Cisobitan in treatment of prostatic cancer. A prospective controlled multicentre study.

Cisobitan, an organosilicon compound with estrogenic and antigonadotropic properties has been evaluated clinically in comparison with an estrogen preparation. In a multicenter study a total of 140 patients with well and moderately well differentiated prostatic cancer were randomly allocated to treatment with Cisobitan or Estradurin/Etivex, 70 to each group. Of 34 patients with poorly differentiated prostatic cancer 18 were given Cisobitan--and 16 were given Estracyt-treatment. Among the patients with well and moderately well differentiated prostatic cancer there were, disregarding mortality, no major differences in subjective, objective or laboratory response to the two kinds of treatment. The pattern of side effects was similar, but oedema requiring diuretics occurred more often in the estrogen treated group. There was a significant difference in mortality at 12 months between the groups, two in the Cisobitan group and ten in the estrogen treated group. Cancer was the cause of death in two patients in the estrogen treated group. All other patients succumbed in cardiovascular diseases. At 24 months the difference in mortality rate was less pronounced: Another ten patients had died in the Cisobitan treated group and seven among the estrogen treated patients. Cancer was responsible for the deaths in seven of the Cisobitan patients compared to four of the estrogen treated patients. Within three years one more patient in both groups had died. Of the 34 patients with poorly differentiated cancer, twelve were alive at the 24 months' follow up, six in the Cisobitan group and six in the Estracyt group.