Breast biopsy: Interpreting your risk of breast cancer

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Breast biopsy: Interpreting your risk of breast cancer

Benign breast disease can increase your risk of breast cancer.

You remember how relieved you were when told that your breast biopsy was benign — that it showed no signs of cancer. You didn't have breast cancer, but the irregular mammogram results and the need for a biopsy gave you quite a scare.

Though doctors have known that a benign reading from a biopsy (benign breast disease) might mean an increased risk of a later breast cancer, they now have a better idea of how much that benign finding influences your risk, thanks to a new study of benign breast disease.

The good news: The majority of women with benign breast disease don't face an increased risk of breast cancer. And those with the types of benign breast disease that do increase their risk of breast cancer might not have as high a risk as was previously thought.

What is benign breast disease?

Women who've had a breast biopsy with benign findings have so-called "benign breast disease." Breast biopsies are done when a suspicious lump or area of thickening within the breast is discovered on examination, or because an abnormality is detected on a mammogram. As the name implies, benign breast disease is benign — it's not cancerous. Benign breast disease is common — each year, about 1 million U.S. women are found to have benign breast disease.

Some doctors prefer to refer to benign breast disease as benign breast conditions or changes, rather than disease. The word "disease" can sound intimidating and might make you think there's something seriously wrong with you.

Researchers aren't sure whether some forms of benign breast disease represent a very early form of cancer. It could be that some types of benign breast disease are actually precursors of cancer. It could also be that benign breast disease is simply a risk indicator — a sign that a woman may be at higher risk of cancer in the future.

"Benign breast disease could indicate what's going on in a woman's breast tissue genetically and hormonally," says Lynn Hartmann, M.D., a cancer specialist at Mayo Clinic, Rochester, Minn., and lead author of the new study of benign breast disease and its association with breast cancer risk. Future research will explore this question to better define benign breast disease's possible roll in breast cancer development.

How do you know if you have benign breast disease?

You won't know if you have benign breast disease until the suspicious lump or mass in your breast is biopsied. A biopsy is a surgical procedure to remove a sample of cells from your breast to test for the presence of cancer.

Benign breast disease is usually divided into three categories, based on the appearance of the cells under a microscope: nonproliferative, proliferative without atypia and atypia.

Type of benign breast disease What is it? Examples
Nonproliferative Changes within the breast, such as an increase in fibrous tissue. Cysts, ductal ectasia, simple fibroadenoma, Mondor's disease, mastitis, galactocele, panniculitis, hamartoma
Proliferative without atypia Excessive cell growth, especially of the duct linings, but no cells that could be considered precancerous. Cells show few genetic changes. Ductal hyperplasia that is greater than mild, sclerosing adenosis, papilloma, complex fibroadenomas
Atypia Excessive cell growth with some cells considered atypical, meaning they have some but not all features of cancerous cells. Cells show genetic changes that could make them potentially invasive. Atypical ductal hyperplasia and atypical lobular hyperplasia

How does benign breast disease affect your risk of breast cancer?

First, know that your risk of breast cancer is simply an estimate of the number of women with findings similar to your situation who will eventually develop cancer. Risk doesn't mean that you'll definitely get breast cancer. Some women thought to be at low risk of cancer will develop cancer, and some women with a high risk of cancer never develop cancer. Though the numbers can be alarming, know that the risk numbers are only an estimate of risk — not your exact chances of getting breast cancer.

 

Average risk of breast cancer among study participants
Condition Number of breast cancer cases in next 15 years
Breast cancer incidence in the study control group 5 of every 100 women
Nonproliferative 6 of every 100 women with nonproliferative disease
Proliferative without atypia 10 of every 100 women with proliferative disease without atypia
Atypia 19 of every 100 women with atypia

 

If you've had nonproliferative benign breast disease
In general, these common changes in the breast don't increase your risk of breast cancer in the future. However, if you have a strong family history of breast cancer, your risk of breast cancer is higher than that of a woman without a family history. Ask your doctor about how your family history affects your risk.

Risk of cancer with nonproliferative benign breast disease

Illustration of risk of breast cancer in women with nonproliferative benign breast disease

To help you better understand how a benign biopsy affects your risk of breast cancer, imagine that these 100 dots are women who've had a biopsy that determined they had nonproliferative benign breast disease, and they have no family history of breast cancer. Over the next 15 years, six of these women will develop breast cancer. This risk is about the same as the risk of breast cancer in women who have never had a breast biopsy.

