Viele Frauen, die über einen längeren Zeitraum eine Anti-Babypille einnehmen machen sich große Sorgen über das Nebenwirkungsrisiko. Jetzt zeigte eine große US-Studie, dass es keinen ursächlichen Zusammenhang zwischen der Langzeiteinnahme der oralen Kontrazeptiva und dem beobachteten Brustkrebsrisiko gibt.

BMJ 2002;325:8 ( 6 July )

NEJM Volume 346:2025-2032, June 27, 2002, Number 26


Oral Contraceptives and the Risk of Breast Cancer

Polly A. Marchbanks, Ph.D., Jill A. McDonald, Ph.D., Hoyt G. Wilson, Ph.D., Suzanne G. Folger, Ph.D., Michele G. Mandel, B.A., Janet R. Daling, Ph.D., Leslie Bernstein, Ph.D., Kathleen E. Malone, Ph.D., Giske Ursin, M.D., Ph.D., Brian L. Strom, M.D., M.P.H., Sandra A. Norman, Ph.D., Phyllis A. Wingo, Ph.D., Ronald T. Burkman, M.D., Jesse A. Berlin, Sc.D., Michael S. Simon, M.D., M.P.H., Robert Spirtas, Dr.P.H., and Linda K. Weiss, Ph.D.

ABSTRACT

Background It is uncertain whether the use of an oral contraceptive increases the risk of breast cancer later in life, when the incidence of breast cancer is increased. We conducted a population-based, case–control study to determine the risk of breast cancer among former and current users of oral contraceptives.

Methods We interviewed women who were 35 to 64 years old. A total of 4575 women with breast cancer and 4682 controls were interviewed. Conditional logistic regression was used to calculate odds ratios as estimates of the relative risk (incidence-density ratios) of breast cancer.

Results The relative risk was 1.0 (95 percent confidence interval, 0.8 to 1.3) for women who were currently using oral contraceptives and 0.9 (95 percent confidence interval, 0.8 to 1.0) for those who had previously used them. The relative risk did not increase consistently with longer periods of
use or with higher doses of estrogen. The results were similar among white and black women. Use of oral contraceptives by women with a family history of breast cancer was not associated with an increased risk of breast cancer, nor was the initiation of oral-contraceptive use at a young age.

Conclusions Among women from 35 to 64 years of age, current or former oral-contraceptive use was not associated with a significantly increased risk of breast cancer.


Source Information

From the Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta (P.A.M., J.A.M., H.G.W., S.G.F., M.G.M.); the Fred Hutchinson Cancer Research
Center, Seattle (J.R.D., K.E.M.); the Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles (L.B., G.U.); the Center for
Clinical Epidemiology and Biostatistics and the Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia (B.L.S., S.A.N.); and the Division of
Epidemiology, Karmanos Cancer Institute, Wayne State University, Detroit (L.K.W.).

Other authors were Phyllis A. Wingo, Ph.D., Department of Epidemiology and Surveillance Research, American Cancer Society, Atlanta; Ronald T. Burkman, M.D., Department of Obstetrics and Gynecology, Bay State Medical Center, Springfield, Mass.; Jesse A. Berlin, Sc.D., Center for Clinical Epidemiology and Biostatistics and Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia; Michael S. Simon, M.D., M.P.H., Division of Hematology and Oncology, Karmanos Cancer Institute, Wayne State University, Detroit; and Robert Spirtas, Dr.P.H., Contraception and Reproductive Health Branch, Center for Population Research, National Institute of Child Health and Human Development, Bethesda, Md.

NEJM Volume 346:2025-2032

^*****

News roundup

New study adds to evidence that taking oral contraception does not increase risk
of breast cancer

Scott Gottlieb New York

A new study shows that older women who have used oral contraceptives are no more likely to develop breast cancer than those who have not, bolstering a growing body of evidence that no link exists.

But researchers cautioned that the new findings were limited to the age group studied and that more research was warranted for younger women.

The study looked at nearly 9300 women aged 35 to 64. About half of the women had developed breast cancer in the middle to late 1990s. The rest were healthy controls.

Interviews with the women showed that similar proportions of these two groups had used contraceptives (79% of the group without cancer, 77% of the group with cancer). The relative risk was 1.0 (95% confidence interval 0.8 to 1.3) for women who were currently using oral contraceptives and 0.9 (0.8 to 1.0) for those who had previously used them.

The risk did not increase with longer periods of use or with higher doses of oestrogen, and the results were similar among white and black women, among women with a family
history of breast cancer, and among those who had begun using oral contraception at a young age (New England Journal and Medicine 2002;346:2025-32).

The exception to these findings was among women aged 45 to 64 who were taking the pill to alleviate symptoms of menopause or to reduce their risk of ovarian and endometrial
cancer and benign breast disease. The team found a slightly increased risk of breast cancer among these women, but the number of women studied in this group was too small to be significant.

The study focused on older women because of the higher incidence of breast cancer in that age group. The findings essentially matched the results of a major study in 1986 that also
showed no association between oral contraceptives and breast cancer.

"We conducted the study to resolve the longstanding concern," said Dr Robert Spirtas, chief of the National Institute of Child Health and Human Development’s Contraception and
Reproductive Health branch and one of the authors of the study. "Our study provides yet more scientific proof that there isn’t an association."

In an accompanying editorial, Dr Kathy Helzlsouer and Dr Nancy Davidson of Johns Hopkins University write that "for most women, the benefits of avoiding pregnancy, with its
attendant health risks, clearly outweigh these side effects."

But they noted that oral contraceptives could also have other adverse effects, including pulmonary embolism, strokes, liver cancer, and, among smokers who are over age 35, heart problems. Women who have a positive test result for the human papillomavirus are also at increased risk of cervical cancer.
                

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