Reflexion - BgRT

[Gfunk6]

I heard a presentation yesterday from Reflexion - they have built an integrated Tomotherapy + PET unit to perform what they call "biologically-directed therapy" or BgRT. I am happy to answer questions about it on this thread.

Two things which stood out from the presentation is that the entire concept of BgRT is predicated on two large assumptions (supported by preliminary research but not validated in large trials):

1. SRS/SBRT + Immunotherapy = abscopal effect = better patient endpoints than either approach alone
2. Ablation of cancer in patients with "polymetastatic" disease (e.g. > 5 mets) will improve relevant endpoints like OS

Also, you get a PET scan prior to the delivery of ablative treatment on the Reflexion. The system is adaptive in the sense that it will treat a larger area (predefined by the MD) if the positron emission of the target is larger than during the CT sim. However unlike most systems which require manual intervention (e.g. MRI-guided linacs) for any such adaptation, the Reflexion does it automatically based on the company's algorithms plus MD presets. This is both amazing and terrifying to me.

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[Doctorer]

I’ve heard of this but it seems... kind of dumb? It’s unclear to me as to what makes this better than fusing a pet to a regular treatment planning scan and then treating them on a tomo/linac/halcyon/etc.

 

[Mandelin Rain]

I’ve heard of this but it seems... kind of dumb? It’s unclear to me as to what makes this better than fusing a pet to a regular treatment planning scan and then treating them on a tomo/linac/halcyon/etc.

Correct me if I'm wrong, but it I believe automatically generates an adaptive plan based on the pre-treatment PET based on SUV cutoffs and AI based contouring of OARs.

It's almost like a 4 year residency wouldn't be needed to operate such a thing.

 

[radoncgrad2019]

wake me up when FDA approved. Been hearing about this since Fall 2017 now. not ready for prime time IMO

 

[OTN]

Trying to answer a question no one asked. Three main problems with it that I can tell:

1. Lack of data showing benefit to treating > 5 mets.
2. Data shows there is NOT an SUV cutoff which is reproducible between patients for a given tumor type. Data shows the opposite in NSCLC.
3. No one has yet to be able to tell me how this is fundamentally any different than: PET scan for planning --> fuse to CT sim --> plan as we normally do --> treat as we normally do.

Of all the new machines we've seen developed over the course of the last two decades, this is the dumbest by an order of magnitude.

 

[BobbyHeenan]

It's like someone said - "hey, imagine if we could use real time PET data to help target or treat patients with an integrated PET/Linac" and everyone got a physics boner. But then no one said "but why would we? or how is this different than just fusing the CT sim to PET?"

 

[medgator]

Reflexion > viewray > Tomo my guess in terms of bk risk

Sounds like the provenge of treatment planning and delivery

 

[Lamount]

I am not quite at a place where I am ready to let the robot prescribe high dose radiation in my name...

 

[scarbrtj]

I do radiobiologically directed therapy.

 

[Palex80]

One concern that I have is that immunotherapy can enhance PET uptake itself. Thus the Reflexion may start treating a larger area thinking it‘s tumor, while it‘s merely inflammmation around the tumor.

 

[thecarbonionangle]

The device is going to be treating your PTV, your contour not the FDG. The FDG is solely used as a guide for movement “fiducial”-like

 

[SubserviantToABR]

I envision BgRT as the future. At my local car wash, I buy a monthly car wash pass and can wash my car as often as I want each month. Why can't we do the same with oligomets? Just run the patient through the Reflexion whenever they please, and the machine can treat any new met without any human intervention. No need for four years of residency to learn planning, treatment delivery, and patient management. We can focus on other things that patients need, like a wheel polish and interior detail. In sales, we consider that upselling, like an extended warranty or SiriusXM subscription. I can upsell them things like a colostomy once that machine screws up, misses its target, and ablates a loop of bowel. That's the future of the radiation oncologist...upselling customers, I mean, patients, while we let machines and academic chair overlords put us out of practice.

 

[radoncgrad2019]

You just made us all dumber for having read that

 

[SubserviantToABR]

You just made us all dumber for having read that

At least I'm not trying to sell you something. It's only dumb if people are out there planning on buying the Reflexion. Now, if you excuse me, I have to go generate RVUs for my unappreciative chair for mediocre academic junior faculty pay. Lucky for him, there's no bonus structure in my appointment. Welcome to rad onc.

