoadjuvant androgen deprivation therapy (NADT) and single-nucleotide polymorphisms (SNPs) of FASN with FASN protein expression in prostate tissue. The study then examines the associations of FASN SNPs and gene expression with three measures of post-prostatectomy outcome.

METHODS

Seven tagging FASN SNPs were genotyped in 659 European American men who underwent RP at Roswell Park Cancer Institute between 1993 and 2005. FASN protein expression was assessed using immunohistochemistry. The patients were followed for an average of 6.9 years (range: 0.1-20.6 years). Outcome was assessed using three end points: biochemical failure, treatment failure and development of distant metastatic PCa. Cox proportional hazards analyses were used to evaluate the associations of the tagging SNPs and FASN expression with these end points. Bivariate associations with outcomes were considered; the associations also were controlled for known aggressiveness indicators.

RESULTS

Overall, no SNPs were associated with any known aggressiveness indicators. FASN staining intensity was stronger in malignant than in benign tissue, and NADT was associated with decreased FASN staining in both benign and malignant tissue. The relationships of FASN SNPs and staining intensity with outcome were less clear. One SNP, rs4246444, showed a weak association with outcome. FASN staining intensity also showed a weak and seemingly contradictory relationship with outcome.

CONCLUSIONS

Additional study with longer follow-up and populations that include more metastatic patients is warranted.

Associations of prostate cancer risk variants with disease aggressiveness: results of the NCI-SPORE Genetics Working Group analysis of 18,343 cases

Genetic studies have identified single nucleotide polymorphisms (SNPs) associated with the risk of prostate cancer (PC). It remains unclear whether such genetic variants are associated with disease aggressiveness. The NCI-SPORE Genetics Working Group retrospectively collected clinicopathologic information and genotype data for 36 SNPs which at the time had been validated to be associated with PC risk from 25,674 cases with PC. Cases were grouped according to race, Gleason score (Gleason ≤ 6, 7, ≥ 8) and aggressiveness (non-aggressive, intermediate, and aggressive disease). Statistical analyses were used to compare the frequency of the SNPs between different disease cohorts. After adjusting for multiple testing, only PC-risk SNP rs2735839 (G) was significantly and inversely associated with aggressive (OR = 0.77; 95 % CI 0.69-0.87) and high-grade disease (OR = 0.77; 95 % CI 0.68-0.86) in European men. Similar associations with aggressive (OR = 0.72; 95 % CI 0.58-0.89) and high-grade disease (OR = 0.69; 95 % CI 0.54-0.87) were documented in African-American subjects. The G allele of rs2735839 was associated with disease aggressiveness even at low PSA levels (<4.0 ng/mL) in both European and African-American men. Our results provide further support that a PC-risk SNP rs2735839 near the KLK3 gene on chromosome 19q13 may be associated with aggressive and high-grade PC. Future prospectively designed, case-case GWAS are needed to identify additional SNPs associated with PC aggressiveness.