Lung SBRT Reirradiation

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thaddeus

thaddeus

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I've got a case of an 80yo F with good PS but non-operative candidate with a new stage I NSCLC within 1-2cm of a previously treated early stage NSCLC (50 Gy in 5 fractions in 2013). Original site shows no evidence of recurrence, and the lesion is clearly distinct from the old treatment site and with a spiculated appearance, so fairly convinced this is a new primary instead of a regional recurrence.

The lesion is very peripheral (chest wall adjacent), so I am inclined to do another course of SBRT given that 1) this is her only option for curative treatment and 2) the main toxicity I am worried about is chest wall, which would not be life threatening. I should be able to keep the no-fly-zone to very low dose. Would love to get ideas on both dose/fractionation (I'm thinking something slightly more protracted i.e. 60/8 or 70/10) and any constraints that could be of use in the reirradiation setting. I did a lit search and didn't find much useful. Thanks for your collective wisdom.
 
Honestly, a 5 year gap should be enough time for the fracture risk to return to what you'd expect for first-time SBRT in an 80yo lady (which is still very high), but the costal nerves have longer memory. I would push the dose away from the previously treated CW exposure. Honestly, 70/10 is a huge BED (especially since NSCLC probably has a lower alpha/beta than what was historically regarded), and probably overkill in an 80 year old.

50/5 or 52.5/5 again is probably very safe as long as you respect the region of the CW that was previously treated (and the brachial plexus if it's an upper lobe lesion).
 
thanks for the response, emt409. Fortunately away from plexus...
 
50 / 5 sounds very good. We generally prescribe that to a lower isodose (60-80%).
 
Would hit it with Joe Chang 70/10 regimen. Good PS. Never look at age.
 
absolutely 50/5.

saw one case chest wall blow out with 70/10. have not seen anything bad with 50/5 yet
 
Guys I have a second case for your consideration:

79F NSCLC. She originally presented with a RUL nodule which was abutting the right paratracheal region treated with linac-based SBRT in June 2017 (50 Gy in 5 fractions) with breath hold + VMAT.


Due to comorbidities, she is not a candidate for cytotoxic chemotherapy and she declined all surgery options.


About one year later, she recurred just inferior to the SBRT field in the ipsilateral subcarinal region. PET/CT + MRI Brain negative for disease elsewhere. Her performance status is good ECOG 0.


I can ask one of our local pulmonologists to place fiducial transbronchially. Do you think we can treat her with CyberKnife and, if so, what dose fractionation would you employ? Can also do IMRT with CK MLCs if you think gentler fractionation is helpful.
 
Subcarinal? Is this a lymph node then? Was the initial thing a lymph node? I mean if only site of disease then OK you can entertain it, but you're just playing whack a mole if she had a lung nodule and now has a N2 lymph node.

34/5 at edges, heating up to 40/5 (as feasible respecting tracheal constraint) would be my go to. Obviously get outside plan and ensure overlap isn't outrageous.
 
Oh, OK. Re-treat with 50/5 or 60/8 or whatever your central dose is, keeping track of previously treated lung and constraints (V20, MLD, whatever you prefer to look at for SBRT evaluation) like above in that case. Would still be cognizant of trachea and prox bronchial tree constraints within reason.
 
Gfunk curious if you have a picture, would be interested to see what’s being referre to better. Sounds like you guys evilB too are more risk tolerant than us, 5/50 to an area close to prior treatment centrally feels like a bit much. I Would give options in this case of various RT options and consent based on that
 
the machine you're going to use is irrelevant. idk why anyone would put someone through fiducal placement though.

it's simple. SBRT re-tx - would lean towards 60/8 or something bt of course depends on what the overlap is if you can get away with 50/5 because of minimal central airway ovelap and the dvh looks good, fine. but going with 60/8 seems like an easy enough safe call.
 
Agree that it's hard to really quantify without seeing the distance between lesions, how much overlap there would be, etc. We'd probably balk at re-irradiation with 5 fraction too especially if close to proximal bronchial tree, and do something like 45/15.

I don't have access to Cyberknife, so agree with not bothering with fiducials, but that's my bias as to whether an additional invasive procedure is really worth it.
 
2014XRT said:
the machine you're going to use is irrelevant. idk why anyone would put someone through fiducal placement though.

it's simple. SBRT re-tx - would lean towards 60/8 or something bt of course depends on what the overlap is if you can get away with 50/5 because of minimal central airway ovelap and the dvh looks good, fine. but going with 60/8 seems like an easy enough safe call.
Click to expand...

evilbooyaa said:
Agree that it's hard to really quantify without seeing the distance between lesions, how much overlap there would be, etc. We'd probably balk at re-irradiation with 5 fraction too especially if close to proximal bronchial tree, and do something like 45/15.

