For non–small cell lung cancer that has metastasized to the lymph nodes, a higher dose of radiation (74 Gy) does not increase overall survival compared to the standard radiation dose (60 Gy), according to an interim analysis of a randomized study presented at the 53rd Annual Meeting of the American Society for Radiation Oncology (ASTRO).
“Most radiation oncologists and lung cancer specialists are surprised by this finding. Although the optimal radiation dose for lung cancer patients has not been tested in a randomized phase 3 trial for over 30 years, most believed that higher doses of radiation cured more patients with lung cancer,” said Jeffrey Bradley, MD, a radiation oncologist at the Washington University School of Medicine in St. Louis.
The goal of the phase 3 trial was to determine if higher doses of radiation improve survival, and also if the chemotherapy drug cetuximab increases survival among patients with stage 3 non–small cell lung cancer. Researchers randomized 423 patients to 1 of 4 treatment arms: standard-dose (60 Gy) versus high-dose (74 Gy) radiation therapy and chemotherapy with or without cetuximab. During the trial, 2 types of external beam radiation therapy were used: three-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy.
Early findings show survival rates for patients who received the higher dose of radiation (74 Gy) did not improve over those for patients receiving the standard dose (60 Gy).
“The trial provides class 1 evidence that the standard dose of radiation therapy for stage 3 lung cancer should remain at its existing level (of 60 Gy) and doses as high as 74 Gy are not better in curing stage 3 lung cancer,” Dr Bradley said. “We are not sure why this is the case and, our data is still being carefully reviewed.”
Source: ASTRO.