[899] Pathologic Predictors of Tertiary Gleason Pattern 5 in Radical Prostatectomies Provide a Rationale for Total Embedding of Selected Prostates with Gleason Score 7 Cancer

LD True, HG Sim, PH Lange, WJ Ellis, DW Lin, JL Wright. University of Washington, Seattle

Background: Prostate cancer patients with Gleason score 7 cancer and a tertiary Gleason pattern 5 component (TP5) have biochemical recurrence rates similar to those of patients with Gleason score 8 to10 cancer (Pan, '00). Given concerns about unnecessary cost and time, strategies have been developed to sample only sufficient tissue from radical prostatectomies (RP) as to not miss margin positivity, extra-prostatic extension and to obtain an accurate Gleason score (Sehdev, '01; Cohen, '94). We questioned whether we could identify pathologic parameters of Gleason score 7 cancers that would identify those cancers that had a tertiary pattern 5 component and that would thus warrant total embedding of the prostate to find that component.
Design: 723 men who underwent RP with Gleason score 7 cancer and no neoadjuvant therapy were identified. Pathologic correlates of TP5 were determined using multivariate logistic regression analysis adjusting for pathologic stage, surgical margin status, preoperative serum PSA, tumor volume, and prostate gland volume.
Results: Of 723 men who underwent RP with Gleason score 7 cancer, 92 (13%) had a tertiary pattern 5 component (TP5). Compared with patients without TP5, patients with TP5 had higher tumor volume (median 4.0 cc vs 2.3 cc, p < 0.0001), more commonly had primary Gleason pattern 4 (61% vs. 20%, p < 0.001) and exhibited extracapsular extension (52% vs. 25%, p < 0.001). In multivariate analysis, patients with primary Gleason pattern 4 (OR 6.16, 95% CI 3.68-10.3) and extracapsular extension (OR 2.63, 95% CI 1.52-4.53) were more likely to have TP5. Additionally, increased tumor volume was associated with an increased probability of having TP5 (p < 0.001).
Conclusions: A tertiary Gleason pattern 5 component in a Gleason score 7 cancer is more frequent in patients with more voluminous, higher stage tumors in which the primary Gleason pattern is pattern 4. Since the pattern 5 component represented < 10% of each tumor and could only be found by total embedding of each prostatectomy specimen (being present in only one block in > 90% of our cases), we propose that RP specimens from patients whose prostate carcinoma is Gleason score 7 with a primary pattern that is 4, a tumor volume > 4 cc, and extracapsular extension be totally embedded to identify this subgroup of high risk patients for possible adjuvant therapy.
Category: Genitourinary (including renal tumors)

Monday, March 9, 2009 1:30 PM

Platform Session: Section A, Monday Afternoon