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


VOL.: 21 (1979) (p. 365)

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

Chlormadinone acetate was tested in mice, rats and dogs by oral administration. When given alone to dogs, chlormadinone acetate produced mammary tumours. When given to mice in combination with mestranol, it increased the incidence of pituitary tumours in animals of both sexes; in combination with ethinyloestradiol, it increased the incidence of mammary tumours in intact and castrated male mice of one hybrid strain.

Chlormadinone acetate has been reported to be embryolethal and teratogenic when given during the organogenesis stage in some species.

5.2 Human data

No case reports or epidemiological studies on chlormadinone acetate alone were available to the Working Group. Epidemiological studies on steroid hormones used in oestrogen-progestin contraceptive preparations have been summarized in the section, 'Oestrogens and Progestins in Relation to Human Cancer'.

5.3 Evaluation

There is limited evidence for the carcinogenicity of chlormadinone acetate in dogs. In humans, oral contraceptives containing oestrogens in combination with progestins have been related causally to an increased incidence of benign liver adenomas and a decreased incidence of benign breast disease.

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluation: Vol. 6 (1974)

Subsequent evaluation: Suppl. 7 (Progestins; Combined oral contraceptives)

Last updated: 6 April 1998

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       Toxicological Abbreviations