High-Dose Radiation Does Not Improve Survival in Stage III NSCLC
Miami, FL—A regimen of high-dose radiation had no survival advantage over standard radiation with concurrent chemotherapy in patients with advanced unresectable non–smallcell lung cancer (NSCLC) that had spread to the lymph nodes, according to an interim analysis of a late-breaking study presented at the 2011 American Society for Radiation Oncology meeting.
The phase 3 RTOG 0617 trial showed that overall survival was 74% in the high-dose group versus 81% in the standard-dose arm, and median survival was 22 months versus 20 months, respectively.
“The first study in 30 years to see if a higher dose of radiation would have a survival benefit found no benefit for 74 Gy over 60 Gy. The 74-dose arms were closed in June 2011, and we believe that the 60-Gy dose should remain the accepted standard,” said lead investigator Jeffrey D. Bradley, MD, Washington University, St. Louis, MO.
The study plans to enroll 500 patients with stage III NSCLC in this ongoing trial. This interim analysis was based on 423 patients randomized to 1 of 4 arms:
- Standard-dose radiation (60 Gy) plus chemotherapy (paclitaxel/ carboplatin) and cetuximab
- Standard-dose radiation with chemo – therapy and no cetuximab
- High-dose radiation (74 Gy) chemo – therapy plus cetuximab
- High-dose radiation with chemother apy and no cetuximab.
This study will also address the question whether cetuximab is of incremental benefit to radiation and chemotherapy in stage III NSCLC. This aspect of the trial is ongoing.
Both groups had similar baseline characteristics. The average follow-up time for the 423 patients has been 9 months. Until now, deaths have resulted primarily from the disease’s progression.
No significant difference in treatment- related toxicity was reported between the radiotherapy arms. Adverse events were similar in both groups. Grade 5 treatment-related adverse events occurred in 8 patients in the high-dose arm and in 5 patients in the standard-dose arm. Two deaths from radiation pneumonitis were reported for each arm.
A multivariate analysis showed that high-dose radiation, nonsquamous histology, and smaller tumor volume were significantly associated with a lower survival rate.
When asked why high-dose radiation did not improve survival, Dr Bradley indicated that the major challenge for patients with advanced lung cancer is distant metastases, and radiation is targeted at achieving local, not distant control. —PS