Can combined DES and LHRH depot therapy (ICI 118630) prevent endocrinologic and clinical flare-up in metastatic prostate cancer?

Medical castration obtained with luteinizing hormone releasing hormone (LHRH) analogues in patients with prostate cancer is now well established. To block the initial stimulation of testosterone production and prevent the risk of the so-called flare-up with this medication, we investigated short-term combination therapy with 1 mg of diethylstilbestrol (DES). Fourteen previously untreated patients with histologically proved metastatic prostatic carcinoma were treated with 1 mg DES po daily one week prior to the initiation of therapy with LHRH analogues depot injection of Zoladex (ICI 116630) and continued during four weeks after the first depot injection. LHRH depot form was maintained as long as patients experienced clinical benefit. Endocrinologic results show that in spite of 1 mg of DES a significant increase of testosterone is still observed in the first week after injection of the LHRH depot form. Hence, this combination is not useful to prevent endocrinologic and clinical flare-up in patients with prostate cancer treated with LHRH analogues.