[929] Histologic Variables and Patient Outcome in Prostate Biopsies with Atypical Small Acinar Proliferation Reclassified as Benign, ASAP or Cancer by Re-Review

Michael G Keeney, John K Schoolmeester, Ryan E Swapp, Christine M Lohse, Brant A Inman, Thomas J Sebo. Mayo Clinic, Rochester, MN

Background: ASAP in prostate biopsy (bx) is a descriptive term reflecting glands that quantitatively and/or qualitatively lack sufficient features for carcinoma (Ca) diagnosis (dx). ASAP dx will impact the clinical management of re-bx. Studies show the prevalence of ASAP bx dx ranges from 0.7 to 9% and patients with ASAP dx have 40%-50% Ca detection risk at re-bx.
Design: 96 patients were identified with a bx classified as ASAP (1994–2005). All H&E and immunostained slides were blindly re-reviewed by an experienced urologic pathologist (UP), and re-classified as benign, ASAP or Ca. Features assessed were age, digital rectal exam, total bx cores, number (#) ASAP foci, # cores positive (+) for ASAP, # ASAP glands, ASAP linear extent (mm), percent (%) ASAP nuclei with nucleoli, prior bx, # prior bxs, prior bx dxs, bx seen with non-study UP, laterality of ASAP, infiltrative growth of ASAP, % ASAP nuclei with nucleoli, ASAP nucleolar size, irregularity and hyperchromasia of ASAP nuclei, intraluminal mucin/crystalloid, cytoplasmic amphophilia, background atrophy, inflammation, and high-grade (HG) PIN, and immunostain (CK903 and p504S) results. Clinical follow-up was obtained.
Results: ASAP was classified as ASAP in 55 (57%), benign in 30 (31%) and Ca in 11 (11%) cases. Factors linked (p<0.05) to reclassification(first % more aligned with Ca re-classification; second % more aligned with benign) were: laterality of ASAP (unilateral 89%, bilateral 11%), # of ASAP foci (1, 21%; >1, 89%), cores with ASAP (1, 20%; >1, 80%), infiltrative growth (present 52%, absent 48%), atrophic background (absent 55%, present 45%), HGPIN (present 56%, absent 44%), nucleoli size (large 31%, medium 27%, small 19%, none 23%), intraluminal mucin (present 10%, absent 90%), cytoplasmic amphophilia (present 49%, absent 51%), and inflammation associated with ASAP (present 7%, absent 93%). 84 patients had clinical information following ASAP bx and 33 (39%) developed Ca. 24, 49, and 11 had re-review dx of benign, ASAP, and Ca of whom 4 (17%), 21 (43%), and 8 (75%) developed Ca (p=0.005). 17 of patients with Ca were treated with radical prostatectomy (RP). RP Ca Gleason score was <7 (65%), =7 (30%), and >7 (12%). 14 Ca (82%) confined to prostate at RP.
Conclusions: Retrospective re-review by UP of prostate bxs initially diagnosed as ASAP identified 10 parameters linked to reclassifying ASAP as benign or Ca. Reclassification was linked to lower (benign–25%) or higher (Ca–75%) risk of Ca detection on repeat bx. Only half of patients treated with RP and 82% had confined disease.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 117, Wednesday Morning

 

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