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


VOL.: 21 (1979) (p. 491)

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

Progesterone was tested by subcutaneous and intramuscular injection in mice, rats, rabbits and dogs and by subcutaneous implantation in mice and rats. It was tested alone in mice and dogs; in rats and rabbits it was always given in combination with other sex hormones.

When given alone, progesterone increased the incidence of ovarian, uterine and mammary tumours in mice; the data from dogs were insufficient to evaluate carcinogenicity.

Neonatal treatment with progesterone enhanced the occurrence of precancerous and cancerous lesions of the genital tract and resulted in increased mammary tumorigenesis in female mice.

5.2 Human data

No case reports or epidemiological studies on exogenous progesterone were available to the Working Group.

5.3 Evaluation

There is limited evidence for the carcinogenicity of progesterone in experimental animals. In the absence of epidemiological data, no evaluation of the carcinogenicity of progesterone to humans can be made.

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluation: Vol. 6 (1974)

Subsequent evaluation: Suppl. 7 (Progestins)

Last updated: 7 April 1998

    See Also:
       Toxicological Abbreviations
       PROGESTERONE (JECFA Evaluation)
       Progesterone (IARC Summary & Evaluation, Volume 6, 1974)