[858] Prostate Biopsy Cannot Reliably Identify Patients for Focal Therapy: Correlations of Low-Risk Prostate Cancer on Biopsy with Radical Prostatectomy Findings

P Quann, D Jarrard, W Huang. University of Wisconsin, Madison, WI

Background: Growing evidence of overdetection and overtreatment in many men with low-risk tumors has resulted in the recognition that alternatives to conventional treatment strategies are needed. Organ-sparing focal ablation therapiescryosurgery, high-intensity focused ultrasound (HIFU), photodynamic therapy and radiofrequency therapyhave emerged and are under development. At present, prostate biopsy remains the best means to evaluate patients who might be considered for a focal therapy. Can prostate biopsy reliably do so?
Design: We reviewed matching prostate biopsy and prostatectomy specimens from 142 patients at our institution from 2000 to 2008. The patients selected had low tumor volume (5%), low to intermediate Gleason score (GS6) on biopsy, and underwent subsequent prostatectomy. The pathologic parameters on biopsy (biopsy core number and positive core number) and prostatectomy (GS, tumor volume, laterality, extraprostatic extension, margin positivity and involvement of seminal vesicles and lymph node) were examined.
Results:

Table 1. Low-risk PCa on biopsy (tumor volume 5% and Gleason score 6) with 1 or 2 positive cores and pathologic parameters of matching radical prostatectomy

Bx Core#				Prostatectomy
	GS 7	Vol 10%	Bilateral*	EPE (T3a)	SV+ (T3b)	margin+	LN+
6-12 ( 2+)	42/142 (30%)	64/142 (45%)	82/142 (58%)	9/142 (6%)	2/142 (1%)	29/142 (20%)	0
6-12 (1+)	22/44 (50%)	21/44 (48%)	35/44 (80%)	0	0	8/44 (18%)	0

Bilateral*, unilateral cancer in the biopsy and bilateral in prostatectomy; Vol, tumor volume


Conclusions: The majority of the patients with unilateral cancer on biopsy were found to have bilateral cancer in the prostatectomy specimen regardless of biopsy core numbers. Almost half of the patients had tumor volume 10% of the prostatectomy specimen, and up to 50% of the patients had GS 7. Moreover, a small number of patients with 2 positive cores had cancer extending beyond the prostate. We believe that prostate biopsy has limited value in predicting the pathologic parameters of PCa regardless of how many cores are positive and, therefore, cannot reliably identify patients for a focal therapy.
Category: Genitourinary (including renal tumors)

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 118, Wednesday Morning