 

[radoncgrad2019]

I will say that a lot of people are going to be embarrassed they ever even let Reflexion come pitch to them, let alone buying their machine.

It’s a chump machine, for chumps

 

[deleted941485]

They presented at our institution. Admittedly I was amused and interested at 10 minutes in and then by the end of the presentation I realized that it’s probably a waste of departmental money and time. Physicists seem pretty hell bent on automating every aspect of the job. Which sort of makes my laugh. It seems nobody told them that automation is a double edge sword. Plus idk about other places but here they are simply an insufferable bunch.

 

[xrthopeful]

Just give me a good Varian Edge and that's all we need in life, baby

 

[radoncgrad2019]

Just give me a good Varian Edge and that's all we need in life, baby

Can do anything and everything

 

[medgator]

Can do anything and everything

Edge is pretty much an srs/srt machine isn't it? Just give me a Truebeam, personally. I can run my entire clinic on one machine

 

[radoncgrad2019]

Yeah either. truebeam fantastic

 

[thecarbonionangle]

the part that is pending FDA approval (Steve Hahn soon?) is BGRT. They do not have animal or human data just phantom data. The machine is basically a tomo unit but instead of MV CBCT it has KV CBCT. So anybody thinking about buying it before FDA approval would still get a treatment machine out of it, high price, but it would not be totally useless. Who knows how long BGRT will take. Will be interesting to see where this ends up, if at all...

i know there are differing opinions on MR linacs but multiple departments are now buying them..

 

[radoncgrad2019]

I can see the advantage of MR Linac. It's very resource intensive, but it serves a purpose. Has a role in academic centers.

IMO the reflexion is garbage. A solution in search of a problem.

maybe I'll be proven wrong.

 

[evilbooyaa]

It's a cool concept but the necessity of real-time SUV monitoring is controversial. Wherever it ends up they'll be able to publish (IMO) worthless research articles about the 'feasibility' of it, so it's cool as a 'research' machine, but is it going to shift the needle for 99% of rad onc departments? No.

There's some bit about using FDG-avidity as a real time tracker to allow for tumor tracking for lung SBRT.... That'd be cool if a static tomotherapy treatment plan could create dosimetry similar to a standard stereotactic linac (TrueBeam, edge, or Versa HD for example)

 

[OTN]

It's a cool concept but the necessity of real-time SUV monitoring is controversial. Wherever it ends up they'll be able to publish (IMO) worthless research articles about the 'feasibility' of it, so it's cool as a 'research' machine, but is it going to shift the needle for 99% of rad onc departments? No.

There's some bit about using FDG-avidity as a real time tracker to allow for tumor tracking for lung SBRT.... That'd be cool if a static tomotherapy treatment plan could create dosimetry similar to a standard stereotactic linac (TrueBeam, edge, or Versa HD for example)

In the current APM environment, using FDG-avidity as a biologic real-time tracker is more or less DOA, however.

 

[Gfunk6]

In the current APM environment, using FDG-avidity as a biologic real-time tracker is more or less DOA, however.

For what it's worth, leadership of Reflexion thinks that he technology is unique enough that it will be exempt from APM. TIme will tell.

 

[deleted941485]

In the current APM environment, using FDG-avidity as a biologic real-time tracker is more or less DOA, however.

In the current APM environment my incentive is to get pts on treatment and then kick them out the door as quickly and as cheaply as possible.

 

[wandering star]

Two things which stood out from the presentation is that the entire concept of BgRT is predicated on two large assumptions (supported by preliminary research but not validated in large trials):

1. SRS/SBRT + Immunotherapy = abscopal effect = better patient endpoints than either approach alone
2. Ablation of cancer in patients with "polymetastatic" disease (e.g. > 5 mets) will improve relevant endpoints like OS

I work in physics and overlapped with the founder of Reflexion when he was still going to school. I took some of the same classes that he did on startups.

The first thing you need to know is that Silicon Valley is not about "what probably works." Silicon Valley startups operate in this fantasyland "go big or go home" principle. Empirically, it has long been observed that a venture capital firm might gives $1 MM each to 10 companies. 7 will fail outright, 2 will break even, and 1 will return 10x. Every firm is funded not on its likelihood to break even, but on its potential to be the 10x winner. Whether you agree with this or not, it is a reality that the ecosystem of Silicon Valley is set up so that to fund companies that both have large bankruptcy risk (e.g. 70%) but also have very large upside potential.

