Two types of breast tissue abnormalities equally likely to progress to cancer
Both atypical ductal hyperplasia and atypical lobular hyperplasia should be considered premalignant lesions with equal potential of progression to breast cancer, according to study results.
The findings contradict the current clinical understanding, which holds that atypical ductal hyperplasia is not a direct antecedent of breast cancer.
Lynn C. Hartmann
“More than a million American women have a breast biopsy with benign findings every year,” Lynn C. Hartmann, MD, professor of oncology at the Mayo Clinic in Rochester, Minn., said in a press release. “About 10% of these biopsies reveal atypical hyperplasia, a premalignant finding with a proliferation of abnormal cells, which have some but not all the features of a breast cancer.”
Researchers evaluated 698 women who underwent breast biopsies at Mayo Clinic whose histologic findings indicated atypical hyperplasia.
The researchers followed all atypical ductal hyperplasia and atypical lobular hyperplasia patients for a mean of 12.5 years. Researchers used the Mayo medical record, Mayo Tumor Registry and a study-related questionnaire to follow patients for breast cancer events and risk factor information. When breast cancers were diagnosed, medical records and tissue slides were acquired for analysis.
Laterality of diagnosed cancers in relation to atypias was categorized as ipsilateral, contralateral and bilateral. Of the 698 women with atypical hyperplasia, 143 developed breast cancer during follow-up.
For both ductal hyperplasia and lobular hyperplasia, there was a 2:1 ratio of ipsilateral to contralateral breast cancer. This prevalence of ipsilateral progression was marked within the first 5 years, a finding which is consistent with a precursor phenotype for ductal hyperplasia and lobular hyperplasia. For both types of atypia, a prevalence of invasive ductal cancers was observed, with 69% of these found to be moderate or high grade.
“Most have considered [atypical ductal hyperplasia] a direct precursor to breast cancer, arguing that it requires complete surgical excision while others have maintained that [atypical lobular hyperplasia] serves as an indicator of heightened and equal risk of breast cancer across both breasts and does not need complete surgical removal,”Hartmann said.
“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. We hope these data will further help clinicians make informed decisions for breast atypia management strategies,” she said.
Disclosure: One researcher reports a commercial research grant as well as consultant/advisory board relationships with Pﬁzer.