Executive Director: Mrs Jean Wright

PO Box 687, Wray, Lancaster LA2 8WY, UK

Tel: +44 15242 21190 Fax: +44 15242 22596

e-mail: jwright.ims@btopenworld.com

Press Statement

ISSUED ON BEHALF OF THE INTERNATIONAL MENOPAUSE SOCIETY BY

Amos Pines, President, David Sturdee, General Secretary and

Martin Birkhäuser, Treasurer

December 19, 2006

IMS reaction to recent breast cancer data

In the 29th San-Antonio Breast Cancer Symposium, December 14–17, 2007, data from the M.D. Anderson Cancer Center at the University of Texas demonstrated an unexpected sharp decline in the incidence of breast cancer in certain areas in the United States. Overall, the incidence dropped by 8%, whereas for women aged 50–69 years, diagnosed with estrogen receptor (ER)-positive cancer, the drop was 12%. A similar observation of 11% difference in the rate of breast cancer between 2001 and 2003 was reported last month in women aged 50–74 years by the Kaiser Permanente Division of Research and the Northern California Cancer Center1. Both teams speculated that there could be a link with the dramatic decrease in postmenopausal hormone use which occurred after the first release of the Women’s Health Initiative (WHI) data in July 2002. But the investigators were very careful with their suggestion on possible association between discontinuation of hormones and breast cancer: “We can’t say that changes in hormone therapy use caused the decline in breast cancer, because these data don’t link hormone users directly to breast cancer diagnoses” (Dr Lisa Herrinton from Kaiser Permanente’s Division of Research). The media, however, presented those observations in a more definite way: “Big fall in breast cancer cases after women abandon HRT” (Times online, December 15); “Fewer breast cancers linked to less hormone therapy” (Reuters, December 14); “Breast cancer drop tied to hormones” (Yahoo News, December 15).

With all the above information in mind, the International Menopause Society (IMS) wishes to stress the following:

(1) Currently, two parallel trends were observed in the United States – less breast cancer and less hormone use. However, any attempt to link both into one framework is premature and the scientific basis for such an assumption has not been established. Many important factors were not evaluated: the rate of

mammography, the rate of routine visits to the primary physician, the rate ofother risk factors which are relevant to breast cancer risk (smoking, physical activity, medications, e.g. SERMS). It is legitimate to speculate whether many women, after having stopped taking their hormone therapy, also stopped seeing their gynecologist regularly and so omitted their mammography examinations, leading to a decrease in diagnosed breast cancer cases. Furthermore, a careful look at the presented data on breast cancer incidence demonstrates that some decrease in rate was already apparent by 1999–2001, before the WHI scare and the massive abandonment of hormone use.

(2) If the decrease in breast cancer incidence was largely related to hormones, how would one explain the 4% drop in ER-negative cases seen in the above University of Texas study?

(3) Data from other countries are still lacking or inconsistent. “The UK statistics show nothing as dramatic as this”, Professor Valerie Beral, of Cancer Research UK, said. “There had been a slight drop in breast cancer between 2003 and 2004 in women aged 50–64”.

(4) Current knowledge of the biology and development of breast cancer points at the unlikelihood of a 10% drop in breast cancer incidence occurring within a year after cessation of estrogen therapy. The Nurses’ Health Study reported in 1995 that the risk of breast cancer for women stopping hormone therapy equalled that of non-users within 2 years after cessation2. However, analysis of a subgroup of women who stopped taking hormones after 5 or more years of use showed that the adjusted relative risk remained high at 1.44 during the first 2 years, but declined later on in years 2–4. Based on the above, the IMS calls the medical community, the media, and the public to be very cautious when interpreting the new data on trends in breast cancer incidence in the United States. It is certainly a very positive sign, which should be followed carefully, but has little to do with the well-established data on breast cancer risk and hormone therapy that were collected in the WHI study. During a mean follow-up of 5.2 years, the added absolute risk for invasive breast cancer in the conjugated equine estrogen (CEE) plus medroxyprogesterone acetate arm was of the order of less than one case per 1000 women-years3. There was no risk for women who never used hormones prior to the study and in those aged less than 60 years. Fewer cases of invasive breast cancer were actually seen in the CEE-only arm of the WHI study during 6.8 years of follow-up4. The IMS maintains its recommendation that hormone therapy should be prescribed whenever indicated. The use of hormones in early menopause and up to age 60 years has a very minor potential for harm, but may carry substantial benefits. Women should decide annually if they wish to continue with treatment after consultation with their caregivers.

References

1. Clarke GA, Glaser SL, Uratsu CS, et al. Recent declines in hormone therapy utilization and breast

cancer incidence: clinical and population-based evidence. J Clin Oncol 2006;24:e49–50

2. Colditz GA, Hankinson SE, Hunter DJ, et al. The use of estrogens and progestins and the risk of

breast cancer in postmenopausal women. N Engl J Med 1995;332:1589–93

3. Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in

healthy postmenopausal women: principal results from the Women's Health Initiative randomized

controlled trial. JAMA 2002;288:321–33

4. Stefanick ML, Anderson GL, Margolis KL, et al. Effects of conjugated equine estrogens on breast

cancer and mammography screening in postmenopausal women with hysterectomy. JAMA

2006;295:1647–57