Spotlight On: Breast Cancer and Heart Disease

I've heard that some breast cancer drugs increase my risk for heart disease. Is this true?

Donna White, a UVA pharmacist with the Club Red Clinic answers this month's question about the relationship between heart disease and breast cancer medication. The bottom line - the benefits of breast cancer treatment often outweigh the risks associated with the medication.

Treatment for early breast cancer may increase risk for cardiovascular disease (CVD). However, it is difficult to tease out the risks associated with breast cancer treatment. For instance, breast cancer treatments and early detection have resulted in patients living longer so many survivors are now reaching an age where their risk for heart problems naturally increases. 

Which breast cancer drugs can increase the risk of heart disease?  

There are several therapies for treating breast cancer. Some may have long-term effects on heart health, while others may have only a short-term effect, resolving at the end of treatment. 

Chemotherapy for breast cancer has been associated with cardiovascular complications. Some have been linked to changes in the heart that may lead to heart failure. Many factors will have an impact on the development of CVD, including cumulative dose, age of patient, other drug therapies, the route of drug administration and schedule, and whether or not a patient requires radiation. 

Tamoxifen is an endocrine therapy that stops the growth of breast tumors by competing for estrogen at receptor sites. It’s often used for prevention of recurring breast cancer. Tamoxifen has not been clearly associated with CVD and may improve some lipids such as a decline in LDL (bad cholesterol) and total cholesterol and an increase in HDL (good cholesterol). There have been reports of increased triglycerides and there is an association with increased risk of blood clots; however, tamoxifen use greatly improves breast cancer survival. 

Aromatase inhibitors such as anastrazole or letrozole block an enzyme that is responsible for the production of estrogen. These inhibitors may slightly increase lipids and have been associated with some CVD, but have less association with blood clots. Letrozole may be used after tamoxifen therapy. 

HER-2 therapy or trastuzumab also improves overall survival, but has been linked to cardiovascular disease, in particular heart failure. These drugs work best in breast cancers that have too much protein called HER-2. 

Bevacizumab disrupts the cancer cell and has been linked to cardiovascular disease and high blood pressure. 

How much is my risk increased?  

Overall, the increased risk is small compared to the benefits of breast cancer treatment and depends on other risk factors and which treatment you and your oncologist choose. Most potential side effects are reversible after treatment. Your physicians will monitor your overall health, including your heart, carefully and frequently. 

Is there anything I can do to protect my heart if I am going through treatment for breast cancer?  

Follow nutritional guidelines recommended by your cancer and heart specialist. You may need to take a statin drug to lower cholesterol or other drugs to help keep your heart function strong during treatment. 

If I am already at risk for heart disease, are there other medications I should consider?  

Breast cancer treatments are very specific based on the type and stage of cancer. Your oncologist can help you make the best and most informed decision on what is needed to help you become cancer-free. Again, many of the possible cardiovascular side effects from breast cancer treatments are reversible and overall small in number. Treatment for breast cancer significantly reduces death. It will be important to treat and manage the risk factors that you already have (for example, diabetes, hypertension or hyperlipidemia) while you are receiving your breast cancer treatment and afterwards.

As always, it is never too late to embark on a healthier lifestyle including losing weight, if needed, getting more physical activity and stopping smoking.