[1002] Low-Risk Prostate Cancer Patients on Active Surveillance: Utility of Immunohistochemistry

Julio Poveda, Ahmed Eldefrawy, Saleem Umar, Mark Soloway, Merce Jorda. University of Miami, Miami, FL; Jackson Memorial Hospital, Miami, FL

Background: Men with low-risk prostate cancer (LRPCa) are placed on an active surveillance (AS) protocol at the University of Miami Health System, which includes periodic prostate core needle biopsy sampling. Our aim is to determine whether the decision to maintain patients on AS is affected by immunohistochemical (IHC) staining on surveillance biopsies.
Design: We retrospectively reviewed surveillance prostate core needle biopsy specimens of 236 men on AS for LRPCa. Data accumulated included number of positive cores, Gleason sum and percentage of tumor involvement in each core, and if IHC was used. Data from initial diagnostic biopsies was not included in this study. As per our AS protocol, triggers for the discontinuance of surveillance and initiation of active treatment include Gleason grade ≥4, >2 cores being involved by tumor, or tumor volume of >20% in any core. We determined whether IHC triggered treatment by upgrading Gleason grade or detecting a higher tumor volume compared to H&E staining.
Results: 499 prostate biopsies performed in 236 men on AS were reviewed. Biopsies were performed between June 2002 and Aug 2012. Of 152 (64.5%) of patients on AS, IHC was used in 248 (49.5%) biopsies. The median number of cores evaluated by IHC in each biopsy session was 2.0 (range 1.0-12.0). The results from IHC changed the management in 10 out of 236 patients on AS. Eight patients were found to have >2 positive cores and 2 patients had >20% of cancer in a single core. No patient was determined to have Gleason grade ≥4 by IHC.
Conclusions: Although IHC was used in 64.5% of men on AS and in nearly half of the total biopsies performed, it changed the management in only 4.2% of men on AS. Therefore, IHC should be considered if positivity could potentially lead to initiation of active treatment.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 140, Wednesday Afternoon

 

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