"Post-operative radiation therapy has failed to demonstrate a survival benefit in the past, likely because previous studies used older equipment," said Brian Lally, M.D., a radiation oncologist at Wake Forest University Baptist Medical Center and lead author. "Our study, which examines the results using modern equipment, shows survival benefit in select patients."
The study analyzed data from the Surveillance, Epidemiology and End Results Database (SEER), a national program that collects information on cancer cases from registries that represent 26 percent of the U.S. population. Lally began the research at Yale University School of Medicine before he joined Wake Forest Baptist.
The analysis found that in patients whose disease had spread to the regional lymph nodes between the lungs, overall survival at five years was 27 percent in patients receiving surgery plus radiation therapy, compared to 20 percent in patients who were treated with surgery alone.
"Lung cancer is the leading cancer killer in this country and even with the best therapy, survival is poor; so an increase of this level can be considered significant," said Lally. "I speculate that the improvement in the technology available to deliver radiation therapy is responsible for this increase."
In the past, the combination of surgery/radiation therapy was the standard of care for lung cancer. However, this practice shifted dramatically after an analysis of nine studies found that radiation therapy had a detrimental effect on survival. Today, most lung cancer patients are treated with surgery and chemotherapy and less than one-third receive radiation therapy.
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.
"We are becoming very precise with delivering the radiation to the tumor and reducing the risk of damage to surrounding tissue," he said.
Co-researchers are Daniel Zelterman, Ph.D., Joseph Colasanto, M.D., Frank Detterbeck, M.D., and Lynn Wilson, M.D., all from Yale, and Bruce Haffty, M.D. from UMDNJ-CINJ at New Brunswick.
Wake Forest University Baptist Medical Center is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university's School of Medicine. The system comprises 1,187 acute care, psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of "America's Best Hospitals" by U.S. News & World Report.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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