[1038] Comparison of Partial Sampling Methods in Radical Prostatectomy Specimens

Saleem A Umar, Viacheslav Iremashvili, Liset Pelaez, Saba Yasir, Swetha Paluru, Soum Lokeshwar, Murugesan Manoharan, Mark Soloway, Merce Jorda. The University of Miami, Jackson Health System, Sylvester Comprehensive Cancer Center, Miami, FL

Background: Extraprostatic extension (EPE) and surgical resection margin (SRM) status of a radical prostatectomy (RP) specimen directly impacts subsequent post-surgical patient management. There is no consensus as to whether partial sampling can provide sufficient information about these two parameters. Furthermore, no agreement has been reached in regards to which partial sampling method is most informative. The aim of our study was to evaluate different methods of partial sampling described in the literature and their association with rates of missed positive SRMs and/or EPE.
Design: We reviewed 697 entirely sampled RP specimens with positive SRM and /or EPE. Using schematic templates accompanying each case, we were able to analyze four previously described partial sampling methods: A) three representative sections of the gland B) alternate “slices” C) alternate “slices” representing the posterior aspect of the gland in addition to one of the mid-anterior D) every “slice” representing the posterior aspect of the gland in addition to one of the mid-anterior, supplemented by additional sections based on tumor size. The rates of positive SRM and EPE that could be identified using each of these techniques were compared to the actual rates obtained by entire sampling using the McNemar test.
Results: Of 697 completely sampled RP specimens (mean number of slides examined = 31), solely positive SRMs were identified in 387 (55.5%) cases, solely EPE in 136 (19.5%) cases, and both were identified in 174 (25%) cases. The partial sampling methods would have required examination of an average of 16 (A), 18 (B), 13 (C) and 20 (D) slides. All alternative sampling methods were associated with missing a significant number of the analyzed aggressive pathological features (p<0.001 for all pairs of comparison), however the numbers of missed cases varied considerably. Positive SRMs (561 patients) and EPE (310 patients) would have been missed in 98 (18%) and 142 (46%) patients using method A, 78 (14%) and 94 (30%) using method B, 125 (22%) and 146 (47%) using method C, and 36 (6%) and 22 (7%) using method D.
Conclusions: Partial sampling method D consisting of every “slice” representing the posterior aspect of the gland in addition to one of the mid-anterior, supplemented by additional sections based on tumor size, appears to be superior to the other evaluated methods, missing 7% or less of cases with positive SRMs and/or EPEs.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 1:00 PM

Poster Session II # 181, Monday Afternoon

 

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