SBRT to stimulate abscopal effect?

[deleted18755]

Colleagues,

At least a few regular posters on this forum have mentioned how they receive referrals from medical oncologists for patient's with presumably widely (or at least not oligo) metastatic disease for SBRT to again a single or a few (but not all) sites to stimulate the abscopal effect. This has been mentioned as a potential area for increased utilization of radiation therapy and I would certainly agree but the data are not strong (or at least underdeveloped).

I spoke with a friend or two and they agreed with me but also told me that the latest version, out as recently as a few weeks ago, of one of the major payer's guideline (I think Evicore but I can check) modified their SBRT section to specifically make note that SBRT to stimulate abscopal effect is NOT medically necessary and will not be compensated.

For those of you who regularly do this can you please elaborate on how you developed the program/referral base (informal or formal interactions/talks with medical oncologists or did they ask you about it, what data do you use to support it, have you collected your own data, etc?) and do you bill it as standard SBRT and/or are you aware that at least some payers are now specifically calling it not medically necessary?

There is so much potential here . . . I really wish our "academic" colleagues would take off with this, which could really elevate our field a bit, rather than endless garbage retrospective reviews/SEER analyses that literally nobody but the the authors and journal reviewers bother reading or just another hypofractionation trial.

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[seper]

When talking to Evicore, try to push it through as curative-intent therapy for oligometastases. I've had some limited success.

 

[evilbooyaa]

So, to clarify, it's not every single patient that we do this on (at least at my institution); it's those with 1) upfront oligometastatic disease (usually oligometastatic recurrence of disease, as then the primary is well controlled), or, in patients with evidence of widely metastatic disease, it's in the 2) oligoprogressive setting, meaning that the systemic therapy they are on is controlling all but 1 or 2 (maybe up to 3) lesions well and those specific lesions need spot treatment so that the patient can continue with the systemic therapy that is working for 90%+ of their disease. In rare situations, we radiate when a patient is 3) re-initiating immunotherapy after not having been on it for some time (when med onc is re-challenging them with the immunotherapy).

SBRT for the first two scenarios is likely preferred due to the ablative potential. 3rd scenario, IMO, doesn't necessitate SBRT.

Even the original melanoma NEJM report was when immunotherapy stopped working in that patient, they got radiation, then it started working again.

I'm insulated from a fair number of insurance issues at my institution - a lot of the patients we do this on are Medicare, for which my institution has free reign to basically do whatever we want within reason. I've very rarely gotten some push back from private insurers in patients younger than 65. If it gets denied by insurance, there isn't a slam-dunk paper that can be shown to insurance.

In regards to generation of the abscopal effect, there is radiobiological hand-waving about greater antigen presentation with SBRT over conventional fractionation, but if you look at the rare published data in this space, I can't find anything that says that SBRT is better than standard fractionation at producing the abscopal effect at a clinical level. So you have that as a back-up, that it's not SBRT or bust in this scenario for abscopal effect stimulation.

I do agree that an immunotherapy +/- RT (either SBRT or conventional fx or randomized to either) is long over-due to see results for.

 

[OTN]

SBRT for oligometastatic dz progression is what I use. I agree with Evicore, actually (shudder), in that there really isn't any good data for XRT use for abscopal stimulation yet, due to the academics failing us. Hopefully soon.

 

[BobbyHeenan]

When talking to Evicore, try to push it through as curative-intent therapy for oligometastases. I've had some limited success.

Especially in the case of lung it is specifically within NCCN guidelines now in the "principles of radiation" section to consider ablative therapy to oligomets.

I'd try to hang your hat on this more so than any abscopal effect if it's a lung patient.

 

[seper]

With lung cancer, Evicore now seems to like solitary site SBRT, but 2 separate lesions are not allowed.

 

[Radiator20]

the data are not strong (or at least underdeveloped).

I agree entirely. For the amount of excitement there seems to be around this concept, I'm shocked by just how little real data there is.

there is radiobiological hand-waving about greater antigen presentation with SBRT over conventional fractionation

Having said the above, and in addition to whatever effect fraction size may have on antigen presentation, one further reason why very SBRT-like/hypofractionated regimens might be be more effective at potentiating an abscopal effect: generating an abscopal effect probably requires immune cell activity within the target lesion. But T cells, etc are obviously radiosensitive. So 30 fx just means 6 weeks of killing off all the immune cells that are trying to respond to the tumor. (All the more if you're treating regional LNs, which presumably also play some role in the anti-tumor immune response) Whereas with SBRT-like regimens, you get in whatever secret sauce RT adds, but do in ~5 fx, so only kill off the earliest T cells, and leave plenty of room thereafter for an immune infiltrate to arrive and an anti-tumor immune response to develop. Of course, that's pure theory--but it does make intuitive sense.

 

[radiaterMike]

evilbooya- when you say “ a lot of the patients we do this on are Medicare, for which my institution has free reign to basically do whatever we want within reason”

Medicare does not require preapproval so you can always do you what you want within reason. But they can come back later and say your treatment was not necessary. At the first level of appeal they’ll use Evicore or local coverage criteria. At independent review they might use ‘standard criteria’ which require the treatment to be furnished in accordance of accepted standards - which might be subjective.

