[934] Inflammation Confined to the Stromal Compartment in Benign Prostate Biopsy May Be Associated with Decreased Risk of Subsequent Prostate Cancer (PCa).

Benjamin A Rybicki, Andrew Rundle, Deliang Tang, Nilesh S Gupta, Dhananjay A Chitale, Oleksandr N Kryvenko. Henry Ford Hospital, Detroit, MI

Background: Benign changes ranging from atrophy and inflammation to prostatic intraepithelial neoplasia (PIN) are common findings on prostate core needle biopsies. Only high grade PIN is recommended to be included in surgical report although atrophy and inflammation may be precursors of PCa. The disease risk associated with these potential disease risk factors has not been assessed in a controlled study.
Design: A matched case-control study of 316 PCa-control pairs nested within a historical cohort of healthy men with a benign prostate specimen from 1991-2002. Eligible cases were diagnosed with PCa at least one year after cohort entry. Controls were selected through incidence density sampling and matched to cases on date and age at cohort entry, race, and type of specimen. The initial benign specimens and controls were reviewed by one pathologist for presence of PIN, atrophy (simple, lobular, and partial) and inflammation (glandular and/or stromal). Conditional logistic regression was used to model the independent risk of each of these conditions.
Results: After adjusting for the effect of the other factors, only PIN was found to significantly increase the risk for PCa (Odds Ratio (OR) = 1.92). Presence of inflammation was associated with decreased risk for PCa (OR = 0.69), but this decreased risk was primarily for inflammation within the stromal compartment (OR = 0.63). Inflammation in the glandular or periglandular regions was not associated with increased risk. Irrespective of whether inflammation was present or absent, presence of atrophy failed to show an increased PCa risk. When stratified by PSA level (<4 or >4 ng/ml) at time of initial assessment, the strongest association of PIN (OR= 2.35) and stromal inflammation (OR = 0.51) with PCa was in cases with PSA >4 ng/ml. PIN primarily increased the risk for PCa diagnosed within three years of initial assessment (OR=3.77), whereas the negative association between stromal inflammation and PCa was stronger three years or more after initial assessment (OR=0.57).
Conclusions: We find that the association of PIN with increased risk for subsequent PCa is seen mainly in patients with PSA >4 ng/ml and within three years of initial assessment. There is no increased risk for PCa associated with atrophy and/or glandular inflammation. Patients with stromal inflammation who fail to develop PCa within three years after initial assessment are up to half as likely to develop PCa upon further follow-up. These previously unreported findings may be used by clinicians in managing patients with high PSA but a negative biopsy.
Category: Genitourinary (including renal tumors)

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 76, Wednesday Morning


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