Prostatic fluid lactic dehydrogenase isoenzyme patterns of prostatic cancer and hyperplasia

LDH isoenzyme patterns were determined in prostatic fluid from 286 patients with a prostate gland judged to be normal, the site of benign hyperplasia on clinical evidence or the site of benign hyperplasia or carcinoma on the basis of histologic evidence. Fluid from 12 of 15 patients (80 per cent) with carcinoma representing all stages and grades of disease showed an LDH-V/I ratio of more than 3. This ratio was exceeded in only 6 of 57 (11.8 per cent) and 14 of 97 (14.4 per cent) patients in whom the diagnosis of benign prostatic hyperplasia without evidence of infection was established histologically or clinically, respectively. An LDH-V/I ratio exceeding 3 was seen commonly in patients with a diagnosis of benign prostatic hyperplasia with a recent history suggesting infection and more than 10 WBCs per high power field on microscopic examination of the prostatic fluid. These observations suggest that an LDH-V/I ratio exceeding 3 in the prostatic fluid in the absence of a history of infection and more than 10 WBCs per high power field on microscopic examination should be regarded as an indication of a high risk of the presence or development of a malignancy of the prostate. The results obtained also support the concept that, in the presence of malignancy, expressed prostatic fluid provides an adequate sample of cells with altered metabolism.