I have attached the full comment that I submitted to ASTRO below if anyone wanted to see my full reasoning. Feel free to use as a template if you want.
Thank you for the excellent guidelines for partial breast irradiation, it is very well written and researched. I have only one request/suggestion that I hope you will consider. For the techniques for partial breast radiation, it would be helpful if you included SBRT as an accepted technique.
The Livi regimen is 30 Gy in 5 fractions and was delivered with IMRT. While this technique was not called SBRT in the paper, their regimen would qualify as SBRT in the US under AAPM task group 101 definition of SBRT: “the delivery of large doses in a few fractions, which results in a high biological effective dose BED.” With appropriate imaging, machine QA and physician/physics supervision, it would also meet the characteristics of SBRT as set forth in table 1 of that paper (Benedect et al, Med Phys 2010). The link for the paper is provided below. 25-30 Gy in 5 fractions are also already considered stereotactic radiation in other disease sites such as CNS.
For financial reasons, a five fraction IMRT partial breast treatment will likely not be widely adopted, however, a five fraction SBRT partial breast treatment would. It is difficult to quantify the exact decrease in revenues from switching due to differences in fractionation and variability in reimbursement by payor. However, if we use the numbers provided by Meeks et al in table 3 in the paper linked below switching to 5 fractions IMRT treatment would decrease reimbursement per patient for a 15-fraction 3D conformal plan, 15 fraction IMRT plan and a 25-fraction 3D plan by ~1,500 dollars, ~5,400 dollars, and ~5,800 dollars, respectively. In contrast a five fraction SBRT plan would change reimbursement per patient for a 15-fraction 3D conformal plan, 15-fraction IMRT plan and a 25-fraction 3D plan by ~+3,800 dollars, ~0 dollars and ~-400 dollars. Depending on the fractionation and number of breast patients seen, switching eligible patient to a 5-fraction IMRT treatment could decrease reimbursement by hundreds of thousands of dollars per provider per year. However, a 5-fraction SBRT treatment would likely cause no significant change or a slight increase in reimbursement. Only a minority of centers can afford to lose hundreds of thousands of dollars per radiation oncologist, and thus a 5-fraction IMRT regimen will likely not be accepted. However, a 5-fraction SBRT regimen would likely be adopted.
A five fraction IMRT regimen would likely also worsen inequalities as minority patients are disproportionally treated at hospitals with limited financial resources where a 5-fraction IMRT regimen would be unlikely to be adopted.
I am aware that adding SBRT as an accepted technique would not solve all reimbursement issues for partial breast radiation, but it would be a good first step. Many great academicians/trialists have expended tremendous effort to make partial breast irradiation a reality. It would be a shame if it was not widely adopted due to a billing/technique issue.
https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1118/1.3438081
https://ascopubs.org/doi/pdf/10.1200/OP.21.00298?role=tab