Whole breast radiotherapy has been linked to damage in the heart and lungs, along with an increased risk of cardiovascular mortality. Researchers from the Cancer Institute at NYU Langone Medical Center theorize damage to the heart and lungs can be reduced by lying on your stomach rather than on your back.

Silvia C. Formenti, MD, Professor of Oncology and chair, Department of Radiation Oncology, conducted experiments from November 2005 to December 2008 on patients with stage IIA, which describes invasive cancer that has either no tumor but cancer cells in the lymph nodes under the arms, a tumor that measures two centimeters or smaller that has spread to the lymph nodes, or a tumor larger than two centimeters but smaller than five centimeters that has spread to the lymph nodes.

Four hundred patients were enrolled in order to uncover the difference in lung and heart volume exposure to radiation between the supine (lying on their back) and prone positions (lying on their stomach) for patients with left breast cancer and in lung volume for patients with right breast cancer. Patients underwent two tomography simulation scans first under supine position and then prone position.

Dr. Formenti found that in all patients who were treated in the prone position, there was a reduction in lung volume exposed to radiation for right breast cancer compared to the supine position. In 85 percent of patients with left breast cancer the prone position was linked to reduced heart volume exposure compared to the supine position. That meant for 15 percent of patients with left breast cancer the supine position provided less heart volume exposure to radiation.

"Prone positioning was optimal in sparing the lungs in virtually all right breast cancer cases, and for 85 percent of left breast cancer cases," Dr. Formenti said to Medical Daily.

She also points out that the trial demonstrated the prone setup reduces the amount of respiratory motion of the chest wall, which may further improve the accuracy of targeting during breast cancer treatment. In contrast, the prone setup appears to be inadequate for breast cancer patients requiring radiotherapy to the lymph nodes located under an individual's arm.

Dr. Formenti told Medical Daily, "This is an important study as it shows that by treating women in the prone position vs. supine position, we can reduce radiation to the lungs and heart significantly. Knowing this may change the way we treat in the future."

The study was published in the Journal of the American Medical Association.