The Cancer-Cardiac Connection
October 1, 2018
When cancer strikes, there is potential for heart damage. Specialists in cardio-oncology can help minimize this damage. “We want to protect the heart as much as possible during and after cancer treatment,” says Vlad Gabriel Zaha, M.D., Ph.D., a cardio-oncologist at UT Southwestern’s Simmons Comprehensive Cancer Center, and one of the few such specialists in the Dallas area.
Cancer can harm the heart in three ways: Some common types of cancer treatments, such as radiation, chemotherapy, and immunotherapy, can lead to heart problems. Biochemicals produced by some cancer cells can trigger heart damage. Cancer can develop directly in the heart.
Dr. Zaha points out that many people are living with cancer that’s in remission or with very slow progression. So, it’s important to pay attention to other health risk factors. Evaluating heart health soon after a cancer diagnosis can help doctors build the safest treatment plan and watch for problems during and after treatment.
Cardio-oncologists help people understand how they can help keep their hearts healthy and what symptoms might need immediate attention. Dr. Zaha notes that some heart-related side effects of cancer treatment can be serious if not caught early, while others will likely pass with time. Also, some side effects occur during the treatment period, while others might develop years after the cancer has been treated.
In addition, large studies have found that certain cancers are associated with more cardiovascular risk, and that, conversely, cardiovascular disease is associated with some cancers. “The risk of cardiovascular disease and the risk of cancer are intersecting in a complex way,” Dr. Zaha says.
Spotting Heart Problems Early
A UT Southwestern clinical trial funded by the Cancer Prevention and Research Institute of Texas (CPRIT) aims to spot early changes in heart function in certain patients with cancer.
The study is focusing on the chemotherapy drug doxorubicin (Adriamycin), an important weapon in the fight against breast cancer, around for more than 50 years, and still used to treat many patients when more targeted alternatives are not available. While the drug is effective, in an estimated 5 to 10 percent of people, it can lead to heart problems.
Doctors don’t know which people will develop these problems until symptoms start to occur. “The disease is not very easy to identify early on,” Dr. Zaha says. “If we could identify it early, that would open the possibility for preventing the progression of heart disease.” Patients requiring such a treatment are encouraged to discuss their diagnostic study eligibility with the clinical team or contact the CTox study research team directly at 214-645-6269.
Researchers aim to enroll up to 100 pre- and postmenopausal women in the study over the next four years, monitoring them for early signs that their chemotherapy treatments might be harming their hearts.
They’ll be watching for biochemical changes that occur in the heart. These changes indicate damage, but the cardiovascular system compensates for them at first. Without any symptoms driving people to seek care, the heart damage can progress unnoticed. For the study, a substance is administered via IV. Then, researchers examine how MRI is able to detect these biochemical changes before symptoms set in. “It’s fundamentally a more advanced way to investigate the function of cells in the body,” Dr. Zaha says.
By knowing each patient’s potential for heart damage, doctors may be able to develop a personalized approach that could maximize both a patient’s cancer treatment and their heart health. For example, some people might show clear markers for heart problems with relatively low levels of chemotherapy. So, other types of chemotherapy might be better choices for them. Other patients might not show any signs of heart issues, so they could be treated with increased levels of chemotherapy if that was what was needed to improve their cancer outcomes.
In addition to breast cancer, this type of chemotherapy drug is used to fight other cancers, including some lymphomas and sarcomas. So, identifying early changes in the heart could ultimately also help improve treatment for people with those diseases.
Identifying the Need
Breast cancer patients most in need of cardio-oncology care include those who:
● Are receiving radiotherapy (if the radiation field includes the heart) or chemotherapy (especially cardiotoxic drugs, such as the following classes: anthracyclines and HER-2 blocking agents) or immunotherapy (checkpoint inhibitors, evaluated in new clinical trials).
● Those with underlying cardiovascular disease, including congestive heart failure, arrhythmias, ischemic heart disease, history of heart attack or stroke, uncontrolled hypertension, and congenital heart disease.
● Patients at risk for cardio-metabolic disease: BMI outside of the normal range (<20 or >25), sedentary, frail, with a significant personal or family history of cardiovascular or metabolic disease like high cholesterol and diabetes.
● Patients with prior treatment with cardiotoxic therapy including left chest radiation and anthracyclines, due to the possible late cardiotoxic progressive effects.
● Are age 65 or older.