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'.
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