International Agency for Research on Cancer (IARC) - Summaries & Evaluations
TESTOSTERONE, TESTOSTERONE OENANTHATE
AND TESTOSTERONE PROPIONATE
VOL.: 21 (1979) (p. 519)
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
Testosterone and its esters were tested in mice, rats and hamsters, by
subcutaneous injection and/or implantation, and in rabbits by
Testosterone propionate implanted subcutaneously in mice induced
cervical-uterine tumours, which metastasized in some cases; in rats,
metastasizing prostatic adenocarcinomas were induced in males.
Neonatal treatment of female mice by subcutaneous injection of
testosterone induced lesions of the genital tract and increased the
mammary tumour incidence when the animals were adult. 5b-Dihydrotestosterone, which is considered to be hormonally
inactive in adults, also increased the incidence of mammary
tumours in mice when given neonatally by subcutaneous injection.
Testosterone is embryolethal in pre- and postimplantation embryos and
causes virilization in female offspring.
5.2 Human data
No case reports or epidemiological studies on testosterone alone were
available to the Working Group. There are limited data concerning the
possible long-term effects of androgenic-anabolic steroids, which are related to testosterone. An association between
these synthetic androgenic steroids and the occurrence of
hepatocellular carcinomas has been suggested, but the evidence is
There is sufficient evidence for the carcinogenicity of testosterone
in experimental animals. In the absence of adequate data in humans, it
is reasonable, for practical purposes, to regard testosterone as if it
presented a carcinogenic risk to humans. The only related data in
humans, although insufficient for an evaluation, concern the possible
long-term effects of androgenic anabolic-steroids.
For definition of the italicized terms, see Preamble Evaluation.
Subsequent evaluation: Vol. 6 (1974)
Subsequent evaluation: Suppl. 7 (1987) (Androgenic (anabolic) steroids)
Last updated: 7 April 1998