Correspondence

Hormonal Contraception

N Engl J Med 1993; 329:1501-1502November 11, 1993

Article

To the Editor:

In their review of hormonal contraception (May 27 issue), Baird and Glasier state, “After differences in sexual activity and the use of barrier methods of contraception (which have a protective effect) have been accounted for, there appears to be no increase in the risk of cervical cancer among women who take a combined oral contraceptive”1.

Most of the case-control studies of cervical cancer reviewed in a recent report by the World Health Organization found the risks to be higher among long-term users of oral contraceptives, even after adjustment for socioeconomic status, sexual behavior, and screening history2. In addition, in the cohort study cited by Baird and Glasier,3 there was a statistically significant trend for the risk of invasive cervical cancer to increase with the duration of oral-contraceptive use. The incidence of cervical cancer was more than four times higher in women who had used an oral contraceptive for 10 or more years than in those who had never used an oral contraceptive. The exclusion of women reporting the use of barrier methods did not materially change the results.

Hormones are generally considered to promote rather than initiate tumor growth. Several hypotheses have been proposed to explain the biologic mechanisms by which oral contraceptives may influence malignant changes of the cervix2. It is therefore too early to exclude oral contraceptives as an independent risk factor for these cancers.

Jose Eluf-Neto, M.D.
Margaret Booth, Ph.D.
London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom

3 References

1
Baird DT, Glasier AF. Hormonal contraception. N Engl J Med 1993;328:1543-1549
Full Text | Web of Science | Medline

2
World Health Organization. Oral contraceptives and neoplasia. World Health Organ Tech Rep Ser 1992;817:1-46
Medline

3
Beral V, Hannaford P, Kay C. Oral contraceptive use and malignancies of the genital tract: results from The Royal College of General Practitioners' Oral Contraception Study. Lancet 1988;2:1331-1335
CrossRef | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: An excess incidence of and mortality from cervical cancer in women taking oral contraceptives has been noted in some studies1,2. The excess exists even after adjustment for socioeconomic status, screening history, smoking, age, and parity in both a retrospective and a cohort study1,2. In the latter, although a history of sexually transmitted disease was documented, there was no information about age at first intercourse or number of sexual partners -- both strongly associated with the incidence of carcinoma of the cervix3. Since the combined oral contraceptive is widely used by young women, it is possible that they have a higher level of sexual activity and a larger number of partners than women who have never used oral contraceptives. Clarification of the relation between oral-contraceptive use and the incidence of cervical cancer will require prospective studies in which sexual activity is carefully recorded.

David T. Baird
Anna Glasier
University of Edinburgh, Edinburgh EH3 9EW, Scotland

3 References

1
World Health Organization. Oral contraceptives and neoplasia. World Health Organ Tech Rep Ser 1992;817:1-46
Medline

2
Beral V, Hannaford P, Kay C. Oral contraceptive use and malignancies of the genital tract: results from The Royal College of General Practitioners' Oral Contraception Study. Lancet 1988;2:1331-1335
CrossRef | Web of Science | Medline