Conjugated Oestrogens (IARC Summary & Evaluation, Volume 21, 1979)
International Agency for Research on Cancer (IARC) - Summaries & Evaluations
CONJUGATED OESTROGENS
VOL.: 21 (1979) (p. 147)
5. Summary of Data Reported and Evaluation
(N.B. - This section should be read in conjunction with the General Remarks on Sex Hormones and with
the General Conclusions on Sex Hormones.)
5.1 Experimental data
Conjugated oestrogens (PremarinR) were tested in only one
experiment in rats by oral administration. The data were insufficient
to evaluate the carcinogenicity of this compound.
5.2 Human data
Case reports and epidemiological studies on steroid hormones used in
oestrogen treatment have been summarized in the section, 'Oestrogens
and Progestins in Relation to Human Cancer'. Because most of
the studies which concerned endometrial carcinoma involved the use of
conjugated oestrogens, the evidence in humans that administration of
these agents is causally related to an increased risk of developing
this cancer is particularly convincing.
5.3 Evaluation
The available experimental data are insufficient to evaluate the
carcinogenicity of conjugated oestrogens in animals. Studies in humans
strongly suggest that the administration specifically of conjugated
oestrogens is causally related to an increased incidence of
endometrial carcinoma.
Subsequent evaluation: Suppl. 7 (1987) (Steroidal oestrogens)
Last updated: 6 April 1998
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Toxicological Abbreviations