Women whose mammograms reveal a suspicious lesion need a needle biopsy to confirm or rule out cancer. But if that biopsy reveals only abnormal -- not cancerous -- cells, is a more extensive evaluation necessary?
Yes, suggests a new study by doctors at Washington University School of Medicine in St. Louis. They looked at the medical records of women whose initial core-needle breast biopsies found rare, yet benign breast conditions: atypical lobular hyperplasia (ALH) or lobular carcinoma-in-situ (LCIS). These lesions are known to increase a woman's risk of breast cancer, but what the researchers found was surprising.
Follow-up surgical biopsies in which more breast tissue was removed found that up to 25% of the women actually had cancer in addition to their high-risk breast conditions. Most of the cancers were invasive, meaning the tumors had penetrated normal breast tissue and would require treatment. None of the tumors had spread beyond the breast.
"This is very significant," explains lead author Julie A. Margenthaler, M.D., assistant professor of surgery and a breast surgeon at the Siteman Cancer Center at Washington University School of Medicine and Barnes-Jewish Hospital. "We now know that we can't assume that women with ALH or LCIS are cancer free."
The researchers published their study in the October issue of The American Journal of Surgery.
LCIS and ALH are known to increase the risk of breast cancer but neither is considered a precancerous condition. Together, they represent only about one percent of all breast lesions, Margenthaler says. "This seems like a small number but with more than 100,000 core-needle breast biopsies performed in the United States each year, the number of potential cancers missed by not doing a more extensive follow-up biopsy is sizeable."
The study included 35 women who received more extensive surgical biopsies after the initial core-needle biopsies showed LCIS or ALH. Core-needle biopsies are performed with local anesthesia and use a hollow needle to remove several small samples of breast tissue that are then examined under a microscope for tell-tale signs of cancer. If the cells are abnormal, a surgical biopsy can be performed immediately. It involves removing the entire suspicious area, along with some of the surrounding, normal tissue, which leaves a small scar.
In the study, core-needle biopsies found LCIS in 16 patients, and follow-up surgical biopsies detected cancer in four of these women. Of the 19 patients initially diagnosed with ALH, surgical biopsies found that three of them had cancer. All but one of the seven cancers was invasive. The researchers noted no difference between those with cancer and those without in terms of age, number of children, hormonal status or previous breast biopsies - all risk factors for breast cancer.
The cancers detected in the current study are tiny, too small to be felt by a woman or her doctor, says senior author Jill R. Dietz, M.D., assistant professor of surgery and a Washington University breast surgeon. "In patients who were ultimately found to have cancer, it is likely that the core-needle biopsy simply missed the cancer cells and instead extracted the benign cells."
As a comparison, the study also included 61 women whose core-needle biopsies detected a precancerous condition called atypical ductal hyperplasia (ADH). Previous studies have found that many of these women actually have cancer in addition to ADH. Indeed, breast surgeons have for several years routinely recommended that women with ADH routinely undergo more extensive surgical biopsies to look for cancer.
That recommendation was confirmed by the current study. The more extensive surgical biopsies found cancer in 31 percent of the women who were initially diagnosed with ADH from the needle biopsy.
Based on the current study's results, all patients whose initial breast biopsies show LCIS or ALH at Barnes-Jewish Hospital in St. Louis now routinely receive a follow-up surgical biopsy to confirm or rule out cancer. "This is an important shift in the way we approach these patients," Margenthaler says. "In the past, whether women received a more extensive biopsy was often an arbitrary decision, based on the recommendation of the surgeon or the pathologist."
As the number of women getting mammograms continues to increase, and imaging techniques improve, Dietz and Margenthaler say they expect to see a rise in cases of LCIS and ALH. "Knowing that these women should receive more extensive surgical biopsies will have a dramatic effect on our ability to diagnose breast cancer at the earliest stage possible and ensure the women get the treatment they need," Dietz says.
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