Fuerst, Mark L.
If you're a survivor of childhood and adolescent cancers, you remain at high risk for cardiovascular disease several decades after you've completed your cancer therapy.
A questionnaire conducted by the Childhood Cancer Survivor Study looked at nearly 15,000 adults who had survived a variety of childhood and adolescent cancers. Compared to their healthy siblings, the cancer survivors who had been exposed to radiation to the heart showed a two- to six-times increased risk of heart failure, heart attack, disease of the heart lining (pericardial disease) and heart valve problems. Survivors who had chemotherapy regimens that used drugs called anthracyclines had a two- to five-times increased risk of the same heart problems. Their heart issues continued to increase up to 30 years after their cancer diagnosis.
“The latency period [the time from treatment to the onset of heart problems] for radiation-induced effects from cancer treatment is about 20 years,” says Smita Bhatia, M.D., M.P.H., chair of the Department of Population Sciences at City of Hope National Medical Center in Duarte, Calif. “The increased risk is clearly related to radiation to the chest for Hodgkin's lymphoma patients.”
Radiation has been the standard therapy for stage 3 or 4 lymphoma for decades, Bhatia says. In the 1970s, when anthracycline-based chemotherapy was introduced, it was added to radiation treatments for high-risk lymphoma patients. Low-risk lymphoma patients did not receive chemotherapy because at the time it was believed there were no long-term side effects from radiation therapy. “Now we realize that there are long-term complications from radiation, as well as late effects from the use of anthracyclines,” she says. “Therefore, we minimize radiation therapy and use lower doses of anthracyclines to decrease the heart risks.”
TOOLS TO ASSESS YOUR RISK
If you have had treatment for cancer, you can become more aware of your heart risks with a tool developed by the National Children's Cancer Society (NCCS). The Society has a free, secure, online assessment tool available at lea.beyondthecure.org that allows you and your doctor to enter data about your cancer history, including gender, year of and age at diagnosis, treatments received, radiation sites and surgery. Based on the data entered, the program lists potential late effects that you may experience, provides recommendations for follow-up care, offers prevention tips and suggests links to follow-up clinics throughout the United States, as well as other sources of information.
The easy-to-navigate NCCS tool provides a good starting point to open up a conversation with your doctor. If you have not been followed closely beyond cancer treatment, you can gather key information to take to your primary care doctor or cardiologist.
The Children's Oncology Group (COG) periodically updates its extensive guidelines for follow-up of childhood cancer survivors, available at childrensoncologygroup.org/index.php/survivorshipguidelines. In the section on radiation, for example, the guidelines recommend periodic echocardiograms based on your age at radiation therapy and the dose you received. The guidelines also report potential late effects, risk factors and at-risk populations, and recommend specific follow-up goals.
“Screening may pick up effects to the heart earlier, but the COG guidelines don't recommend screening every cancer patient for coronary artery disease,” says Bhatia. The guidelines do, however, recommend aggressive control of cardiovascular risk factors. “If you received radiation therapy for cancer up to 20 years ago, you need to make sure to minimize your cardiovascular risk factors,” she says. “Eat heart-healthy foods, exercise regularly, don't smoke and control your blood sugar, cholesterol and blood pressure levels.”