Every cell in your body contains a waxy substance called cholesterol. Cholesterol helps your body make a number of other important substances, including vitamin D and hormones. But too much cholesterol can make it harder for your arteries to carry blood from your heart to the rest of your body. This can increase your risk of heart disease, heart attack and stroke.
You may have heard of “good” or “bad” cholesterol. The bad cholesterol is called low-density lipoprotein (LDL). It can build up in your arteries and stop blood from flowing through your body the way it should. The good cholesterol is called high-density lipoprotein (HDL). It can slow or stop bad cholesterol from building up. Keeping bad cholesterol low is an important part of being healthy.
If you have high cholesterol, you’re not alone. Millions of Americans have too much cholesterol in their blood. Some people are born with a higher risk of developing high cholesterol. Others develop high cholesterol because of smoking, not exercising enough or not eating healthy. Foods that are high in saturated fat, such as many meats, eggs and dairy products, and some baked goods, can raise the amount of cholesterol in your body to an unhealthy level.
But certain breast cancer treatments, called aromatase inhibitors (AIs), can also lead to high cholesterol. If you have hormone receptor-positive breast cancer and are postmenopausal, you may take an AI such as anastrozole (Arimidex), exemestane (Aromasin) or letrozole (Femara). These medicines lower your risk of cancer coming back by lowering the amount of estrogen in your body.
Research shows about 15 to 20 percent of women who take aromatase inhibitors develop high cholesterol. It also suggests women who take aromatase inhibitors for more than 5 years may have a higher risk of high cholesterol than those whose treatment ends earlier. Exemestane may not be as likely to raise cholesterol levels as the other AIs. Ask your doctor why he or she recommends a certain AI and whether it may cause high cholesterol.
Other breast cancer treatments, such as radiation therapy (to the left side of the chest, over the heart) and trastuzumab (Herceptin), a targeted therapy for HER2-positive breast cancer, are known to cause other types of heart problems. Research suggests if you had high cholesterol before you started treatment with these, you could be more at risk for heart problems from those treatments than people with lower cholesterol before treatment.
Exercise and a low-fat, high-fiber diet is recommended to lower cholesterol. But you may also need medicine. Statins are the most common medicine used to treat high cholesterol. By changing the way your liver makes cholesterol, statins can lower your level of bad cholesterol and raise your level of good cholesterol. Statins should be taken once a day by mouth. Atorvastatin (Lipitor) and rosuvastatin (Crestor) are two of the most well-known statins. Cholesterol absorption inhibitors, bile-acid-binding resins and injectable medicines that help the liver absorb more cholesterol are also options for treating high cholesterol. Whether these medicines affect how well cancer treatments work is not known but is a subject of ongoing research.
After prescribing you medicine for high cholesterol, your doctor will order regular blood tests to see how the medicine is working.
High cholesterol doesn’t usually have any symptoms. You need a blood test to find out what your cholesterol levels are. Many doctors give these tests as part of an annual physical exam, but you can ask for one at any time. Your cancer team may also test for cholesterol levels during blood work related to treatment. It’s OK to ask your doctor if they’ve tested your cholesterol level and what they found.
The amount of cholesterol in your body is measured in milligrams of cholesterol per deciliters of blood, written as “mg/dL.” Guidelines recommend that
- Bad cholesterol, or LDL, be under 130 mg/dL
- Good cholesterol, or HDL, be over 40 mg/dL
- Total cholesterol be under 200 mg/dL
Healthcare providers generally recommend everyone get their cholesterol levels checked at least every few years. Ask your team how often they recommend you get tested. They may want to test your blood more often than that while you’re being treated for breast cancer.
You can lower your risk of high cholesterol by
- Eating a low-fat, high-fiber diet
- Maintaining a healthy weight
- Lowering stress
- Not smoking
Your healthcare providers may be able to give you tips or direct you to a nutritionist or other provider who can help you make your lifestyle healthier.