We applied both hormonal and antiestrogen treatment in female Wistar rats t
o analyze the estrogen dependence of the growth of sarcomas induced with 9,
10-dimethyl-1,2-benzanthracene. Animals bearing tumors of 10 mm in diameter
were divided at random into five groups and submitted to different treatme
nts during 24 weeks. The treatment with ovariectomy and tamoxifen in tumor-
bearing animals resulted in tumor growth suppression and prolonged survival
by a protection against the lethal tumor. On the other hand, the estrogen
treatment exerted an adverse effect showing a faster growth of the tumors a
nd a great decrease in survival. In summary, the antiestrogen treatment can
have an antitumor effect in mesenchymal tumors, possibly by modifying the
immunological status of the host.