Cardiac nodal ablation via SBRT

[Gfunk6]

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Radiation beam to the heart - Outlook Magazine

Finally a positive RO article! Hope that this becomes widespread . . .

 

[Krukenberg]

Radiation beam to the heart - Outlook Magazine

Finally a positive RO article! Hope that this becomes widespread . . .

Given cardiology’s propensity to take what other specialties do and do it themselves I worry about whether ROs will see much of the rewards for this.

 

[medgator]

Given cardiology’s propensity to take what other specialties do and do it themselves I worry about whether ROs will see much of the rewards for this.

Uhhhhh, a linac is harder to do that to than an ultrasound or vascular catheter.

Ever heard of coronary brachy and who had to be present for it?

 

[Fpg1245]

Uhhhhh, a linac is harder to do that to than an ultrasound or vascular catheter.

Ever heard of coronary brachy and who had to be present for it?

We had some cards guys inquire about using SBRT for this a few months back. Seemed willing to do it if logistics were all in place. There was an NEJM article that examined doing this for refractory vtach. There is some interest in it but in all honesty I think it Won’t be enough to move the needle for RO. Plus EP will probably be resistant.

 

[medgator]

We had some cards guys inquire about using SBRT for this a few months back. Seemed willing to do it if logistics were all in place. There was an NEJM article that examined doing this for refractory vtach. There is some interest in it but in all honesty I think it Won’t be enough to move the needle for RO. Plus EP will probably be resistant.

Agree, this will be a niche and certainly not enough to create a ton of demand. But it will belong to RO and no one else imo, in the way that GK and other brain met srs does

 

[OTN]

You guys would be surprised- I’ve met with two huge EP groups in town, and they’re all chomping at the bit to do this. The SBRT VTach data was in patients who were refractory to all other treatments, so they’re naturally excited to have something else to offer.

AFib ablation might be tougher to get into, but in talking with these EP groups, there’s a ton of stuff SBRT could do for their patients. AFib, VTach, ablation of the sympathetic chain, etc. I think we’re just at the start of things with respect to radiocardiology.

 

[evilbooyaa]

Honestly shouldn't be that hard either from a Rad Onc perspective. I mean it's up to the EPs to tell us what to hit, but we can hit it just fine. Glad to see somebody is running for public advertising with the NEJM article.

 

[seper]

I hate to rain on everybody's parade, a point in a beating heart is actually difficult "to hit" with SBRT. Next time you take a 4D verification CBCT for a lung nodule SBRT, take a look at the heart.

Honestly shouldn't be that hard either from a Rad Onc perspective. I mean it's up to the EPs to tell us what to hit, but we can hit it just fine. Glad to see somebody is running for public advertising with the NEJM article.

 

[evilbooyaa]

You really think the motion of a singular spot in a beating heart is more than what? 5mm? 1cm? It's not something that can be controlled for. And most tachyarrhythmias don't start in the ventricular tissue, they're at the AV node or atrial tissue so motion is less of an issue than trying to spot treat something in the left ventricle.

 

[fiji128]

I have seen some thoracic surgery procedures in person (ie lobectomy ect...) the heart actually moves around quite a bit with each beat and then adding lung/diaphragm motion on top of that. I imagine it would very difficult to hit some small spot with any degree of certainty.

 

[Palex80]

I have seen some thoracic surgery procedures in person (ie lobectomy ect...) the heart actually moves around quite a bit with each beat and then adding lung/diaphragm motion on top of that. I imagine it would very difficult to hit some small spot with any degree of certainty.

True, but it depends on what the goal is. Treating 50 year olds, otherwise healthy, therapy naive patients? Or treating 83 year olds, comorbid patients who have undergone other ablation procedures that were unsuccessful?
The first ones wont be the ideal candidates, they may very well be treated otherwise and experience late toxicity of RT. The 83 year olds will however probably die within 10 years or so, so late cardiac toxicity may not be an issue. So... when uncertain of target coverage, open up those MLCs.. .🙂

 

[Radiator20]

In the NEJM paper, the authors note: "Notably, in all patients the portion of the heart being targeted was akinetic or hypokinetic due to preexisting cardiac scar in that region." So that may decrease somewhat the intrinsic motion with cardiac cycle (but not respiratory cycle). That said, I still feel a bit skeptical about target localization here...

 

[seper]

This is a kind of RT treatment for which a placebo-controlled trial is feasible.

 

[nkmiami]

In the NEJM paper, the authors note: "Notably, in all patients the portion of the heart being targeted was akinetic or hypokinetic due to preexisting cardiac scar in that region." So that may decrease somewhat the intrinsic motion with cardiac cycle (but not respiratory cycle). That said, I still feel a bit skeptical about target localization here...

I dont know, the volume seemed really big in the picture- its not trigeminal.

 

[radiaterMike]

In order to justify a placebo controlled trial you would need enough pilot / Phase II data to justify the expense and effort. On the other hand if there is a large difference between treated patients and historic controls, than one would not have equipoise to ethically do a RCT.

 

[Gfunk6]

Placebo controlled trials are not practical for medical devices and are considered unethical by some bioethicists.

 

[emt409]

Given cardiology’s propensity to take what other specialties do and do it themselves I worry about whether ROs will see much of the rewards for this.

Enter CardioRads!

 

[emt409]

You really think the motion of a singular spot in a beating heart is more than what? 5mm? 1cm? It's not something that can be controlled for. And most tachyarrhythmias don't start in the ventricular tissue, they're at the AV node or atrial tissue so motion is less of an issue than trying to spot treat something in the left ventricle.

The v tach patients referenced here have re-entrant tachy arrhythmias due to regions of scarring in the ventricular myocardium. The SBRT essentially homogenizes the scar, thus preventing it from conducting any more and eliminating the re-entrant pathway.

Cliff Robinson, the main rad onc doing it at Wash U, currently uses an ITV, but has an abstract about using MRI guidance.He started with an ITV to account for the motion. The pre-treatment cardiac MR allows measurement of the maximum displacement. It's pretty cool stuff.

AFAIK, the CyberHeart people have been trying to get ablation of the PV down for atrial tachyarrhythmias, but they're probably now looking into this as well.