Bobby - yes NCCN addresses SBRT for oligometastases but not for oligoprogression.

 

[deleted18755]

Thanks for the information and clarification everybody. I wouldn’t mind opening up the discussion to anything to do on this topic (I really enjoyed the T cell/SBRT theory and agree it could just be totally made up or completely plausible).

Be really careful with “the patient has Medicare so we can do whatever we want!” That’s almost like saying “isn’t it great how you can do put down whatever you want on federal taxes and the government just accepts it and sends you a rebate check!”

Everything is subject to audit years later and the exact Evicore, NCCN guidelines, ASTRO documents etc are used to benchmark and you might be asked for a lot of money back!!!

 

[medgator]

Everything is subject to audit years later and the exact Evicore, NCCN guidelines, ASTRO documents etc are used to benchmark and you might be asked for a lot of money back!!!

And if it looks egregious/willful, wouldn't be surprised if you get nailed for fraud/treble damages.

Despite (or I should say particularly because of) practicing in FL, I am very detailed in my medical necessity notes when doing any imrt for palliative cases (putting in dose constraints etc that cannot be met via 3D for a given dose) and I make sure my dosimetrist generates a 3D plan to compare which is "rejected" in the system.

I do it exactly in case of the scenario you've outlined above

 

[Krukenberg]

SBRT for oligometastatic dz progression is what I use. I agree with Evicore, actually (shudder), in that there really isn't any good data for XRT use for abscopal stimulation yet, due to the academics failing us. Hopefully soon.

I don’t think it’s accurate that academics are not working on this. If you go to clinical trials.gov there are tons of phase I and IIs going on testing every permutation and sequence of CPIs and RT. I’d even go so far as to say this concept is over-hyped in academics. the first two phase IIIs ever were presented at ASCO. one (HNSCC) was negative and the other (NSCLC) was positive.

 

[Palex80]

Is it that hard to "claim" that the lesion is symptomatic? Pretty much any bone lesion can hurt, can it not?

Of course it wont be that easy if you wanted to SBRT liver or lung, but bone should be doable...

 

[seper]

Can someone please clarify (hopefully from a firsthand experience) financial risk to the patient and legal risk to the physician of billing Medicare for an unusual, expensive radiation treatment? For example, bone met SBRT or whole brain IMRT.

 

[medgator]

Can someone please clarify (hopefully from a firsthand experience) financial risk to the patient and legal risk to the physician of billing Medicare for an unusual, expensive radiation treatment? For example, bone met SBRT or whole brain IMRT.

I think it comes down a couple of things

1) is the icd-10 code covered by your regional Medicare provider? Multiple regions all have different policies regarding imrt and sbrt coverage

2) have you documented a medical necessity letter indicating why you are using/billing the technique you are.

I keep a copy of icd10 codes approved by Medicare for imrt and sbrt billing handy. If your code is on the list, it makes things a lot easier.

I've billed Medicare (and received payment) for imrt to bone mets before in an area which received previous treatment. The icd10 code was on the list anyways but I still documented a medical necessity as to why in case of an audit

 

[evilbooyaa]

evilbooya- when you say “ a lot of the patients we do this on are Medicare, for which my institution has free reign to basically do whatever we want within reason”

Medicare does not require preapproval so you can always do you what you want within reason. But they can come back later and say your treatment was not necessary. At the first level of appeal they’ll use Evicore or local coverage criteria. At independent review they might use ‘standard criteria’ which require the treatment to be furnished in accordance of accepted standards - which might be subjective.

Bobby - yes NCCN addresses SBRT for oligometastases but not for oligoprogression.

As a current resident, I am shielded from this kind of stuff on the back-end. However, I look forward to seeing what proportion of what is billed ends up as collected wherever I end up. If I'm allowed to be privy to it of course! But that's a discussion for another thread.

Having said the above, and in addition to whatever effect fraction size may have on antigen presentation, one further reason why very SBRT-like/hypofractionated regimens might be be more effective at potentiating an abscopal effect: generating an abscopal effect probably requires immune cell activity within the target lesion. But T cells, etc are obviously radiosensitive. So 30 fx just means 6 weeks of killing off all the immune cells that are trying to respond to the tumor. (All the more if you're treating regional LNs, which presumably also play some role in the anti-tumor immune response) Whereas with SBRT-like regimens, you get in whatever secret sauce RT adds, but do in ~5 fx, so only kill off the earliest T cells, and leave plenty of room thereafter for an immune infiltrate to arrive and an anti-tumor immune response to develop. Of course, that's pure theory--but it does make intuitive sense.

When we do non-SBRT in this situation, it's still palliative dosing (30/10 or 20/5 mostly). I wouldn't put somebody through 6 weeks of RT just to stimulate the abscopal effect. Again, I think it's partially handwaving, but I agree that there is at least a radiobiological basis for it. My comment was more on the "higher doses per fraction = better" argument that some proponents of SBRT in this space like to proclaim.