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


VOL.: 6 (1974) (p. 135)

5. Summary of Data Reported and Evaluation

(N.B.: This section should be read in conjunction with the section 'General Conclusions on Hormones'.)

5.1 Animal carcinogenicity data

Progesterone was tested by subcutaneous or intramuscular injection in mice, rats, rabbits and dogs and by subcutaneous implantation in mice and rats. It was tested alone only in mice and dogs; in rats and rabbits it was always given in combination with other chemicals; in mice it was also tested in combination with other carcinogens.

When given alone, it increased the incidence of ovarian, uterine or mammary tumours in mice, while the experiment in dogs was of insufficient duration to allow an assessment to be made.

The administration of progesterone to intact or castrated mice and rats and to rabbits in combination with polycyclic aromatic hydrocarbons or with 2-acetylaminofluorene and/or oestrogen variously affected the incidence and the histological type of the tumours produced by these known carcinogens (mainly mammary, uterine and vaginal tumours). In particular, progesterone enhanced the incidence of tumours produced by these known carcinogens, but only when given after and not before their administration.

5.2 Human carcinogenicity data

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

Subsequent evaluations: Vol. 21 (1979); Suppl. 7 (1987) (Progestins; Combined oral contraceptives)

Last updated: 20 March 1998

    See Also:
       Toxicological Abbreviations
       PROGESTERONE (JECFA Evaluation)
       Progesterone (IARC Summary & Evaluation, Volume 21, 1979)