Comparing Radiation Therapies for NSCLC
Intensity-modulated radiation therapy may be the preferred treatment option for patients with locally advanced non–small cell lung cancer (NSCLC), according to findings presented by Chun et al at the International Association for the Study of Lung Cancer (IASLC) 2023 World Conference on Lung Cancer (Abstract OA17.04).
For decades, three-dimensional conformal radiotherapy has been the standard of care for patients with locally advanced NSCLC who are unable to undergo surgery. However, the technique is less precise than intensity-modulated radiation therapy—which sculpts and molds radiation beams to tumor targets, reducing radiation exposure to organs such as the heart and lungs.
Study Methods and Results
In the long-term secondary analysis of the phase III NRG Oncology-RTOG 0617 study, researchers compared the outcomes of 482 patients with NSCLC who received 74 Gy of high-dose radiation or a standard 60-Gy dose of radiation from 2007 to 2011. All of the patients involved in the study underwent concurrent chemotherapy (carboplatin/paclitaxel with or without cetuximab) and either three-dimensional–conformal radiotherapy (53%) or intensity-modulated radiation therapy (47%).
After a follow-up of 5.2 years, the researchers found the patients who received the intensity-modulated radiation therapy had more than a twofold reduction in pneumonitis compared with those who received three-dimensional conformal radiotherapy (3.5% vs 8.2%).
“[Intensity-modulated radiation therapy] spared more normal tissue than [three-dimensional–conformal radiotherapy], which translated into a clinically meaningful benefit to patients,” highlighted lead study author Stephen Chun, MD, Associate Professor of Radiation Oncology at The University of Texas MD Anderson Cancer Center. “Despite historical concerns of [intensity-modulated radiation therapy] generating a low-dose radiation bath to a large area of normal lung tissue, we found no excess cancers, increased adverse events, or survival detriment over the long term related to this approach,” he added.
Although the patients treated with both techniques had similar survival rates, the researchers demonstrated a correlation between survival and radiation exposure to the heart. Intensity-modulated radiation therapy achieved significantly lower cardiac radiation doses.
Both the three-dimensional conformal radiotherapy and intensity-modulated radiation therapy groups experienced similar rates of new cancer development over time. Additionally, the researchers reported no evidence that age impacted survival, meaning that geriatric patients should not be excluded from curative-intent chemoradiation for locally advanced NSCLC.
“The data from our study make a compelling argument that we should use [intensity-modulated radiation therapy] for locally advanced lung cancer. As a randomized clinical trial comparing [the two techniques] is unlikely to be performed, this study represents the strongest prospective evidence we will ever have in support of [intensity-modulated radiation therapy],” Dr. Chun said.
Disclosure: The research in this study was funded by the National Cancer Institute, Bristol Myers Squibb, and Eli Lilly and Company.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.