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

(Group 3)

For definition of Groups, see Preamble Evaluation.

Supplement 7: (1987) (p. 172)

CAS No.: 58-22-0
Chem. Abstr. Name: 2-[4-(2-Chloro-1,2-diphenylethenyl)phenoxy]-N,N-diethylethanamine

Clomiphene citrate
CAS No.: 50-41-9
Chem. Abstr. Name: 2-[4-(2-Chloro-1,2-diphenylethenyl)phenoxy]-N,N-diethylethanamine-
2-hydroxy-1,2,3-propanetricarboxylate (1:1)

A. Evidence for carcinogenicity to humans (inadequate)

Only case reports of benign and malignant tumours occurring at various sites are available [ref: 1-5]. These include testicular tumours in three young men who had received clomiphene as part of hormonal treatment for oligospermia [ref: 2], a hepatoblastoma in a female infant whose mother had received clomiphene citrate as treatment for infertility [ref: 3], a liver-cell adenoma in a woman who had received clomiphene citrate for oligomenorrhoea [ref: 4], and unilateral testicular neoplasms in two of 650 oligospermic men who had received monthly treatments with clomiphene citrate (daily for three weeks followed by a week of rest) for six to 12 months [ref: 5].

B. Evidence for carcinogenicity to animals (inadequate)

Clomiphene citrate was tested in an inadequate experiment in newborn rats by single subcutaneous injection; reproductive-tract abnormalities, including uterine and ovarian tumours, were reported [ref: 1].

C. Other relevant data

No data were available on the genetic and related effects of clomiphene citrate in humans. It did not induce chromosomal aberrations or micronuclei in bone-marrow cells of mice treated in vivo [ref: 6].

Overall evaluation

Clomiphene citrate is not classifiable as to its carcinogenicity to humans (Group 3).

For definition of the italicized terms, see Preamble Evaluation.

Also see previous evaluation: Vol. 21 (1979)


1. IARC Monographs, 21, 551-561

2. Neoptolemos, J.P., Locke, T.J. & Fossard, D.P. (1981) Testicular tumour associated with hormonal treatment for oligospermia. Lancet, ii, 754

3. Melamed, I., Bujanover, Y., Hammer, J. & Spirer, Z. (1982) Hepatoblastoma in an infant born to a mother after hormonal treatment for steriligy. New Engl. J. Med., 307, 820

4. Carrasco, D., Barrachina, M., Prieto, M. & Berenguer, J. (1983) Clomiphene citrate and liver cell adenoma. New Engl. J. Med., 310, 1120-1121

5. Nilsson, A. & Nilsson, S. (1985) Testicular germ cell tumors after clomiphene therapy for subfertility. J. Urol., 134, 560-562

6. IARC Monographs, Suppl. 6, 184-185, 1987

Synonyms for Clomiphene Synonyms for Clomiphene citrate

Last updated: 9 March 1998

    See Also:
       Toxicological Abbreviations