Aiming to protect the heart from radiation therapy
Can treatment for cancer cause more health problems than the disease itself? It’s a question people fighting cancer often ask as they consider how treatment side effects will make them feel, and whether treatment such as chemotherapy and radiation can pose long-term risks to their health.
Last March, The New England Journal of Medicine published an article raising concern about radiation’s toxicity to the heart in patients who receive radiation treatment for breast cancer. It stated that even low doses of radiation to the heart put patients at risk for developing heart disease.
But Dr. Lanceford Chong and his colleagues in the Radiation Oncology Department of our hospital near Phoenix, cautions that the study is outdated and doesn’t reflect the level of precision and sophistication used in treating breast cancer with radiation today.
Dr. Chong says, “With complex treatment planning and contemporary IMRT technology using tiny, pencil-thin beams of radiation, we can better treat breast and lung cancer and help minimize radiation to the heart.”
The study profiled in the article followed approximately 2,000 patients in Sweden and Denmark between 1958 and 2001, a period in which radiation therapy machines and delivery techniques were less targeted than today. Current intensity modulated radiation therapy (IMRT) technology was not available until early 2000.
Simon Lam, the hospital’s Chief Medical Physicist and Radiation Safety Officer, adds that patients today are receiving far less radiation to the heart–perhaps less than one-third the cardiac dose patients analyzed in the study received. Lam cites a recent response by David J. Brenner, PhD, DSc of Columbia University Medical Center and his colleagues to the study. Dr. Brenner’s team estimated “the lifetime excess risk for major coronary events” (e.g., heart attacks) for breast cancer patients treated with radiation today ranged from 0.05 to 3.52 percent.
The good news is patients needing radiation treatment may have less to fear as state-of-the-art radiation therapy delivery equipment and treatment planning technology help target the radiation where it’s needed and reduce risk to the heart.
Advances in radiation therapy benefit patients
Because of the heart’s location, treating the left breast or lung with radiation can pose more of a challenge than treating the right breast or lung. But Dr. Chong says the use of IMRT and sophisticated treatment planning help the team develop a customized and targeted plan to treat these areas, particularly if the regional lymph nodes also need to be treated.
Dr. Chong adds, “Treatment planning often allows us to minimize the volume of the heart irradiated as well as the radiation dose to the heart.”
Dr. Chong also uses precise positioning of patients when radiation is administered with image guided radiation therapy (IGRT). Patients are set in the same position each day, helping ensure radiation is pinpointed to the cancer rather than the healthy surrounding tissue. Using a CT scan, IGRT can detect changes in a tumor’s position as small as 1 millimeter.
Lam says in addition to today’s high precision radiation equipment, patients benefit from the personal attention they receive from the medical physics staff, which works closely with radiation oncologists to tailor radiation treatment to the individual needs of patients. When planning treatment, the team analyzes the volume of the heart and the breast or lung needing treatment to determine the appropriate dose of radiation each patient needs.
“Paying attention to all of these details creates a culture of medical excellence we feel is not only important, but mandatory for the care of our patients,” says Dr. Chong.