Medicines to Reduce Breast Cancer Risk

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Breast cancer risk assessment

The first step in deciding if you should take a drug to lower your breast cancer risk is to have a health care professional do a breast cancer risk assessment. All drugs have benefits and risks. For women with significant risk of breast cancer, the benefits of chemoprevention often outweigh the risks.

For now, most experts say that a woman’s breast cancer risk should be higher than average for her to consider taking tamoxifen or raloxifene. A woman who is at higher than average breast cancer risk needs to compare the benefit of possibly reducing her breast cancer risk with the risk of side effects and problems from taking one of these drugs.

Your risk factors need to be identified to find out if you are at higher than average risk for breast cancer. A risk factor is anything that is linked to a higher chance of getting a disease. For example, smoking is a known risk factor for lung and many other cancers. But keep in mind that not all risk factors actually play a part in causing the cancer, and some risk factors cannot be changed. Having a higher risk because of a certain risk factor does not mean that you will develop breast cancer. In fact, most women who have one or more risk factors will never develop breast cancer.

Age is the major risk factor for breast cancer. The risk goes up as you get older. If you are 60 years old you have a higher risk of having breast cancer than if you are 40. But older women also seem to have more of the serious side effects of tamoxifen. In studies, the greatest breast cancer risk reduction with the fewest side effects was seen in younger women who were at higher risk for breast cancer. Such women would include those with atypical ductal hyperplasia or those who had a sister or mother with breast cancer. For more, see the section called “Weighing risks versus benefits.”

Another risk factor is family history. If your mother, sister, child, aunt, or grandmother has had breast cancer, or you have a male relative with breast cancer, then you have a higher risk than if you don’t have any close relatives with breast cancer.

Other important risk factors are having a personal history of breast cancer, LCIS (lobular carcinoma in situ), DCIS (ductal carcinoma in situ), ADH (atypical ductal hyperplasia), or a prior breast biopsy. There are other risk factors for breast cancer that are less important, but when they are combined they can influence your risk. Examples of these are age at first menstruation, age at menopause, and age when your first child was born.

Breast cancer risk assessment tools

Researchers have built some statistical models to help predict a woman’s risk of getting breast cancer.

The Gail Model is a tool designed for health professionals. Doctors and nurses can use it to help women make informed decisions about taking a drug to lower the risk of breast cancer. It gives a risk score by calculating a woman’s risk of getting breast cancer in the next 5 years and over her lifetime.

The tool does have some limits, though. For instance, some doctors say it does not count family history enough. It’s also important to note that this tool was created for health professionals, so it uses terms and explanations that patients might not understand. Ask your doctor about using this tool to give you a better idea about your risks and whether you should consider taking medicine to reduce your breast cancer risk.

Other risk tools are based largely on risk factors linked to family history, such as the Tyrer-Cuzick model and the Claus model. These are less available, and are generally used only by professionals to estimate breast cancer risk.

None of these tools is perfect. Each has its strengths and weaknesses, and a woman’s risk result may vary depending on the tool used. Many tools have not been tested on minority women, so they may not work the same for everyone. These tools can give you a rough estimate of risk, but they can’t predict for sure if you will develop breast cancer.


Last Medical Review: 06/04/2013
Last Revised: 07/17/2013