EXPERIENCE WITH LOW-DOSE ESTROGEN IN THE TREATMENT OF ADVANCED PROSTATE-CANCER - A PERSONAL VIEW

Objective To re-evaluate the treatment of advanced prostatic carcinoma with diethylstilboestrol (DES) in low dosage in relation to the degre e of suppression of plasma testosterone. Patients and methods The stud y comprised 106 patients with advanced carcinoma of the prostate (89 w ith T3/4 M1 and 17 with T3/4 N0/1 M0) who were treated with 1 mg/day o f DES. The response was assessed clinically and by the change in plasm a prostate specific antigen, prostatic acid phosphatase and alkaline p hosphatase, and plasma testosterone was monitored regularly. In a few patients it was possible to reduce the dose to 0.5 mg/day DES; in othe rs, the initial response was not sustained and they were treated with an increased dose of DES or bilateral orchidectomy. Results Seventy pa tients (Group 1) showed a sustained response to 1 mg/day of DES (0.5 m g/day in three) and 50 remained in remission at a mean of 21 months of treatment. Of the 36 patients offered secondary treatment, 12 (Group 2) responded with a second remission, Only 27% of patients had mean te stosterone levels in the castrate range (0-2 nmol/L) but most in Group 1 had mean levels of <10 nmol/L, whilst in 10 of the 12 patients in G roup 2, the level was >10 nmol/L. Overall times to progression and dea th were comparable with the results of conventional monotherapy or com bination treatment and complication rates were acceptable. Conclusion Low-dose oestrogen therapy (1 mg/day of DES) is cheap, effective and c aused few side-effects, none of which was life-threatening. In many pa tients, only minimal suppression of the plasma testosterone was requir ed and the response appeared to be qualitative, although there was con siderable variation in the threshold of response. A randomized trial o f oestrogen, in a minimal dose adjusted to the requirements of the ind ividual patient, against conventional hormone treatment now seems just ified.