When should single fraction SBRT be offered for peripheral NSCLC?

Based on the updated results of RTOG 0915 single fraction radiation to 34 Gy in 1 fraction is reasonable to offer to any patient with a peripheral stage I NSCLC < 5cm (limited single institution data from Germany and Japan shows safety and efficacy even for large lesions).

While RTOG 0915 does include lesions abutting the chest wall, there is not clear data on how many such lesions were included/randomized, and it will be important to understand the rates of long-term toxicity to the chest wall ...

I would also add that I think 34/1 is a "reasonable" regimen, but not the standard of care. The RTOG 0915 was a phase 2 study powered to detect toxicity endpoints between 2 regimens in routine use, but not the RTOG standard of 54/3. The study was intended to set the stage for a phase 3 study of the winner and 54/3. As Greg Videtic has often said while presenting the data, it was a worthy question, but the NCI refused to fund it. So, I would caution docs to remember we don't honestly know if 34/1...

Facing this problem with a patient today, planning on 1 instead of 3 fraction regimen. Any rib dosimetry you can share? Presumably one should be "far" enough away i.e., well into the parenchyma, such that it is a nonfactor.