Objective: Depletion of serum LH by LHRH agonists is used as a therapeutic treatment in hormone-sensitive prostate cancer (PCa). However, little information on serum LH in different patient groups is available.
Methods: Patients with biopsy-proven PCa, men with BPH (biopsy-proven absence of PCa), two subgroups (serum PSA <4 ng/ml; PCa and BPH), and a PCa cohort before and after radical prostatectomy were analyzed for serum LH, testosterone (T), dihydrotestosterone (DHT), total and free PSA by immunological procedures.
Results: PCa patients with cancer volumes >10 cm(3), or with advanced Gleason scores, had significantly lower LH values than men in a cancer-free control group (PSA <4 ng/ml). Eight weeks after radical prostatectomy, LH levels had returned to the level of the control group (p<0.0001). These alterations were not accompanied by corresponding changes of serum androgens. Introduction of a PSA/LH ratio appeared to increase the differences between BPH and PCA groups ranked according to Gleason scores, versus PSA or LH alone. However, the calculation of ROC curves indicated that PSA/LH ratios may not improve the discrimination of malignant and benign forms of the disease, compared to presently used parameters.
Conclusions: A significant reduction of circulating LH is observed in the most advanced forms of PCa. The effect does not come about by T- or DHT-mediated feedback inhibition. Since LH values after prostatectomy returned to practically the same levels as seen in the control group (BPH with <4 ng/ml PSA), it appears that the healthy prostate has no marked influence on serum LH while advanced PCa induces a decrease in serum LH.