Precision hypofractionated radiation therapy (RT) may be a potent alternative for patients with non-small cell lung cancer (NSCLC) who cannot receive chemotherapy due to the potential for severe side effects.
Concurrent chemotherapy is the standard of care for patients with NSCLC, but it is often associated with severe hematologic and gastrointestinal toxicity. Because the risk of these treatment-related side effects outweighs the potential benefits that could be gained from treatment, concurrent chemotherapy is often not an option for patients with poor performance status. Such patients are often treated with hypofrationated RT instead.
In a study published in the International Journal Oncology, Biology, Physics, investigators examined whether advances in the technological application of hypofractionated RT have improved treatment. Fifty-five patients with advanced NSCLC who were not eligible for concurrent chemotherapy were enrolled in the trial. The median age of participants was 70 years. The primary endpoint was to determine the maximally tolerated dose (MTD) of RT, which was exceeded if one-third of evaluable patients experienced a severe treatment-related side effect during the study. Highly conformal RT was used in 15 fractions for a total dose of 50, 55, or 60 Gy. Patients had to experience a severe side effect or survive 90 days to be evaluable.
In all three dosage groups, 90-day follow-ups were complete without reaching MTD. In total, 93 grade 3 or higher adverse events occurred among participants, including 39 deaths, but it was believed that these were mostly due to factors other than RT. In addition, median overall survival was 6 months, with no significant difference among the different dosage levels.
Prospective analysis also revealed that hypofrationated RT is highly cost-effective, being significantly less expensive than conventional RT methods and only slightly more expensive than three-dimensional conformal RT.
The researchers, led by Robert Timmerman, MD (Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX), concluded that precise hypofractionated RT is generally well tolerated and does not result in increased toxicity levels compared to lower dose regimens. Because MTD was not reached, a phase 3 trial will determine whether even higher doses could be safely delivered.
