Importance of prostate volume for detection of prostate cancer by first sextant biopsy in high-risk patients

The aim of this study was to evaluate the relevance of prostate gland volume, transitional zone volume, and transitional zone index for the detection of prostate cancer by the first sextant biopsy.
Material and methods. A total of 121 men with high risk of prostate cancer were included in our study (prostate-specific antigen level higher than 4 ng/mL and/or pathological digital rectal examination). We consulted the patients in Outpatient Department of Kaunas University of Medicine Hospital during 2003–2006. Total prostate volume and transition zone volume were measured, and all patients underwent transrectal ultrasoundguided sextant biopsy of the prostate. According to histological results of prostate biopsy, patients were divided into two groups: benign group (benign prostate hyperplasia and high-grade intraepithelial neoplasia) and prostate cancer group. Statistical analysis was made by SPSS (Statistical Package for Social Sciences) 12.0.1 for Windows.
Results. After histological examination, prostate cancer was detected in 20.7% of patients (n=25). Prostate cancer was found in 24.6% of patients with a total prostate volume of less than 60 cm3 and only in 8.2% of patients with a total prostate volume greater than 60 cm3 (P=0.026). Prostate cancer was found in 27.1% of patients with transition zone volume smaller than 30 cm3 and only in 7.5% of patients with transition zone volume greater than 30 cm3 (P=0.007). A statistically significant difference was found when patients were divided into the groups according to transition zone index: when transition zone index was lower than 0.45, prostate cancer was detected in 37.1% of patients, and when transition zone index was higher than 0.45, prostate cancer was observed in 9.1% of patients (P=0.001). The possibility to detect prostate cancer was 5.9 times higher in patients with transition zone index lower than 0.45.
Conclusions. Prostate cancer detection rate by first sextant prostate biopsy in patients with elevated prostate-specific antigen level and/or pathological digital rectal examination was higher when total prostate volume was less than 60 cm3, transition zone was less than 30 cm³, and transition zone index was less than 0.45.