A woman’s risk of long-term cardiac side effects from radiation therapy when treating left-sided breast cancer could be reduced through the use of a new form of surface imaging, available at the Cancer Therapy & Research Center (CTRC).
By taking a deep breath and holding it, the space between the breast and the heart widens, minimizing or eliminating radiation exposure the heart may receive during radiation therapy. The technique, called Deep Inspiration Breath Hold, isn’t unique, but the CTRC is one of only a handful of centers nationwide that pair it with surface imaging that allows the treatment team to see exactly when the maximum separation occurs.
“Conventional techniques of radiation therapy for left breast cancer give a dose of radiation close to the surface of the heart,” said CTRC radiation oncologist Richard L. Crownover, M.D., Ph.D., professor in the Long School of Medicine. “This is significant because coronary arteries are on the surface of the heart. The exposure may lead to other effects, basically the acceleration of atherosclerosis or ‘hardening of the arteries.’ This becomes a risk factor for heart attacks years later, especially for younger women.”
Deep Inspiration Breath Hold enables the treatment team to accurately position the patient each time a treatment is done. They can position the patient into the same exact spot, to within a few millimeters, each day during a course of treatment.
The radiation is “gated”—the system does not allow the radiation beam except when the patient is in the correct deep breath hold position, Dr. Crownover said.
Special goggles tell the patient when to breathe. The patient sees a bar and a box in her field of vision, and when she breathes the bar goes up and down. The care team practices this with the patient at a simulation session prior to the start of treatment.
“This reduces radiation exposure to the coronary arteries, which is expected to reduce the risk of problems down the road,” said radiation oncology physicist Alonso N. Gutiérrez, Ph.D., associate professor in the Long School of Medicine.