[The correlation between the level of prostate-specific antigen and prostate gland volume in the early diagnosis of prostatic cancer].

One hundred and eighty six patients (Pts) presenting with either an abnormal per rectum examination (P.R. suggestive of prostatic cancer (P.Ca) (excluding stage T3) or a prostatic specific antigen (P.S.A.) level greater than or equal to 2.5 ng/ml (radioimmunoassay) were submitted to transrectal ultrasonography (T.R.U.) using a 7 MHz transducer. The prostatic volume (Vol.P) was systematically calculated during T.R.U. and correlated with the P.S.A. level. Six systematic multiple ultrasound-guided biopsies (S.M.U.B.) were performed in the 2 prostatic lobes (3 per lobe) regardless of the result of T.R.U. In the 111 patients in whom the S.M.U.B. were negative, a highly significant correlation (p < 0.001) was observed between the serum P.S.A. level (y) and the prostatic volume (Vol.P): y = (4.13 +/- 0.15 Vol.P) +/- 8.43. In the 75 Pts with P.Ca, the P.S.A./Vol.P correlation was significantly different (p < 0.05) from the straight line of regression with the previous standard deviation. A similar difference in correlation (p < 0.05) was observed in the sub-group of 14 Pts with P.Ca despite normal P.R. and T.R.U. These results suggest: 1) that there is a correlation between the Vol.P measured by T.R.U. and the P.S.A. level in patients with negative S.M.U.B. 2) that the absence of correlation is highly suspicious of P.Ca and requires S.M.U.B. 3) that there is a 15% incidence of P.Ca in the sub-group of Pts with normal P.R. and T.R.U. which are only detected by the raised P.S.A. not correlated with the volume of the prostate.