Prognostic usefulness of serum lactic dehydrogenase and its fifth isoenzyme levels in carcinoma of the prostate.

Antiandrogenic treatment with castration, intravenous diethylstibestrol diphosphate and oral estradiol benzoate was given to 51 patients with prostatic carcinoma. The interrelationship between the clinical response to this treatment and the changes of serum lactic dehydrogenase (SLDH) and SLDH isoenzyme V fraction (SLDH-V) level was studied. Pretreatment SLDH level is significant in regard to the 5-year survival rate. Response of SLDH and SLDH-V levels to antiandrogenic treatment has no significant influence on the 5-year survival rates. As regard the index of the 5-year survival rate in patients with prostatic carcinoma, SLDH-V was almost as specific as SLDH.