International Agency for Research on Cancer (IARC) - Summaries & Evaluations
OESTRONE AND OESTRONE BENZOATE
VOL.: 21 (1979) (p. 343)
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
Oestrone was tested in mice by oral administration; in mice, rats and
hamsters by subcutaneous injection and implantation; and in mice by
skin painting. Its administration resulted in an increased incidence
of mammary tumours in mice; in pituitary, adrenal and mammary tumours,
as well as bladder tumours in association with stones, in rats; and in
renal tumours in both castrated and intact male hamsters.
Oestrone benzoate increased the incidence of mammary tumours in mice
following its subcutaneous injection.
Oestrone is embryolethal for preimplantation embryos in some species.
5.2 Human data
No case reports or epidemiological studies on oestrone 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 sufficient evidence for the carcinogenicity of oestrone in
experimental animals. In the absence of adequate data in humans, it
is reasonable, for practical purposes, to regard oestrone as if it
presented a carcinogenic risk to humans. 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 oestrone 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