Breast cancer survivors may die of heart disease

(Reuters Health) - The same advances in breast cancer treatment that have dramatically improved survival in recent years have also left a growing number of women vulnerable to potentially fatal cardiovascular problems, the American Heart Association warns.  

Chemotherapy can weaken the heart muscle, some newer targeted medicines can increase the risk of heart failure, and radiation can cause heart rhythm disorders and structural damage in the arteries and heart valves, the AHA emphasizes in its scientific statement on the link between breast cancer and heart disease.  

Cardiovascular disease is the number one cause of death in women, and this risk increases with age, noted Dr. Laxmi Mehta, lead author of the statement and section director of preventive cardiology and women’s cardiovascular health at the Ohio State University Medical center in Columbus.  

“So as breast cancer survivors are living longer, their risks of cardiovascular disease increase,” Mehta said by email.  

Breast cancer survivors, especially women over age 65, are more likely to die from cardiovascular disease than tumors, the AHA statement stresses.  

This doesn’t mean women should skip lifesaving cancer therapies, but it does mean they should be aware of the cardiac side effects and be monitored for cardiovascular disease during treatment and afterwards, Mehta added.  

“Any patient who is going to undergo breast cancer treatment, whether they have heart disease at the beginning or not, should be aware of the potential effects on their heart,” Mehta advised.  

Several cancer treatments have long been linked to an increased risk of heart problems in the future.  
For example, anthracyclines, such as doxorubicin, are a type of chemotherapy that has been used since the 1970s and can cause irreversible damage to the left ventricle, the heart’s main pumping chamber.  

And taxanes, such as paclitaxel, have been linked to irregular heart rates and rhythm disorders.  
Trastuzumab and pertuzumab, targeted therapies for an aggressive type of malignancy known as HER-2 positive breast cancer, can also damage the left ventricle but this damage may be reversible after treatment stops. Women who develop heart failure while taking these drugs may be able to alter treatment to help prevent worsening or permanent cardiac damage.  

Another chemotherapy - doxorubicin - can damage heart cells, but the risk of heart failure may be reduced when the medicine is administered slowly, rather than all at once. Women taking this medicine may also reduce their risk of heart failure by pairing it with another drug, dexrazoxane.
  

Radiation can damage arteries and cause blockages, but newer techniques can deliver lower and more targeted doses of radiation that are less toxic to the heart than standard regimens a generation ago.  
Heart disease and breast cancer share many of the same risk factors, including obesity, inactivity, smoking, and poor eating habits, according to the AHA statement published in Circulation. Lifestyle changes designed to avoid these risk factors may help women minimize their risk of cancer and heart problems.  
“Women have a higher risk for heart disease if they go untreated for existing cardiovascular risk factors or develop risk factors such as obesity or low fitness during breast cancer treatment,” said Dr. Susan Gilchrist, a cardiology professor at the University of Texas MD Anderson Cancer Center in Houston.  
Even when women don’t have any risk factors for heart disease when they’re diagnosed with breast cancer, they should still adopt a heart-healthy lifestyle to lower the chances of developing heart problems associated with cancer treatments, the AHA recommends.  
“The key message is to be proactive and focus on prevention,” Gilchrist, who wasn’t involved in the AHA statement, said by email. “Stay active during treatment, avoid smoking and weight gain, get to goal with blood pressure and cholesterol, and do appropriate cardiovascular screening as determined by your oncologist.”