Three-Dimensional Conformal Radiation Therapy of Spontaneous Benign Prostatic Hyperplasia in Canines

The purpose of this study was to determine the effect and possible mechanism of three-dimensional conformal stereotactic radiation therapy (3D-CRT) for the treatment of spontaneous benign prostatic hyperplasia (BPH) in a canine model. Eight canines (7-15 years old) with spontaneous benign prostatic hyperplasia (prostate volume >18 cm3) were used as experimental models. The prostates were directly exposed to 3D-CRT at a total dose of 14 Gy. Serum prostate-specific antigen (PSA) and prostate acid phosphatase (PAP), prostate volume (measured by transrectal ultrasound), apoptosis index [AI, measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)], proliferation index [PI, measured by proliferating cell nuclear antigen (PCNA) expression], alpha-SMA, Bax, and bFGF were measured before and after radiation therapy. Histopathology of the prostate, rectum, and bladder tissue was also examined before and after irradiation. 3D-CRT treatment significantly decreased prostate volume, and the PI, PSA, and alpha-SMA, but significantly increased the AI, and had no effect on PAP. There was no evidence of Bax expression before or after irradiation. Irradiation led to no detectable symptoms of diarrhea or changes in stool, but did lead to minor bladder injury, based on light microscopy, scanning electron microscopy, and transmission electron microscopy. In our canine model, 3D-CRT is an effective, noninvasive treatment of BPH that is associated with minimal side effects. Our treatment appeared to reduce prostate size by treatment of the underlying pathological processes.