[Importance of specific prostatic antigen to prostatic volume ratio in the selection of patients for ultrasonography-guided biopsy of the prostate].

US-guided biopsy was performed in 94 patients with suspected lesions at transrectal US. Histology demonstrated carcinoma in 43 cases, benign hyperplasia in 44, and prostatitis in 7. In all cases the prostate specific antigen (PSA) was calculated, by means of US, together with prostatic volume (V). PSA was related to the corresponding gland volume, which resulted in PSA/V index. Subsequently, histology was correlated with both PSA value and PSA/V ratio. Our study showed PSA/V ratio to have higher sensitivity and specificity than absolute PSA value in the diagnosis of prostatic carcinoma. The authors believe prostate US-guided biopsy to be: a) necessary when the suspected area has PSA/V ratio greater than 0.15, and especially when PSA/V greater than 0.30; b) not indicated when echostructural alterations are associated with PSA/V less than 0.15, because they are most frequently due to benign lesions. The combined use of PSA/V ratio and US is therefore suggested to select the patients in whom biopsy is to be performed.