New data on management of breast biopsy abnormalities

Volume 3, Issue 2, 2014

Summary

Two types of breast tissue abnormalities may have the same potential to progress to breast cancer, a Mayo Clinic study shows.

Photograph of Lynn C. Hartmann, M.D., an oncologist at the Mayo Clinic Cancer Center

Lynn C. Hartmann, M.D.

Results of a long-term study suggest that two types of breast tissue abnormalities have the same potential to progress to breast cancer, findings that seem to contradict current understanding and that may help better inform women about their follow-up care.

The findings were published online Feb. 6, 2014, in the journal Cancer Prevention Research.

"This study challenges current understanding that atypical ductal hyperplasia (ADH), a type of breast tissue abnormality, leads to breast cancer in the same breast while atypical lobular hyperplasia (ALH), another type of breast tissue abnormality, may not be a direct precursor of breast cancer, but may indicate equal risk of breast cancer across both breasts," said the study's author, Lynn C. Hartmann, M.D., an oncologist at the Mayo Clinic Cancer Center.

"We showed that even though the two types of atypia look different histologically, they behave quite similarly in terms of what happens to patients," she said.

According to Dr. Hartmann, more than 1 million American women have a breast biopsy with benign findings every year.

About 10 percent of these biopsies reveal atypical hyperplasia, a premalignant finding with a proliferation of abnormal cells, which have some features of a breast cancer. There are two types of atypical hyperplasia based on their microscopic appearance — ADH and ALH — and it has been thought that they behave differently. Hyperplasia and atypical hyperplasia are both considered benign breast disease.

Dr. Hartmann and her colleagues identified 698 women from the Mayo Benign Breast Disease Cohort who had biopsy-confirmed atypia. Of these, 330 had ADH, 327 had ALH and 32 had both.

The investigators followed these women for an average of 12.5 years. During that time, 143 of the women developed breast cancer. A similar number of women with either ADH or ALH developed breast cancer in the same breast within five years of atypia diagnosis.

This finding led the authors to suggest that ALH, like ADH, may be a precursor to breast cancer in addition to being a risk indicator.

Contrary to current understanding that ALH might mostly lead to the development of lobular cancer, this study found that ALH predominantly resulted in ductal cancer of the breast, which is a similar outcome as with ADH. Both ADH and ALH resulted in invasive ductal cancers, of which 69 percent were of intermediate or high grade. About 25 percent of these cancers had spread to the lymph nodes. The pattern of cancers in these patients resembled those seen in the general population.

"If a woman has a breast biopsy and if it shows atypia, it might be wise for her to be seen at a breast center for recommendations about surveillance and preventive therapy options," Dr. Hartmann explained. "We hope these data will further help clinicians make informed decisions for breast atypia management strategies."