Many of the patients in the older studies were treated with cobalt-60 radiation therapy and the side effects could include damage to heart and lung tissue. Today, most hospitals offer therapy with linear accelerators a more precise treatment.
The goal of Lally's research was to determine if the advances in radiation therapy technology would result in improved survival. Researchers analyzed results of 7,465 patients who had surgery for lung cancer. About half (47 percent) received radiation therapy after the surgery and 53 percent didn't.
In all patients, Lally and colleagues found that radiation treatment did not impact survival. However, when patients were compared based on lymph node involvement, there were clear differences. In patients where cancer had spread to high-risk regional lymph nodes, survival was improved with radiation therapy.
"For the patients who received surgery and radiation therapy, their survival was better than patients who received surgery alone," said Lally.
Lally said the study, which followed patients for 3.5 years, has limitations because the researchers didn't have information on some variables that might influenced the results, such as whether the patients had microscopic disease that may have been left behind after surgery. He said additional studies are needed to assess the role of radiation therapy and the emerging technology in treatment.
He also said that researchers need to continue to work to investigate the improving technology in hopes that all patients can gain benefit. Today, radiation oncologists are using CT-PET (computed tomography/positron emission tomography) and MRI (magnetic resonance imaging), to better visualize tumors and target them with radiation. Intensity modulated radiation therapy, another new technology, is able to control the radiation beam to deliver precise doses to specific areas within a tumor.