Histopathological effects of finasteride in simple prostatectomy specimens

AIM:The aim of this study is to describe the histopathological effects observed on surgical specimens of patients subjected to finasteride treatment and then operated on simple prostatectomy. METHODS: We have selected 40 patients with symptomatic BPH, eligible to surgery for bladder outlet obstruction. The patients underwent to 6 months treatment (32 cases) or 12 months treatment with finasteride (8 cases). Before and after treatment all the patients underwent to DRE, PSA and free-PSA measurement, TRUS and transrectal biopsy. We have evaluated the histqlogical specimens of BPH after surgery. The control group of untreated BPH patients is represented by 20 pts. RESULTS: When finasteride was given for 6 months, prostatic specimens showed an increase of stroma/epithelium and stroma/lumen ratios, with respect to untreated patients. The size of the ducts and acini was not as uniform as in the other group. In particular, some ducts and acini were still lined by a bistratificd epithelium similar to that of untreated BPH, however, without ondulations of the epithelial border, whereas others were atrophie. Some scattered clusters of small acini with a focally fragmented basal cell layer were observed in 18 out of 32 finasteride-treated cases. In 5 out of 8 simple prostatectomy specimens, from patients treated for one year, extensive lobular atrophy and diffuse squamous and transitional cell metaplasia have been showed. At the periphery of die transition zone, a complex intra-acinar papillary-cribriform proliferation of clear cells without nuclear atypia, similar to clear cell papillary hyperplasia was observed. In the treated patients and untreated BPH, the periurethral region showed stromal nodules. By TRUS, the mean prostatic volume was 74cc before and 63cc after treatment. A reduction higher than 20% has been observed in 6 cases. An alteration of the sonographic pattern has been observed, consisting in a decreased echogenicity and slight parenchyma dishomogenicity specially in transition zone of patients treated for 12 months. A serum PSA reduction was observed, but not a significant decrease of free/total PSA ratio. CONCLUSIONS: Our experience allowed to identify a greater effect of 5α-reductase inhibition on epithelium, which determines an increase of stroma/epithelium and stroma/lumen ratios with lobular atrophy and squamous metaplasia. Such alterations have been observed mainly in the transition zone, but not in the periurethral stroma, with a slight reduction of gland volume.