Two types of breast tissue abnormality may have the same potential of progressing to breast cancer, contrary to current belief, according to a new study.
One abnormal tissue finding is known as “atypical ductal hyperplasia” (ADH), an accumulation of abnormal cells in a breast duct. The other abnormal finding is “atypical lobular hyperplasia” (ALH), an accumulation of abnormal cells in a lobule, a small part of a breast lobe that makes milk.
Previously, many experts believed that ADH leads to low-grade ductal breast cancer in the same breast where the biopsy was done, and so it requires complete surgical excision. Meanwhile, many believed that ALH was simply an indicator of increased risk of breast cancer later in both breasts, so it did not require complete surgical removal but perhaps just closer monitoring.
The new research challenges that thinking, suggesting that the two types of abnormalities actually behave in similar ways.
“We were not so sure what to do with ALH before,” said study researcher Dr. Lynn Hartmann, a professor of oncology at the Mayo Clinic, in Rochester, Minn. “This is suggesting, treat it the same as ADH. What we are saying is, it doesn’t matter which kind [of abnormality].”
The study is published in the February issue of Cancer Prevention Research.
In the study, Hartmann’s team identified nearly 700 women (from a larger group of Mayo patients who’d undergone breast biopsies) who had confirmed abnormal cells but no cancer. While 330 of them had ADH, 327 women had ALH and 32 had both.
Hartmann followed the women for an average of 12.5 years. During that time, 143 developed breast cancer.
A similar number of women with either abnormality developed breast cancer in the same breast within five years, the study found. That suggests that ALH may be both a precursor to cancer and an indicator of increased risk, Hartmann said. While some experts believed ALH mostly would lead to lobular cancer, the study found it actually resulted in more ductal cancers, which is how ADH sometimes behaves.
Read more at: MedlinePlus