Intensity-Modulated Radiation Therapy Lessens Side Effects in Lung Cancer Patients
A new form of radiation therapy already used to treat prostate, brain, and head and neck cancers has now demonstrated efficacy for reducing the side effects of chemotherapy in patients with lung cancer.
In the study presented at the recent American Society for Radiation Oncology meeting in San Antonio, TX (October 18–21), lung cancer patients treated with intensity modulated radiation therapy (IMRT) had less severe toxicity than patients treated with conventional radiation therapy.
For years, the conventional method of radiation therapy for lung cancer patients has been the use of the three-dimensional conformal radiation therapy (3-D CRT), which shapes radiation beams to match the shape of the tumor. IMRT, a newer technique, uses advanced technology to manipulate those radiation beams and more precisely match the tumor shape, sparing more normal tissue.
In the study, 482 total patients with locally advanced non-small cell lung cancer were treated with radiation therapy; 53% were treated with 3D-CRT, and 47% were treated with IMRT. Patients in the IMRT were farther along in their symptoms than those in the 3-D CRT group, with more in stage IIIB of the disease (39% versus 30%), larger PTV (486 versus 427 mL), and higher PTC to lung ratio (.15 versus .13). After 2 years, researchers evaluated various survival-related endpoints, incidence of severe toxicity (grade 3 or higher), and amount of chemotherapy administered.
Although patients treated with IMRT had no statistically significant difference in 2-year overall survival, IMRT was far better tolerated than 3-D CRT. Patients treated with IMRT experienced significantly fewer cases of severe pneumonitis—lung inflammation that required oxygen, steroids, or mechanical ventilation, and/or led to death—than those in the 3-D CRT group, despite having larger tumors.
Lead author Stephen Chun, MD, University of Texas MD Anderson Cancer Center in Houston, and his coauthors suggest that IMRT could offer a significant opportunity to improve quality of life for patients with large tumors. "The data from our study makes a strong argument that we should routinely consider use of IMRT in locally advanced lung cancer," Dr. Chun concluded.