Correspondence

Breast Cancer and Hormonal Therapy in Postmenopausal Women

N Engl J Med 2009; 360:2366-2367May 28, 2009

Article

To the Editor:

In their article on the Women's Health Initiative (WHI) study of combined hormone therapy, Chlebowski et al. (Feb. 5 issue)1 describe a marked decrease in the risk of breast cancer after the discontinuation of menopausal treatment. Using a similar approach, we investigated whether a decrease in risk was also seen in the French E3N cohort, in which the use of hormone therapy was self-reported biennially.2 Among postmenopausal respondents to the 1997–1998 questionnaire, women receiving combined hormone therapy and those who had never received hormone therapy were followed from January 1999 to the date of diagnosis of any cancer, the last completed questionnaire, or July 2005, whichever occurred first. Hazard ratios for breast cancer among women who received combined hormone therapy, as compared with those who had never received such therapy (in the 1997–1998 period), dropped toward unity after 2002, in parallel with an important reduction in the use of hormone therapy (see Table 1 in the , available with the full text of this letter at NEJM.org). Our results in a French population corroborate the findings of the WHI study.3

Agnès Fournier, Ph.D.
Marie-Christine Boutron-Ruault, M.D., Ph.D.
Françoise Clavel-Chapelon, Ph.D.
INSERM ERI20, F-94805 Villejuif, France

3 References

1. 1

   Chlebowski RT, Kuller LH, Prentice RL, et al. Breast cancer after use of estrogen plus progestin in postmenopausal women. N Engl J Med 2009;360:573-587
   Full Text | Web of Science | Medline

2. 2

   Fournier A, Berrino F, Clavel-Chapelon F. Unequal risks for breast cancer associated with different hormone replacement therapies: results from the E3N cohort study. Breast Cancer Res Treat 2008;107:103-111[Erratum, Breast Cancer Res Treat 2008;107:307-8.]
   CrossRef | Web of Science | Medline

3. 3

   Ringa V, Fournier A. Did the decrease in use of menopausal hormone therapy induce a decrease in the incidence of breast cancer in France (and elsewhere)? Rev Epidemiol Sante Publique 2008;56:297-301
   CrossRef | Web of Science | Medline

Author/Editor Response

We concur with Fournier and colleagues that their year-to-year results regarding the incidence of breast cancer in the French E3N cohort are similar to our findings in the WHI observational study. Their results support the hypothesis that the recent reduction in the incidence of breast cancer in several countries is related to a decrease in the use of combined hormone therapy. In the two cohorts, the hazard ratios were similar (approximately 2) for breast cancer among women who had received estrogen plus progestin for longer intervals. For women who continued to receive combined hormone therapy for longer than about 5 years, the annual risk of breast cancer was doubled with each subsequent year. These results have implications for women who are already receiving combined hormone therapy: there are benefits to stopping and risks to continuing with respect to breast cancer.

Rowan T. Chlebowski, M.D., Ph.D.
Los Angeles Biomedical Research Institute, Torrance, CA 90502
rchlebowski@gmail.com

Ross L. Prentice, Ph.D.
Fred Hutchinson Cancer Research Center, Seattle, WA 98109

Citing Articles (2)

Citing Articles

1. 1

   Jane H. Kass-Wolff, Jennifer E. Fisher. (2011) Menopause and the hormone controversy. The Nurse Practitioner 36:7, 22-29
   CrossRef

2. 2

   L. Daubisse-Marliac, P. Delafosse, J. B. Boitard, F. Poncet, P. Grosclaude, M. Colonna. (2011) Breast cancer incidence and time trend in France from 1990 to 2007: a population-based study from two French cancer registries. Annals of Oncology 22:2, 329-334
   CrossRef