Radiation therapy is a common treatment for cancer, but it can also cause damage to healthy cells in the treatment area. Researchers have identified 78 patient deaths (0.55%) associated with radiation treatment, which can occur during or after the treatment period. Different cells and tissues in the body support radiation differently, with rapidly dividing cells being the most affected. This includes skin cells, cells that line the mouth and gastrointestinal (GI) tract, and bone marrow blood cells. Radiation therapy can also cause problems with the heart and vascular system (circulation).
Cardiotoxicity can develop days or months after radiation, but often develops years later. This can reduce the patient's quality of life and increase the risk of death from heart-related causes. Heart disease is a very important and not uncommon long-term side effect of radiation therapy. Skin problems are common with external radiation therapy because radiation travels through the skin to the area where the treatment is being directed. Radiation therapy to treat lymphoma and cancers of the lung, esophagus, spinal cord, and breast often targets structures in the chest.
These side effects, such as high blood pressure, abnormal heart rhythms, and heart failure, can be caused or exacerbated by chemotherapy and radiation therapy, as well as newer forms of cancer treatment, such as targeted therapies and immunotherapies. In recognition of the risk of cardiotoxicity from radiation, newer radiation techniques have been developed that minimize radiation to the heart. A cardiologist and an oncologist working together can determine a patient's individual risk of cardiotoxicity by performing certain tests and images before starting radiation therapy. Radiation therapy to the brain, base of the skull, and neck can cause cognitive problems such as memory loss and difficulty concentrating. Radiation can also cause lymphedema, swelling that occurs as a result of damage to the lymphatic channels. To reduce cognitive problems later on, radiation oncologists now frequently treat people with a medication during radiation therapy. It is estimated that 50% of people diagnosed with cancer will receive radiation therapy at some point during their trip.
For example, in patients with Hodgkin's disease receiving radiation therapy (which is not so common now), the leading cause of death is cardiovascular disease, not cancer. A special group of at-risk patients are younger, otherwise healthy patients treated for early-stage breast cancer and Hodgkin lymphoma who are cured of cancer and live for many years after treatment. The goal is to understand a patient's risk of suffering from cardiovascular disease when cancer is diagnosed and then to control that risk throughout cancer treatment and after. When a patient develops cardiac side effects during treatment, the physician may modify the dose of a therapy or discontinue therapy altogether.