Can treatment for cancer affect the heart?
Two important ways in which cancer treatment can affect the heart are due to medications given for cancer and radiation given to organs near the heart giving unwanted radiation to the heart.
Effect of cancer medications on the heart
Most common cause of defective heart function due to cancer treatment is chemotherapy using a group of medications called anthracyclines. Adriamycin is one of the medications in this group, though there are other related drugs as well. Other types of chemotherapy medications can also cause damage to the heart muscles. Some type of chemotherapy medications can also damage the blood vessels supplying the heart. Hence evaluation of heart function is routinely undertaken before cancer chemotherapy with these medications. Effect on heart function can occur early in the course of treatment or delayed, even decades later, though rare. Most often it is somewhat related to the dose of medications, the probability increasing with increasing cumulative dose.
Effect of radiation on the heart
Effect of radiation on the heart can be on the heart muscle causing a form of heart muscle disease known as restrictive cardiomyopathy or on the covering of the heart (pericardium) causing a condition known as constrictive pericarditis. In addition to this radiation can cause damage to the blood vessels supplying the heart and sometimes the valves within the heart. Left sided heart valves are more often involved than those on the right side of the heart.
When both radiation and chemotherapy are given to the same person, the chance for damage to the heart is more. But this does not mean that treatment should be denied for a potentially life threatening disease like cancer. Adequate precautions can be taken to minimize the damage and monitoring for early detection can help in early treatment. Modern radiation equipment can minimize collateral damage to the heart by special techniques by focusing the radiation beam to the cancer cells thus avoiding injury to heart.