Influence of prostate volume in the detection of prostate cancer.

OBJECTIVES: To assess the influence of prostate volume on prostate cancer (CaP) detection in men who underwent repeated sextant transrectal ultrasound biopsy of the prostate. METHODS: Between September 1991 and September 2000, 4376 men underwent sextant transrectal ultrasound-guided biopsy of the prostate. Of the 4376 men, 556 underwent repeat biopsy because of persistent prostate-specific antigen elevation (greater than 4 ng/mL) and/or an abnormal digital rectal examination or suspicious pathologic findings. The percentage of CaP missed on the initial biopsy and detected on the repeat biopsy between arbitrary prostate volumes of less than 50 and 50 cm3 or greater and between less than 37.5 and 37.5 cm3 or greater, the median prostate volumes of men with CaP, were compared. Patient age, prostate-specific antigen level, digital rectal examination findings, and Gleason score in each volumetric cutoff group were also compared. RESULTS: CaP was detected in 22% of men who underwent a repeat biopsy. The percentage of CaP missed on the initial biopsy but subsequently detected on the repeat biopsy consistently increased as the volume increased. A statistically significant difference in the percentage of CaP not detected on the initial biopsy was found between prostate volumes of less than 50 and 50 cm3 or greater and between less than 37.5 and 37.5 cm3 or greater (P <0.05). No statistically significant difference in prostate-specific antigen, age, digital rectal examination, or Gleason score was found between each volumetric cutoff group. CONCLUSIONS: A significant percentage of men are diagnosed with CaP after a repeat biopsy. We have demonstrated that the percentage of CaP missed on the initial biopsy and detected on the repeat biopsy increases as the prostate volume increases. The results of our study suggest that in men with large prostates, traditional sextant biopsies may not be adequate to detect CaP.

The effect of finasteride on the expression of vascular endothelial growth factor and microvessel density: a possible mechanism for decreased prostatic bleeding in treated patients.

PURPOSE: Several studies have confirmed the benefit of finasteride in limiting hematuria from benign prostatic hyperplasia. Vascular endothelial growth factor (VEGF), a potent stimulator of angiogenesis, and microvessel density have been independently evaluated in the mechanism of decreased bleeding observed in patients treated with finasteride. We evaluated the expression of VEGF and suburethral prostatic microvessel density in patients with benign prostatic hyperplasia treated with finasteride. MATERIALS AND METHODS: The study included 24 patients undergoing prostatic surgery for benign disease, of whom 12 were given finasteride for a minimum of 6 weeks before surgery and the remaining 12 served as controls. Sections from the prostatic urothelium and hyperplastic prostate were individually stained for CD34 specific for nascent blood vessels and VEGF. Analysis of each specimen was performed in a blinded fashion. Microvessel density was calculated by counting the number of positively stained blood vessels on 10 consecutive, nonoverlapping, high power fields within the suburethral and hyperplastic prostate compartments. VEGF expression was examined by immunohistochemistry. Statistical analysis of the results was performed using Student's t test. RESULTS: Prostatic suburethral VEGF expression and microvessel density were significantly lower in the finasteride group compared to controls (p <0.05). Differences in VEGF expression and microvessel density at the level of the hyperplastic prostate were not found to be significantly different between the 2 groups. CONCLUSIONS Decreased expression of VEGF by finasteride inhibits angiogenesis and significantly decreases microvessel density in prostatic suburethral tissue. This sequential relationship provides histochemical insight into the mechanism by which finasteride reduces prostatic urethral bleeding.

Decreased suburethral prostatic microvessel density in finasteride treated prostates: a possible mechanism for reduced bleeding in benign prostatic hyperplasia.

PURPOSE: We evaluated the influence of finasteride on prostatic microvessel density to elucidate a mechanism of decreased bleeding in finasteride treated patients with hematuria secondary to benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A total of 22 patients with clinical BPH and gross hematuria who underwent prostate reductive surgery between 1998 and 2000 were prospectively evaluated. The prostate from 10 finasteride treated and 12 untreated patients was immunohistochemically stained for CD-34. Microvessel density analysis was performed by quantifying positive stained blood vessels located within the stroma of hyperplastic nodules as well as in the suburethral portion of the prostate. RESULTS: Mean microvessel density plus or minus standard deviation in finasteride treated patients was significantly lower in the suburethral portion of the prostate versus untreated controls (14.0 +/- 2.8 versus 20.2 +/- 5.3 vessels per high power field, p <0.05). In the nodular hyperplasia there was no statistically significant difference in the treatment and control groups (mean 17.5 +/- 2.8 and 16.7 +/- 4.6 vessels per high power field, respectively). CONCLUSIONS: Finasteride significantly decreases suburethral prostatic microvessel density in patients with BPH, which may explain its efficacy for decreasing BPH associated bleeding.