The second thing you need to know is that business opportunities are created by change. Without change, there is rarely opportunity. So you see where the field is going, you get ahead of it, and once the world gets there you are ready to claim all the territory. For example, smartphone use is exploding >>> let's create a rideshare service. It may not be practical YET, but with if trends continue it will one day be inevitable. Often you extrapolate wrong and you go into bankruptcy. Other times you win big. That is the Silicon Valley MO.

The trend here, if I had to guess, is treatment of oligometastatic disease. Remember that Reflexion picked this strategy *before* SABR-COMET was published and all the associated trial data appeared. Around this time I would ask my rad onc colleagues -- can you understand what they are doing? And almost universally they would say, they are crazy, no one treats metastatic disease, if that was possible wouldn't we know by now?

Today we are one step closer. We still don't have data data for "polymetastatic" disease and they are taking a substantial risk that this data will never appear (or worse, appears and is negative). I'd like to believe that Reflexion is making a reasonable extrapolation but the rest of us will have to wait and see if their bet pays off. In this light Reflexion looks almost like a drug company that passed Phase I trials and is now bought by Merck to run through the gamut of Phase II/III trials. Plausible data, a new mechanism, worth a shot, but we won't know until we try it out.

For the time being, I think it's fair for outsiders to be skeptical and see how the field develops first.

 

[Gfunk6]

Today we are one step closer. We still don't have data data for "polymetastatic" disease and they are taking a substantial risk that this data will never appear (or worse, appears and is negative). I'd like to believe that Reflexion is making a reasonable extrapolation but the rest of us will have to wait and see if their bet pays off. In this light Reflexion looks almost like a drug company that passed Phase I trials and is now bought by Merck to run through the gamut of Phase II/III trials. Plausible data, a new mechanism, worth a shot, but we won't know until we try it out.

First off, thank you for the thoughtful, excellent post. Very good summary of Silicon Valley culture and putting Reflexion into context.

One point to support what I've quoted above is that pharma companies like J&J have invested millions into Reflexion. The concept is that if SABR works synergistically with immunotherapy then it will increase utilization of the latter.

 

[radoncgrad2019]

Nice post wandering star. I agree that I get why Reflexion exists as a company.


I just wouldn’t want to be the chump who bought a lemon machine when they’re not going to be around in 10 years.

 

[thaddeus]

Alternatively, its very possible that in 10 years we'll all be using FLASH machines and laughing about the foolishness of BGRT, MR Linacs, Protons, and all the rest.

 

[medgator]

Nice post wandering star. I agree that I get why Reflexion exists as a company.


I just wouldn’t want to be the chump who bought a lemon machine when they’re not going to be around in 10 years.

Whatever happened to the VERO? I remember hearing about it a few years ago and then never again... Seemed like a fancy rotating Tomo that was just asking for bugs, like the original tomos seemed to be full of

Innovation in Motion. Think Vero. - Brainlab

The pre-eminent, all-in-one stereotactic system for whole body, Vero represents the latest RT technology offering individualized, non-invasive treatment for cancerous and non-cancerous conditions of the entire body.

www.brainlab.com

 

[anonymuncule]

Edge is pretty much an srs/srt machine isn't it? Just give me a Truebeam, personally. I can run my entire clinic on one machine

what the differences between the two machines?

 

[RadOncDoc21]

what the differences between the two machines?

They are really the same machine except an EDGE is dedicated more for SRS/SBRT. You can actually modify the EDGE to be used like a TrueBeam and vice versa. After speaking with various reps, it would be cheaper overall to buy an EDGE with some limitations on the maximum field size.

 

[medgator]

what the differences between the two machines?

They are really the same machine except an EDGE is dedicated more for SRS/SBRT. You can actually modify the EDGE to be used like a TrueBeam and vice versa. After speaking with various reps, it would be cheaper overall to buy an EDGE with some limitations on the maximum field size.

Yup. That was why we bought a Truebeam instead of a Truebeam stx, didn't want a limitation to 30cm field size. Only downside is we lack the microMLC needed for smaller target srs/srt, but that's an easy trade-off in a general practice imo. I've sent a few 3-5mm lesions out for GK.

Guessing the STX = edge pretty much?

