Dr. Jeffrey Bradley, Radiation Oncologist at Washington University in St. Louis, provides trial evidence showing that patients may not benefit from high dose chest radiation therapy vs. standard dose therapy.
This is a topic I’ve been a little passionate about over the past ten years or so. We published a paper in Lancet Oncology this past February, it was RTOG 0617, and it was a comparison of high dose radiation therapy, 74 Gy, versus standard dose radiation, 60 Gy, in patients with stage III non-small cell lung cancer. They were unresectable, they received either the high dose or standard dose of radiation, and they were further randomized to receive cetuximab or not; cetuximab is an EGFR antibody.
The trial was published — it didn’t show an advantage to high dose radiation therapy, in fact, it shows a disadvantage to high dose radiation therapy. The median survival of the patients that were treated with 60 Gy without cetuximab was 28 months, compared to 20 months for patients receiving high dose radiation therapy. It turns out, even though we used the most sophisticated treatment techniques at the time, perhaps normal tissue doses were the cause of the high dose arm failing to achieve a better outcome, and a poor outcome in fact. We look at this as the heart dose — it turned out to be very important. We didn’t place heart dose constraints because, at the time, no one was placing heart dose constraints, and now we find out that’s very important. So, our subsequent trials have included heart dose constraints going forward, within, at least, the Energy Oncology Cooperative Group.
Likewise, there was no advantage to cetuximab in this patient population. These patients were unselected for EGFR status, and there’s an indication from the paper that if you look for EGFR status, people who had a high H-score may have benefitted from that drug. Nevertheless, there was no distinct survival advantage to receive cetuximab.
So the standard of care nowadays is 60 Gy with concurrent chemotherapy — in that trial we used weekly paclitaxel and carboplatinum. We also used two cycles of consolidative chemotherapy in that study.