[874] The Cribriform Pattern in Prostate Cancer Predicts PSA Failure

KA Iczkowski, KC Torkko, W Huang, FG LaRosa, S Cook. Univ. Colorado, Aurora, CO; Univ. Wisconsin, Madison, WI

Background: Gleason grading and clinical significance of cribriform structures (CS) in prostate cancer are controversial. The International Society of Urologic Pathologists in 2005 advocated that most CS be graded as Gleason 4. Although several surveys and consensus studies have been published, outcome-based data on CS are lacking.
Design: Of 619 men from 2 institutions with prostatectomy slides and follow-up available, 46 men had documented PSA failure and available slides. The failures were matched with 63 non-failure controls according to follow-up duration, grade, stage, and age. Presence and extent of CS in each case were evaluated by two urologic pathologists, working independently, blinded to outcome. Structures with slit-like spaces, stromal cores, mucin, or intervening stroma were not counted as CS. Group differences in age were assessed by t-test, in presence of CS by chi-square test, and in other variables by Wilcoxon rank sum test. Pathologist agreement on presence of CS was assessed by McNemar test, and on other variables, by Spearman correlation.
Results: Data concordance between pathologists was generally strong. The PSA failures had median 5.1 years follow-up, versus 5.9 for controls. Failures' mean age at surgery was 57.8 years, preoperative median PSA was 5.97 ng/mL, and mean Gleason score was 6.9; corresponding values for control non-failures were 58.4; PSA 6.10; and 6.8 (all p=NS). Presence of any CS in the PSA failure group and non-failures, respectively, was 32/46 cases (70%) versus 16/63 (25%) (p<0.0001). Among cases with CS, the CS constituted 22% of tumor volume in failures versus 3% in non-failures, or, averaged over all cases with or without CS, 8.0% vs. 1.8% (p<0.0001). Mean number of CS in the totally submitted prostate was 20.0 in failures versus 9.9 in non-failures (p<0.0001). Mean diameter of CS was 4.04 mm in failures versus 2.51 mm, significant for the Colorado group (p=0.008) but not the Wisconsin group (p=0.28) or overall.
Conclusions: Men with PSA failure are more likely to have tumor containing CS than matched non-failure patients with identical Gleason score. Among cases with CS, the CS tend to be more numerous and occupy a greater percent of tumor in men that suffer PSA failure than in matched non-failures. Despite CS having a pushing border, unlike the infiltrative pattern characteristic of Gleason grade 3 or 4 cancer not otherwise specified, it can be speculated that extensive CS's may allow the tumor to gain vascular access or escape immune surveillance.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 2:00 PM

Platform Session: Section A, Monday Afternoon


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