Prostate‐specific antigen and prostate gland volume: Correlation and clinical application

We studied 103 patients seen in our Prostate Cancer Detection Clinic to determine whether a correlation exists between serum prostate‐specific antigen (PSA) values and ultrasound‐calculated prostate gland volume. Seventy men (68%) had a PSA value ≤ ng/ml (our upper limit of normal). The men were subclassified by prostate gland volume at arbitrary break points. Twenty‐five men (24%) had a prostate gland volume ≤ 25 cm³; in 96%, the PSA value was ≤ 4 mg/ml. Further analysis revealed that the percentage of men with a normal serum PSA value decreased as the prostate gland volume increased; 65.6% of the group with a gland volume between 25 and 50 cm³ (40 of 61) and 35.5% of the group whose prostate volume exceeded 50 cm³ (6 of 17) had PSA values ≤4 ng/ml. Four men had PSA values ≥20 ng/ml; all had prostate cancer. Cancer was diagnosed in four additional patients, three with PSA values between 5 and 10 ng/ml and one with a PSA value <4 ng/ml. There appears to be a direct relationship between prostate gland volume and PSA value, as well as a cancer value threshold. The clinical implications of these findings are discussed.