Certain types of breast disease may signal risk

New evidence indicates that women with benign breast disease have a higher risk for breast cancer, and that certain types of breast disease may predict the near-term development of breast cancer.1 The new findings may provide a first step in stratifying women with a benign lesion into high- and low-risk groups, states an accompanying editorial to the new research.2

Benign breast disease refers to any lumps or mammographically detected abnormalities that have been biopsied and found to not contain cancerous cells. According to the American Cancer Society, about seven in 10 biopsies done for benign breast conditions do not contain any hyperplasia.3

To conduct the new study, a scientific team examined medical records of 9,087 women diagnosed with benign breast disease in the Mayo Clinic Surgical and Pathology Indices at Rochester, MN, then noted the incidence of breast cancer for a median of 15 years after the initial diagnosis. All benign breast samples were evaluated by a breast pathologist unaware of initial diagnoses or patient outcomes and assigned to one of three categories of benign breast lesions: nonproliferative (no cell overgrowth), proliferative (overgrowth of normal cells), and atypical (overgrowth of abnormal cells). Researchers also asked the women about their family history of breast cancer.

The team identified two risk factors for breast cancer after the diagnosis of benign breast disease: the histologic classification of a benign breast lesion and a family history of breast cancer. Investigators found that women with the most common, nonproliferative forms of benign disease had no increased risk of developing breast cancer, as long as they did not have a strong family history of breast cancer. However, proliferative and atypical lesions pointed to an increased risk of a future breast cancer, even when the family history of breast cancer was negative.1

About two-thirds of the women were found to have nonproliferative growths, which in and of themselves, are not associated with an increased risk of a later breast cancer, explains Lynn Hartmann, MD, an oncologist at the Mayo Clinic School of Medicine in Rochester and lead author of the new research. Another 30% contained excess numbers of normal-appearing cells. These so-called proliferative cells are associated with an approximate two times increased risk of a later breast cancer, she states. The remaining 3%-4% of findings contained excess number of cells that appeared abnormal. Women with these atypia findings have a quadruple increased risk of a later breast cancer, according to Hartmann.

How to explain risks?

When women hear that they are at "increased risk for breast cancer," they can become anxious, says Joann Elmore, MD, MPH, University of Washington School of Medicine in Seattle and co-author of the editorial accompanying the new research.

Even without hearing that "you are at increased risk of breast cancer," most women in the United States overestimate their individual risk of breast cancer, she reports. In addition, many women in the United States have had breast biopsies, and most of these women will have benign breast disease. These are the women who will be told that they are at "increased risk" of breast cancer, Elmore adds.

So how can you talk to women about the new findings? Absolute risk statistics may be more helpful to explaining the results, according to the editorial:

  • Among 100 women with nonproliferative histologic findings, about six women will develop breast cancer.
  • Among 100 women with proliferative disease, the number in whom breast cancer will develop increases from five to about 10.
  • Among 100 women with atypical hyperplasia, about 19 women will develop breast cancer.2

Pay attention to how you "frame" the risks, the editorial suggests. Negative framing, as stated in the absolute risk examples above, may aid in willingness to participate in a treatment or a screening, whereas positive framing may not, the editorial states.2

"Expressing the absolute risk in a positive frame would lead us to say that among 100 women in the general population, breast cancer will not develop in 95 of them within the next 15 years; among 100 women with a biopsy revealing nonproliferative disease, 94 will not receive a diagnosis of breast cancer," the editorial explains.2

(October is National Breast Cancer Awareness Month. Use the resource to prepare your clinic's observance of the event.)

References

  1. Hartmann LC, Sellers TA, Frost MH, et al. Benign breast disease and the risk of breast cancer. N Engl J Med 2005; 353:229-237.
  2. Elmore JG, Gigerenzer G. Benign breast disease — the risks of communicating risk. N Engl J Med 2005; 353:297-299.
  3. American Cancer Society. Benign Breast Conditions. Accessed at: www.cancer.org.