RTOG-0617: High-dose radiotherapy did not extend OS for advanced NSCLC
2011 ASTRO Annual Meeting
MIAMI - A dose of 74 Gy radiation therapy provided no survival benefit compared with 60 Gy for patients with advanced non-small-cell lung cancer, according to preliminary results from the phase-3 RTOG-0617 trial.
The study was designed to detect a median OS improvement of 7 months (24 months vs. 17 months) in the high-dose radiation arms. The trial was stopped early when researchers determined the high-dose arm had crossed the futility boundary after 90 deaths, the first of three planned safety analyses.
"I think it changes practice," Jeffery Bradley, MD, director of the S. Lee Kling Center for Proton Therapy at the Washington University Siteman Cancer Center in St. Louis, said of the results. "The standard dose should remain at 60 Gy. If physicians were using 60 Gy, before, they should go back to 60 Gy. It does not appear the higher dose is better."
Bradley presented the findings Monday at the 2011 ASTRO Annual Meeting.
From November 2007 to April 2011, researchers recruited 423 patients with unresectable stage IIIA/IIIB disease. Patients were assigned in a 1:1 ratio to either high-dose or standard-dose radiation. All patients in the study were assigned to concurrent chemotherapy with paclitaxel and carboplatin.
All patients underwent concurrent chemotherapy with carboplatin and paclitaxel.
Preliminary 1-yr OS rate was 74.8% (95%CI, 68.6%-80.0%) with significant follow-up remaining on the trial. Deaths are predominantly due to disease progression. There were seven grade-5 adverse events attributed to protocol treatment in the 74 Gy group vs. three in the 60 Gy group. Bradley said there was no significant difference in treatment-related toxicity between the two arms.
"It has been 30 years since the radiation dose of 60 Gy was established as standard. The techniques of radiotherapy have improved significantly over that time, so for this trial we adopted new techniques and new therapies. We asked whether a higher dose of radiation would improve overall survival. The answer came back very early, at the first interim analysis, that the higher dose is not better."
Bradley added that researchers evaluated both arms for several factors including patient and dosimetry factors. They found that there was no difference in outcome whether patients received 3D-conformal radiotherapy or IMRT.
RTOG-0617 is a four-arm study in which half of patients were assigned to treatment with cetuximab and half without. Researchers are still recruiting patients for the cetuximab arms and those results are not yet available. - by Jason Harris
For more information:
- Bradley J. LBA2. Presented at: 2011 ASTRO Annual Meeting; Oct. 2-6, 2011; Miami.
Disclosure: Dr. Bradley reported no relevant financial disclosures.
Intuitively, our specialty has always believed that more dose is better; the question is not how much to give, but how much can we give safely. The whole concept of modulation and guidance, and all of our technology revolves around the ability to give higher doses of radiation to more precisely targeted volumes, thus increasing the potential for cure while decreasing the risk for side effects. This study is so interesting because no we've learned 74 Gy is just as good as 60 Gy, at least in terms of number of deaths. This study should be a practice changer at least in the short term because there doesn't appear to be any advantage associated with the higher dose. We still don't have long-term results from the study and we still don't have the breakdowns of local control rate. Even though most patients die of metastatic disease, the question thus becomes, Is there a subset of patients within this dose range where they had a local failure that then caused them to have a cancer-related death? That data is not in this study yet because these are just interim results.
- Timothy Williams, MD
Medical director of Radiation Oncology with Lynn Cancer Institute at Boca Raton Regional Hospital
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