Castro, Ramiro

75 Background: We have previously shown that chronic baseline prostate inflammation in an otherwise benign biopsy was associated with lower risk of prostate cancer in repeat prostate biopsies and lower tumor volumes for those who are diagnosed with cancer. In the present study, we evaluated whether baseline acute or chronic prostate inflammation among men with initial negative biopsies for prostate cancer was associated with cancer grade at the 2-year repeat prostate biopsy. Methods: Retrospective analysis of 889 men 50-75 years-old with negative baseline prostate biopsy and positive 2-year repeat biopsy for prostate cancer in the REDUCE study. Acute and chronic prostate inflammation (coded as present or absent) and cancer grade were determined by central pathology. The association of inflammation in baseline biopsies with 2-year repeat biopsy cancer grade (low-grade: Gleason scores 2-6 vs. high-grade: Gleason scores 7-10) was evaluated with t test, chi-squared test and logistic regression controlling for age, race, body-mass index (BMI), digital rectal exam (DRE), prostate volume, baseline pre-study PSA and treatment (dutasteride or placebo). Results: Chronic, acute inflammation and both were detected in 533 (60%), 12 (1%) and 85 (10%) baseline biopsies, respectively. Presence of acute and chronic inflammations were significantly associated with each other (P < 0.001). Patients with chronic inflammation had significantly larger prostates (P < 0.001). Both types of inflammation were unrelated to race, BMI, PSA or DRE. At 2-year biopsy, a total of 621 (70%) tumors were low-grade and 268 (30%) tumors were high-grade. In both uni- and multivariable analyses, men with baseline chronic inflammation had significantly less high-grade tumors (univariable OR = 0.64, 95% CI = 0.47-0.87, P = 0.004; multivariable OR = 0.68, 95% CI = 0.50-0.93, P = 0.016) than those without baseline chronic inflammation. Baseline acute inflammation was not associated with tumor grade. Conclusions: Among men undergoing repeat prostate biopsy 2 years after a negative baseline biopsy who all had cancer on the follow-up biopsy, the presence baseline chronic inflammation was associated with lower prostate cancer grade.

6 Background: Study compliance is crucial when the study outcome is determined by an invasive procedure, such as prostate biopsy. To investigate predictors of compliance in study-mandated prostate biopsies, we analyzed demographic, clinical and reported lifestyle data from the REDUCE trial. Methods: We retrospectively identified 8,062 men from REDUCE with at least 2-years of follow-up, and used multivariable logistic regression to test the association between baseline demographic and clinical characteristics and undergoing the study-mandated prostate biopsy at 2 years. We then examined whether missing any of these data was associated with undergoing a biopsy. Results: In REDUCE, 20% of men did not undergo a 2-year biopsy.On multivariable analysis, non-North American region was predictive of 35-55% increased likelihood of undergoing a 2-year biopsy (p ≤ 0.001). Being enrolled at a center that enrolled >10 subjects (2nd and 3rd tertile) was associated with a 40-49% increased likelihood of undergoing a 2-year biopsy (p < 0.001). Missing one or more baseline variables was associated with a 25% decreased likelihood of undergoing a 2-year biopsy (OR = 0.75; p = 0.002). Conclusions: In REDUCE, men outside North America, those at higher volume centers, and those with complete baseline data were more likely to undergo study mandated 2-year biopsies. Given prostate biopsy is becoming increasingly utilized as an endpoint in trials that are often multi-national, regional differences in compliance should be considered when designing future trials. Likewise, efforts are needed to ensure compliance in low-volume centers or among subjects missing baseline data.

122 Background: We have previously shown baseline prostate atrophy (PA) was independently associated with lower prostate cancer (PC) risk. Beyond PC risk, for those who develop PC it is unclear whether PA is associated with smaller, less aggressive and/or less advanced tumors. Thus, we evaluated whether baseline PA and PA severity in men with initial negative biopsy for PC was associated with PC volume at the 2-year repeat prostate biopsy. Methods: Retrospective analysis of 763 men 50-75 years-old with negative baseline prostate biopsy and positive 2-year repeat biopsy for PC with complete data in the REDUCE study. Presence and severity of PA, and tumor volume were determined by central pathology. The association of PA at baseline biopsies with 2-year repeat biopsy cancer volume variables was evaluated with linear and Poisson regressions and controlling for age, race, body-mass index (BMI), digital rectal exam (DRE), prostate volume, baseline and pre-repeat biopsy prostate-specific antigen (PSA) and treatment arm. Results: PA was detected in 458 (60%) baseline biopsies and was considered mild in 398 (87%) and moderate in 60 (13%) cases. Patients with PA had significantly larger prostates and lower baseline and pre-repeat biopsy PSA (P < 0.01). PA was unrelated to race, BMI, DRE or treatment arm. At 2-year biopsy, men with baseline PA had significantly lower overall mean total tumor volume (2.04µL vs 3.02µL; P = 0.006), mean number of biopsy cores involved (1.79 vs 2.11; P = 0.001), mean percent of cores involved (17.9% vs 21.2%; P = 0.001), average core involvement (0.20µL vs 0.30µL; P = 0.001) and overall mean percent tumor involvement (1.64% vs 2.35%; P = 0.006) than those without PA. The results were virtually unchanged in multivariable analysis (all P < 0.05 except for overall percent tumor involvement where P = 0.061). In the analysis of PA severity, a biological gradient was observed where moderate PA was associated with greater reduction in tumor volume compared to mild PA (data not shown). Conclusions: In a cohort of men with 2-year repeat prostate biopsy positive for PC after a negative baseline biopsy, baseline PA was associated with lower PC volume. These results suggest PA may be associated with less aggressive PC.

116 Background: Prostateinflammation is linked with prostate cancer. However, whether prostate inflammation varies by race is unclear. Methods: We analyzed baseline acute and chronic prostate inflammation by race in REDUCE. REDUCE was a 4-year, multicenter, placebo-controlled study where all men received a single, negative prostate biopsy within 6 months prior to enrollment. Among 8,046 men who met the inclusion criteria, we included those with data on baseline biopsy prostate inflammation, acute/chronic or none, determined by central pathology. Logistic regression was used to compare prostate inflammation by race, and models were adjusted for demographic and clinical features. Results: Of the 8,046 men, 7,326 were white (91.1%), 184 (2.3%) black, 132 (1.6%) Asian, 323 (4.0%) Hispanic, and 81(1%) unknown. Seventy eight percent of men had chronic and 15% had acute prostate inflammation. Men with chronic inflammation were older (p<0.001), while men with acute inflammation were younger (p<0.001) compared to men with none prostate inflammation. Both acute and chronic inflammation was associated with lower PSA (all p≤0.0001), smaller prostate volume (all p≤0.0001) and geographic region (all p≤0.006). On crude analysis, compared to whites, Asian men were two times more likely to have acute prostate inflammation (OR=1.92, 95%CI: 1.29-2.85, p=0.001), whereas the associations with Hispanic and black race were not significant (all p≥0.39). However, on multivariable analysis, black men were 36% less likely to have acute prostate inflammation (OR=0.64, 95%CI: 0.41-0.99, p=0.04), whereas the likelihood of having acute prostate inflammation remained high in Asians (OR=1.85, 95%CI: 1.25-2.85, p=0.004). No associations by race were found with chronic prostate inflammation. Conclusions: Given that at the population level, black race is a high risk factor for PC and Asian men have lower risk of PC, these data indicate that the presence of acute inflammation in a negative prostate biopsy could be an indication of future PC risk. Further studies to confirm these findings are needed. Clinical trial information: NCT00056407.