 

[Mandelin Rain]

Yup. That was why we bought a Truebeam instead of a Truebeam stx, didn't want a limitation to 30cm field size. Only downside is we lack the microMLC needed for smaller target srs/srt, but that's an easy trade-off in a general practice imo. I've sent a few 3-5mm lesions out for GK.

Guessing the STX = edge pretty much?

Can't you just get the cones for True Beam?

 

[medgator]

Can't you just get the cones for True Beam?

Seems like a hassle for what is not that many cases requiring them

 

[Mandelin Rain]

Seems like a hassle for what is not that many cases requiring them

I use them a lot, I guess. Pretty much anything up to a centimeter or so gets cone based.

 

[deleted1002574]

Edge gets you through most cases in a community practice.

The things that throw you are PA/Pelvis for cervix, large palliative bone met fields, very large chest wall / nodes.

Either you have a nice backup linac that you need to keep commission, you’re a large system that can send patients out to a partner for that, or a frenemy in town that won’t talk ****.

95-98% of cases work, though

 

[medgator]

Edge gets you through most cases in a community practice.

The things that throw you are PA/Pelvis for cervix, large palliative bone met fields, very large chest wall / nodes.

What's the difference between an edge and a Truebeam STX? Both seem like srs focused machines that can also do field-size limited fractionated treatment

 

[Neuronix]

What's the difference between an edge and a Truebeam STX? Both seem like srs focused machines that can also do field-size limited fractionated treatment

I have been asking this for months now and nobody can seem to give me a straight answer. I have a lot of contacts at Varian so I will ask and find out.

As background, I tell people that you should understand a Truebeam like a car. There's a base model and all the upgrade packages. You can buy them individually or bundle them together. Like a Camry has L, LE, SE, XLE, and XSE trims and lots of little upgrades you can buy, a Truebeam has its STx trim and there are lots of little upgrades that get negotiated when you buy a Truebeam. An Edge is the same base model linac (Truebeam) with upgrade packages as well. They just changed the name of it from Truebeam to Edge kind of like how a Mustang gets changed to a Shelby Cobra.

One commonality between the Truebeam STx and Edge is the HD120 MLC system -- 2.5 mm MLCs in the center 8 cm. But the number of leaves is the same as the less dense leaf systems. This means maximum collimator size is 40 x 22 cm on those systems. You can either accept this and routinely junction large fields (annoying and a little risky), have another machine with a larger collimator, or not buy one of these systems but instead elect for the base model Truebeam with 5 mm MLCs in the center and a 40 x 40cm collimator and use cones for intracranial SRS. Other body SBRT sites can benefit as well from microMLC collimation like spine, but there's an arguable clinical benefit.

This leads me to one of my pet peeves. Just because someone says they're doing something on a "Truebeam" does not mean they have the same Truebeam that you have or are using it in the same way you are. They may be using options packages that you don't have, aren't aware of, or don't know how to use.

 

[medgator]

I have been asking this for months now and nobody can seem to give me a straight answer. I have a lot of contacts at Varian so I will ask and find out.

As background, I tell people that you should understand a Truebeam like a car. There's a base model and all the upgrade packages. You can buy them individually or bundle them together. Like a Camry has L, LE, SE, XLE, and XSE trims and lots of little upgrades you can buy, a Truebeam has its STx trim and there are lots of little upgrades that get negotiated when you buy a Truebeam. An Edge is the same base model linac (Truebeam) with upgrade packages as well. They just changed the name of it from Truebeam to Edge kind of like how a Mustang gets changed to a Shelby Cobra.

One commonality between the Truebeam STx and Edge is the HD120 MLC system -- 2.5 mm MLCs in the center 8 cm. But the number of leaves is the same as the less high density leaf systems. This means maximum collimator size is 40 x 22 cm on those systems. You can either accept this and routinely junction large fields (annoying and a little risky), have another machine a larger collimator, or use a larger collimator with 5 mm MLCs in the center and use cones for intracranial SRS. Other body SBRT sites can benefit as well from fine collimation like spine, but that's an arguable clinical benefit.

This leads me to one of my pet peeves. Just because someone says they're doing something on a "Truebeam" does not mean they have the same Truebeam that you have or are using it in the same way you are. They may be using options packages that you don't have, aren't aware of, or don't know how to use.

And then there is the "VitalBeam" which is basically a stripped down Truebeam that's running on the same newer digital platform as the Truebeam but isn't really equipped for srs/sbrt. Sounds like the newer version of the iX.

