Long-term effects of finasteride on prostate tissue composition

Abstract

Objectives. To determine the long-term effects of finasteride treatment on prostate tissue composition; to relate these effects to clinical outcomes; and to test the hypothesis that finasteride exerts a selective or preferential action on the transition zone. Methods. Nineteen men with symptomatic benign prostatic hyperplasia (BPH) who completed a 6-month double-blind trial of finasteride were enrolled in a 24-month open-label extension study of drug responders. Magnetic resonance imaging and prostate biopsy for morphometric analysis were performed together 70 times: at baseline (n ϭ 19), after treatment periods of intermediate duration (6 to 18 months, n ϭ 32), and after long-term drug treatment (24 to 30 months, n ϭ 19). At baseline, prostate volume averaged 51 cc, of which 57% was transition zone. Results. Decreases in symptom score, dihydrotestosterone and prostate-specific antigen levels, and prostate volume occurred at 6 months (P Ͻ0.01), stabilized, and were maintained without further long-term decreases. Prostate epithelium contracted progressively from baseline (19.2% tissue composition; 6.0-cc volume; 3.2 stroma/epithelial ratio) to intermediate (12.5%, 3.3 cc, and 5.6, respectively) to long-term treatment (6.4%, 2.0 cc, and 17.4, respectively, P Ͻ0.01 for all). Percent epithelial contraction was similar in the peripheral and transition zones (P ϭ NS). The transition zone remained a relatively constant proportion (53% to 58%) of whole-prostate volume from baseline to long-term observation. Conclusions. Long-term finasteride treatment (24 to 30 months) results in a marked involution of the prostate epithelium, which continues to progress for many months after clinical effects stabilize. The effect on the epithelium is similar in the peripheral and transition zones for both morphometric and volumetric changes. Progressive contraction of the prostate epithelium appears to constitute the underlying mechanism for sustained action of finasteride. UROLOGY 53: 574-580, 1999.

Prostate magnetic resonance imaging: Multiexponential T2 decay in prostate tissue

“…The volume fraction occupied by glandular lumen in prostate tissue varies between the anatomic zones and between patients. Studies incorporating quantitative morphology have reported values between 20% and 40% in normal glandular prostate tissue (17,18). These numbers are similar to the signal fractions found in our study, supporting the notion of prostate fluid being the source of the long T2 component.…”

Clinical value of prostate segmentation and volume determination on MRI in benign prostatic hyperplasia

“…Tempany et al (14) used 1.5 Tesla (T) MRI and found a larger reduction in the peripheral zone, although it was not statistically significant. Other longitudinal, double-blinded studies using volumetric assessment with TRUS found decreases in both peripheral zone volume and transition zone volume (10,15,16). Furthermore, one of these studies detected a significant positive correlation between transition zone index (i.e., the transition zone volume as a percentage of the whole prostate gland) and the change in prostate volume for patients on dutasteride (10).…”

Predictors of Enucleation and Morcellation Time During Holmium Laser Enucleation of the Prostate

“…The impact of 5ARIs on prostatic tissue quality is not well understood but 5ARIs are known to affect the glandular to stromal ratio with an overall reduction in glandular tissue [27][28] .…”

“…Dual irrigation is used to keep the bladder full and to improve visualization. Irrigation was placed approximately [24][25][26][27][28][29][30] inches above the level of the bladder. Unusually tough prostatic tissue (termed "beach balls") may occasionally be encountered during enucleation which can prolong morcellation time.…”