Risk of cancer with proliferative benign breast disease without atypia

Illustration of risk of breast cancer in women with proliferative benign breast disease without atypia

To help you better understand how a benign biopsy affects your risk of breast cancer, imagine that these 100 dots are women who've had a biopsy that determined they had proliferative benign breast disease without atypia. Over the next 15 years, 10 of these women will develop breast cancer.

Risk of cancer with atypia

Illustration of risk of breast cancer in women with atypia

To help you better understand how a benign biopsy affects your risk of breast cancer, imagine that these 100 dots are women who've had a biopsy that determined they had atypia. Over the next 15 years, 19 of these women will develop breast cancer.

Does a family history of breast cancer raise your risk of breast cancer even more?

That depends on the type of benign breast disease you have and the strength of your family's history of breast cancer. For women with nonproliferative benign breast disease, the risk of breast cancer wasn't increased for study participants with a weak family history of breast cancer. A weak family history of breast cancer means you have at least one woman anywhere in your family diagnosed with breast cancer at any age. However, a strong family history of breast cancer — defined in this study as having either a woman in your immediate family, such as your mother, sister or daughter, diagnosed with breast cancer before the age of 50 or two or more close relatives diagnosed at any age — does increase your risk of breast cancer if you have nonproliferative benign breast disease.

In women who have proliferative disease without atypia and in women who have atypia, the risk of breast cancer is increased regardless of type of family history of breast cancer. In other words, the presence of a positive family history of breast cancer doesn't increase your risk any further, beyond the risk associated with having proliferative disease with or without atypia.

Does your age raise your risk of breast cancer even more?

If you have nonproliferative benign breast disease, being a certain age won't increase or decrease your risk of breast cancer.

However, age does factor in when you have proliferative benign breast disease with or without atypical cells. If you're younger than 45, your risk of breast cancer is higher than that of women over the age of 55. It isn't clear why the risk is higher for younger women.

How long does the increase in breast cancer risk last?

It was previously believed that the increased risk in women with benign breast disease lasted for about 10 years after the breast biopsy, but older studies didn't follow participants for sufficiently long periods of time. The recent study showed that the increased risk appears to persist for a much longer period of time. "In those women with an increased risk, that risk is still elevated even out to 30 years," Dr. Hartmann says.

If you've had a breast biopsy but don't know what type of benign breast disease you have, what should you do?

If you aren't sure what type of benign breast disease you have, ask your doctor whether your previous biopsy contained any atypical cells (atypia). "That's the most important thing — was there atypia?" Dr. Hartmann says. "Atypia puts a woman in another risk category. Most would consider her at high risk."

Dr. Hartmann says that over the past 10 years there's been an increased awareness among doctors of the role atypia plays in the risk of future breast cancer. So women who've had biopsies over the last several years most likely know if they had atypical cells.

What should you do if you think you have an increased risk of breast cancer?

Discuss your risk of breast cancer with your doctor. If you have nonproliferative benign breast disease but no other risk factors for breast cancer, such as a family history of breast cancer, your risk isn't increased. Your doctor will likely recommend that you follow normal breast cancer screening guidelines. These include clinical breast exams and mammography.

If your only risk factor for breast cancer is proliferative benign breast disease without atypia, then your doctor will likely also recommend regular clinical breast exams and yearly mammograms. But if you have other risk factors for breast cancer, such as a strong family history of the disease, your doctor might discuss other options for you, such as participation in clinical trials of medications to prevent breast cancer or clinical trials of new ways to screen for breast cancer. Another option might be medications, such as tamoxifen, that are approved for women with a high risk of breast cancer.

Women with atypia are considered at high risk of breast cancer. You and your doctor should discuss what options you have to reduce your risk of breast cancer. Options include:

  • Medications, such as tamoxifen
  • Vigilant breast cancer screening
  • Clinical trials of breast cancer prevention for high-risk women

Weigh the benefits and risks of each type of risk reduction to help you and your doctor decide what measure, if any, is best for you.

Last Updated: 08/05/2005
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