International Agency for Research on Cancer (IARC) - Summaries & Evaluations


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

    See Also:
       Toxicological Abbreviations