International Agency for Research on Cancer (IARC) - Summaries & Evaluations
VOL.: 21 (1979) (p. 327)
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
Oestriol was tested by subcutaneous implantation in castrated mice and
in rats and hamsters. It increased the incidence and accelerated the
appearance of mammary tumours in both male and female mice and
produced kidney tumours in hamsters.
Oestriol is embryolethal, especially for preimplantation embryos, in
5.2 Human data
No case reports or epidemiological studies on oestriol alone were
available to the Working Group. Epidemiological studies on steroid
hormones used in oestrogen-progestin oral contraceptive preparations have been summarized
in the section, 'Oestrogens and Progestins in Relation to Human Cancer'.
There is limited evidence for the carcinogenicity of oestriol in
experimental animals. Studies in humans strongly suggest that the
administration of oestrogens is causally related to an increased
incidence of endometrial carcinoma; there is no evidence that oestriol
is different from other oestrogens in this respect.
For definition of the italicized terms, see Preamble Evaluation.
Previous evaluation: Vol. 6 (1974)
Subsequent evaluation: Suppl. 7 (1987) (Steroidal oestrogens)
Last updated: 7 April 1998