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As HRT use declines, atypical ductal hyperplasia rates also fall

Last Updated: 2009-11-09 16:52:01 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Reductions in the use of postmenopausal hormone therapy may be one reason why the incidence of atypical ductal hyperplasia (ADH) has been declining in recent years.

The decrease in ADH was a surprise, according to study co-author Dr. Karla Kerlikowske from the San Francisco Veterans Affairs Medical Center. She said in a statement, "We didn't expect to see (a decline) with the increased use of mammography to identify abnormal lesions." Nor, she added, did they expect "a decline in rate of ADH with a decline in postmenopausal hormone treatment use."

In the November issue of Cancer Epidemiology, Biomarkers and Prevention, Dr. Kerlikowske and colleagues explain that they analyzed risk factors and rates of ADH over time using Breast Cancer Surveillance Consortium registry data on nearly 2.5 million screening mammograms done from 1996 to 2005. All subjects were at least 40 years old (mean age, 57.5 years), and none had a history of breast cancer or breast augmentation. The registry included information on breast cancer risk factors, including use of hormone replacement therapy (HRT).

Overall, 1.3% of mammograms resulted in recommendations for biopsy. Out of 30,953 biopsies, 1064 (3.4%) showed pure ADH, 833 (2.7%) showed cancer with ADH in the same breast, and 8,161 (26.4%) showed cancer with no ADH.

The rate of ADH without concurrent breast cancer per 10,000 mammograms peaked in 1999 at 5.5, dropping to 4.4 in 2002 and to 2.4 in 2005, according to the authors.

Similarly, HRT use fell from 35% in 1999-2000 to 11% in 2005, according to the article.

Independent risk factors for both ADH and cancer associated with ADH were a positive family history of breast cancer and current HRT use.

The researchers also report that ADH-associated cancers were more likely to be ductal carcinoma in situ (odds ratio 3.05), and invasive ADH-associated cancers were more likely to be stage I. Cancers with ADH were also more likely to be low grade and estrogen- and progesterone-receptor positive.

"These findings support the theory of separate pathways for low-grade and high-grade breast cancers, with ADH possibly being a precursor of some low-grade cancers," the research team concludes.

Cancer Epidemiol Biomarkers Prev 2009;18:2822-2828.

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