By Gene Emery
(Reuters Health) - A type of "benign" mass found in the breast tissue of about 100,000 U.S. women each year poses a greater risk of cancer than previously thought, according to a new review.
The mass is classified as atypical hyperplasia, or atypia. Most women who have it - and one out of 10 women who have a breast biopsy do - are usually told that their test result was benign, even though their cells seemed to be exhibiting some early characteristics of a tumor.
Doctors may tell those women that they face an above-average risk of cancer so they need to be followed more closely, a recommendation based on the fact that such women are four or five times more likely to develop breast cancer. But that statistic isn't meaningful for a woman who doesn't know what the normal risk is.
Researchers have now cast that risk in more concrete terms in the January 1 issue of the New England Journal of Medicine.
Women with atypia, they found, have a 7 percent risk of developing a tumor with five years after the biopsy, a 13 percent risk after 10 years and a 30 percent risk after 25 years.
Researchers at Vanderbilt University have found a similar risk level.
"It gives you the scale of the risk" and it turns out to be a bit higher than the estimated risk that comes from some popular methods used to try to predict a woman's likelihood of developing breast cancer, said Dr. Lynn Hartmann of the Mayo Clinic in Rochester, Minnesota, who led the review.
The findings should change the way women with atypia are treated, leading to more-aggressive screening using MRI and more emphasis on using drugs that have actually been shown to prevent breast cancer, she told Reuters Health.
The American Cancer Society (ACS) has said that an MRI scan is worthwhile for women whose lifetime risk of breast cancer is 20 to 25 percent, Hartmann said.
"But they didn't feel that women with atypical hyperplasia met that risk." Based on this new analysis, they do.
"They've got a legitimate point," said Dr. Otis Brawley, chief medical officer of the ACS, who was not connected with the research. Women with atypia probably should be getting an MRI instead of a conventional mammogram. In addition, cancer prevention with drugs such as tamoxifen or raloxifene should be an option, he said.
For example, with raloxifene, "We've done the science. We've proven that it lowers the risk for women at high risk and I don't understand why more people won't take it," Brawley said. "We have a large number of women who are undergoing the surgical removal of both breasts to reduce their risk of breast cancer, yet we have a pill with very few side effects that can prevent cancer and people are passing it up."
It's not clear how many women who have had a "benign" biopsy have been told they have atypical hyperplasia.
Hartmann said if a patient has been told she had "some early abnormal cells" or "abnormal cells" or "atypical cells that are benign," she might want to contact her doctor to weigh her options.
"We're not saying every woman who has ever had a biopsy should try to track it back because 90 percent of the time the woman won't have atypia," she said. "But if there was any question at the time when she had a conversation, she might want to clarify it further."
"Go talk to your internist who did the referral," Brawley said. "That's someone with whom you should have an open and honest conversation about this. You should be getting, at the absolute minimum, a high-quality mammogram every year with a radiologist who is aware of the previous diagnosis. She should perhaps consider getting an MRI screening."
He cautioned, however, that there is still no hard evidence that being more aggressive in looking for breast cancer in women with atypia will actually prevent deaths, but "I still want to do it because it think we probably do save lives."
Hartmann said many women with atypia are not getting drugs like tamoxifen because of the risk of side effects. But the new analysis of previous research shows that when you compare side effect rates of women getting the drug and the rates with placebo, "the number of serious side effects is very low."
She said post-menopausal women also have the option of taking an aromatase inhibitor such as anastrozole.
SOURCE: http://bit.ly/1Ah5uJv New England Journal of Medicine, online December 31, 2014.