Apparently elekta moved from analog to digital awhile ago but this only more recently happened with Varian and the True/Vital beam

 

[deleted1002574]

That’s correct about the nomenclature.

Many, many centers - including ours - says they have Truebeams, when most are actually Edge.

It’s annoying. I didn’t realize I’d have these field size issue.

 

[medgator]

That’s correct about the nomenclature.

Many, many centers - including ours - says they have Truebeams, when most are actually Edge.

It’s annoying. I didn’t realize I’d have these field size issue.

I specifically made sure we avoided getting an STX for that very reason, understanding the trade-off of having a more difficult time with smaller srs/srt cases

 

[Neuronix]

That’s correct about the nomenclature.

Many, many centers - including ours - says they have Truebeams, when most are actually Edge.

It’s annoying. I didn’t realize I’d have these field size issue.

I assume you could buy the HD120 MLC as an upgrade when you buy your Truebeam and have that not officially be called an Edge or STx as well. The MLC is one of the upgrade options when you buy the system.

I also assume this accounts for some docs telling me that X center is doing SRS on their Truebeam, so why can't they do it here with our 5 mm MLC widths? Not that that's the only consideration for intracranial SRS, but you get the idea.

 

[evilbooyaa]

I usually make a distinction between talking about a Truebeam and an STX and an EDGE. Edge seems to me like a newer version of STX FWIW.

I personally don't think STX/EDGE should be the only linac at a center. I would want a regular TrueBeam with the 40x40 field and some other machine that could be the second machine for SRS/SBRT.

I think Trilogy can do big fields too? Would be a reasonable workhose machine for para-aortic extended fields, big palliative cases, and 3-field breasts done with mono-isocenter technique.

 

[medgator]

I usually make a distinction between talking about a Truebeam and an STX and an EDGE. Edge seems to me like a newer version of STX FWIW.

I personally don't think STX/EDGE should be the only linac at a center. I would want a regular TrueBeam with the 40x40 field and some other machine that could.

I think Trilogy can do big fields too? Would be a reasonable workhose machine for para-aortic extended fields, big palliative cases, and 3-field breasts done with mono-isocenter technique.

We use iXs at some of our more low volume sites and send sbrt/srs to the main center.

Afaik, a trilogy was basically a clinac iX with a tighter isocenter and higher dose rate

 

[deleted1002574]

The price difference is substantial. And when you can do 95% of cases (go through your charts and you’ll see how many need 40 x 40 in real world), it will be tough to justify to administrators. I think in real life, the opposite is actually true - “in a community clinic, there is no reason to get the full true beam, because only 2-5% of cases can’t be treated on it”. It’s not that I believe it to be true, it’s how administrators and in the future, investors will see things. ROI, baby.

I usually make a distinction between talking about a Truebeam and an STX and an EDGE. Edge seems to me like a newer version of STX FWIW.

I personally don't think STX/EDGE should be the only linac at a center. I would want a regular TrueBeam with the 40x40 field and some other machine that could.

I think Trilogy can do big fields too? Would be a reasonable workhose machine for para-aortic extended fields, big palliative cases, and 3-field breasts done with mono-isocenter technique.

 

[evilbooyaa]

STX/Edge is cheaper than a regular truebeam? I figured they would be similar in price. In terms of pricing I have zero experience.

 

[deleted1002574]

Big difference. That’s why they are popping up everywhere, and everyone is saying they have a Truebeam, but it’s not true. Can’t blame Varian. They are specific with names.

 

[medgator]

The price difference is substantial. And when you can do 95% of cases (go through your charts and you’ll see how many need 40 x 40 in real world), it will be tough to justify to administrators. I think in real life, the opposite is actually true - “in a community clinic, there is no reason to get the full true beam, because only 2-5% of cases can’t be treated on it”. It’s not that I believe it to be true, it’s how administrators and in the future, investors will see things. ROI, baby.

I probably have more large 4 field breast and extremity patients than I do patients with sub cm brain mets, obviously being subjective here based on my gut feeling. I don't treat (not miss) Trigeminal pts

STX/Edge is cheaper than a regular truebeam? I figured they would be similar in price. In terms of pricing I have zero experience.

I assumed the opposite, I thought the STX would be more expensive with the capability to treat smaller lesions and the 6DOF couch being standard probably etc