A study conducted by The University of Texas MD Anderson Cancer Center recommends intensity-modulated radiation therapy (IMRT) as the preferred treatment for locally advanced non-small cell lung cancer (NSCLC). IMRT significantly reduces lung and heart radiation exposure, leading to a more than two-fold reduction in severe lung inflammation compared to 3D-conformal radiotherapy (3D-CRT). These findings, presented at a lung cancer conference, suggest IMRT’s clinical advantage. Despite historical concerns, there was no evidence of excess cancer risk or survival issues. Age should not deter elderly NSCLC patients from curative-intent chemoradiation. Funding: National Cancer Institute, Bristol Myers Squibb, Eli Lilly and Company. Dr. Stephen Chun reported financial relationships with various entities.
On September 13, 2023, researchers from The University of Texas MD Anderson Cancer Center presented findings that emphasize the preference for intensity-modulated radiation therapy (IMRT) as the primary treatment option for patients diagnosed with locally advanced non-small cell lung cancer (NSCLC). This recommendation stems from the ability of IMRT to significantly reduce radiation exposure to critical organs such as the heart and lungs.
The results are based on an extensive secondary analysis of the NRG Oncology-RTOG 0617 Phase III study, which included a median follow-up period of 5.2 years. The analysis revealed that patients who underwent IMRT experienced more than a two-fold reduction in severe lung inflammation (pneumonitis) when compared to those treated with 3D-conformal radiotherapy (3D-CRT) – 3.5% versus 8.2%.
These compelling findings were presented at the International Association for the Study of Lung Cancer 2023 World Conference on Lung Cancer by Dr. Stephen Chun, an associate professor of Radiation Oncology. Dr. Chun emphasized, “IMRT proved to spare more normal tissue compared to 3D-CRT, ultimately delivering a clinically meaningful advantage to patients. Notably, concerns about IMRT potentially exposing a large area of normal lung tissue to low-dose radiation were unfounded, as we found no evidence of increased cancer risk, heightened adverse events, or detrimental effects on long-term survival associated with this approach.”
Traditionally, 3D-CRT has been the standard of care for locally advanced lung cancer when surgical intervention is not feasible. However, IMRT stands out due to its precision in sculpting and directing radiation beams precisely toward tumor targets, thus minimizing radiation exposure to vital organs.
The NRG Oncology-RTOG 0617 study, conducted from 2007 to 2011, enrolled 482 NSCLC patients, comparing high-dose radiation (74 Gy) to a standard dose (60 Gy). All participants underwent concurrent chemotherapy (carboplatin/paclitaxel, with or without cetuximab), with 53% receiving 3D-CRT and 47% receiving IMRT.
While both treatment groups exhibited similar survival rates, a closer examination of the data revealed a direct relationship between survival and radiation exposure to the heart. IMRT treatment plans consistently achieved significantly lower cardiac radiation doses.
Importantly, both the 3D-CRT and IMRT cohorts exhibited comparable rates of new cancer development over time. Moreover, the study did not uncover any evidence suggesting that patient age affected survival outcomes, reinforcing that age should not be a limiting factor for elderly individuals seeking curative-intent chemoradiation for locally advanced NSCLC.
Dr. Chun concluded, “The data from our study compellingly advocate for the use of IMRT in the treatment of locally advanced lung cancer. Given the unlikelihood of a randomized clinical trial directly comparing 3D-CRT and IMRT, this study represents the most robust prospective evidence supporting the use of IMRT.”
Funding for this trial was provided by the National Cancer Institute (R50CA275822, U10CA21661, U10CA180868, and U10CA180822), Bristol Myers Squibb, and Eli Lilly and Company. Dr. Chun disclosed financial relationships with various entities, including Curio Science, Norton Healthcare, AstraZeneca, Binaytara Foundation, Henry Ford Health, Hong Kong Precision Oncology, ViewRay, the American Board of Radiology, and the Japanese Society for Radiation Oncology. A complete list of collaborating authors can be found in the abstract linked here.