Rapid post-castration decline in serum canine prostatic specific esterase (CPSE) and prostatic volume in dogs with benign prostatic hyperplasia

The objectives of this study were to quantify temporal changes in prostatic volume and serum CPSE concentrations in dogs with benign prostatic hyperplasia (BPH) (n = 6) following surgical castration, and to evaluate the potential of CPSE as a biomarker for monitoring prostatic regression. Prostatic volume was determined by transabdominal ultrasonography, and serum CPSE concentrations were measured at baseline (Week 0) and at Weeks 1, 2, and 4 postcastration. The mean (±SE) prostatic volume before castration was 11.4 ± 1.9 cm3 and decreased significantly to 6.3±1.1 cm3 by Week 1 (P < 0.001), representing a reduction to approximately 56% of the baseline value. Smaller progressive declines were observed at subsequent time points up to Week 4 (P > 0.05). In parallel, serum CPSE concentrations dropped sharply from 133.8 ± 19.8 ng/mL at baseline to 16.2 ± 7.6 ng/mL by Week 1 (approximately 10% of the initial value, P < 0.05), with minimal additional change thereafter (P > 0.05). A strong positive correlation (ρ = 0.720, P < 0.001) was observed between prostatic volume and serum CPSE levels. These findings indicate that both prostatic volume and serum CPSE concentrations decrease markedly within the first week after castration, highlighting CPSE as a minimally invasive biomarker for monitoring prostatic involution and postoperative recovery in dogs. Persistent elevation of CPSE levels or failure to reduce prostatic volume beyond one week after castration may warrant further evaluation for underlying conditions, such as chronic prostatitis or prostatic neoplasia.