BOSTON - Patients with stage I non-small cell lung cancer (NSCLC) who were treated with stereotactic body radiation therapy (SBRT) had more than twice the survival of patients treated with conventional radiation therapy, according to a study presented on Sunday at the American Society for Radiation Oncology (ASTRO) meeting.
Researchers followed patients in the U.S. Veterans Health Administration (VHA) from 2001 to 2010 to track those who received SBRT, a form of radiation therapy that uses imaging guidance to direct highly targeted radiation to a tumor and limit damage to surrounding tissue.
Dr. Matthew Boyer, PhD, from Duke University.Dr. Matthew Boyer, PhD, and colleagues identified 486 patients who received SBRT for stage I non-small cell lung cancer during the study period, and they compared them with 1,203 patients who received conventional radiation therapy. Primary outcomes were overall survival and lung cancer-specific survival four years after radiation therapy.
At the four-year follow-up point, overall survival had more than doubled for the SBRT group, with 28.5% of patients still alive, compared with 12.7% of patients in the conventional radiation therapy group, according to the researchers.
With respect to lung cancer-specific survival, the SBRT group had a rate of 50.4% at the four-year mark, compared with 33.9% in the conventional group. The researchers noted that the increase in survival occurred with rising use of SBRT in the Veterans Affairs system, from 4.7% to 60.3%.
When analyzing the data for multiple variables, they found that using SBRT was associated with a nearly 30% reduction in risk of death, with a hazard ratio of 0.72 (p < 0.001).
In other findings, using PET to stage patients did not result in a demonstrable improvement in survival: The hazard ratio was 0.88, but the findings were not statistically significant (p = 0.084). In addition, the era in which patients were treated (2006-2010 versus 2001-2005) did not make a statistically significant difference.
The PET and treatment-era findings demonstrated that the improvement in survival was due to increased use of SBRT and not better staging due to PET or other improvements in treatment over the study period, the researchers concluded.
The findings can be generalized outside the VHA system, and they indicate that SBRT should be the standard treatment for patients with stage I NSCLC who undergo radiation, according to Boyer, a resident in radiation oncology at Duke University.
"It is very rare for a study to show that double the number of patients were likely to be alive at four years due to the introduction of a new treatment," he said.
