Researchers have determined that the standard radiation dose of 60 Gy should remain in place for persons with stage III non-small cell lung cancer (NSCLC), now that an interim analysis of a phase III trial has shown that a higher dose of 74 Gy does not improve survival.
To compare the overall survival of stage III NSCLC patients treated with high-dose vs standard-dose radiotherapy with concurrent chemotherapy, radiation oncologist Jeffrey Bradley, MD, of the Washington University School of Medicine in St. Louis, Missouri, and co-investigators randomized 423 participants to four treatment arms:
- high-dose radiation therapy with the chemotherapy agent cetuximab
- high-dose radiation therapy without cetuximab
- standard-dose radiation therapy with cetuximab
- standard-dose radiation therapy without cetuximab.
All patients received concurrent chemotherapy with paclitaxel and carboplatin.
As the researchers reported at the annual meeting of the American Society for Radiation Oncology, held October 2–6, 2011, in Miami Beach, Florida, early findings (median follow-up 9.1 months) revealed that persons receiving the higher dose of radiation did not have better survival rates than did those receiving the standard dose. Therefore, the two high-dose-radiation arms of the trial were closed, and the study continues with the comparison of the 60 Gy radiation dose with and without cetuximab. Toxicity did not explain the early inferior survival with 74 Gy; no significant difference in treatment-related toxicity was observed between the two radiation therapy arms, but additional data on outcome and toxicity is pending.
“The trial provides class I evidence that the standard dose of radiation therapy for stage III lung cancer should remain at its existing level of 60 Gy and doses as high as 74 Gy are not better in curing stage III lung cancer,” noted Bradley in a statement announcing the early results. “We are not sure why this is the case, and our data is still being carefully reviewed.”