I don't have access to Cyberknife, so agree with not bothering with fiducials, but that's my bias as to whether an additional invasive procedure is really worth it.
Click to expand...

I believe the pro of treating with CK with fiducials would be tumor tracking during Tx via fiducials by the CK arm/machine. The proponents believe in it, the doubters bring up the potential issue of fiducial migration (which would probably be less of a risk in central soft tissue vs lung, I imagine).
 
Outside of the scope of this thread, but is that really better than standard 4DCT for tx planning and breath hold CBCT? and Respiratory Gating as necessary?
 
Cyberknife requires fiducial placement

Fiducial placement is not needed for lung.

Thus, Cyberknife for lung SBRT is sort of silly.

I think people who haven't done a ton of linac SBRT (like the Edge) for lung don't get it. If I was a patient I would never want to get fiducials placed for no ****ing reason.
 
evilbooyaa said:
Outside of the scope of this thread, but is that really better than standard 4DCT for tx planning and breath hold CBCT? and Respiratory Gating as necessary?
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The pro-Accuray folks would say yes, the pro-Varian folks would say no. I have no idea, I am sure there are plenty of riveting and non-helpful papers on the matter.
 
Thanks for input. We have linacs that can do SBRT using high-def MLCs with VMAT and 4D planning CT + 4D CBCT with breath hold. That is how this patient was originally treated.

Current version of CK allows fiducial-less tracking in 70% of cases in lung. In the 30% which can't, makes more sense to convert to linac based SBRT as above.

However with tracking you can generate GTV + 3 mm margin to get your PTV and that's all you need. Minimal volume of normal tissue in treatment field is key in re-irradiation cases like this.

Here is screenshot for anatomic reference:

upload_2018-5-10_16-45-55.jpg
 
I'd do 50gy in 10 fx. Wake forest has published this as reirradiation regimen after prior sbrt. Given the central location and prior adjacent sbrt, Anything more hypofractionated would make me nervous.

agree that fiducials unlikely to provide benefit. Would be surprised if motion is greater than 5mm
 
medgator said:
I really wish we had some chemo/XRT vs SBRT data in situations like this. If this was an upfront situation, I would offer that pt chemo-radiation
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That was our first inclination too but patient is pulmonary cripple with multiple co-morbidities - Med Onc ruled out chemo. Interestingly five years prior to diagnosis she underwent lung volume reduction surgery (Lung Volume Reduction Surgery (LVRS) | Cleveland Clinic).
 
40Gy/5fx. Still a good BED. If it’s inferior lesion, use VMAT or 9 coplanar IMRT fields with breath hold and dose should not overlap.

She’s old with bad comorbidities. Be conservative. No need to fractionate more than 5fx though.
 
medgator said:
Debatable. 70/17 has a good BED and fractionation can be your friend in a re-tx scenario
Click to expand...

There's nothing wrong with that fractionation, but personally I'd rather treat her with a safe SBRT dose where I can minimize treatment volume with triggered imaging, and get her done with treatment as soon as possible. I'd probably talk to her pulmonologist about a steroid taper as well.
 
emt409 said:
There's nothing wrong with that fractionation, but personally I'd rather treat her with a safe SBRT dose where I can minimize treatment volume with triggered imaging, and get her done with treatment as soon as possible. I'd probably talk to her pulmonologist about a steroid taper as well.
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Really though? who cares about an extra 2 weeks. This is not a palliative situation. We’re conservative, 5 fx for this is made more risky by the fact that it’s carina, damage there isn’t just 1 lung, it’s both. We’re afraid to even drop 1 lobe in a pulm cripple like this
 
Haybrant said:
Really though? who cares about an extra 2 weeks. This is not a palliative situation. We’re conservative, 5 fx for this is made more risky by the fact that it’s carina, damage there isn’t just 1 lung, it’s both. We’re afraid to even drop 1 lobe in a pulm cripple like this
Click to expand...

If you think 70/17 is less toxic than 40/5, especially when your 40/5 treatment will have smaller margins and better image guidance, you are crazy friend. Maybe for alpha/beta of like 1, they might be same BED, maybe....
 
emt409 said:
If you think 70/17 is less toxic than 40/5, especially when your 40/5 treatment will have smaller margins and better image guidance, you are crazy friend. Maybe for alpha/beta of like 1, they might be same BED, maybe....
Click to expand...

Ah ok the comparison was 70/17. We don’t mess too much w the nonstandard fractionations, too much risk but that doesn’t make it wrong. 300 x 15, 200 x 30 is safe.
 
Last edited:
Can someone link this 70/17 data? Never heard of that fractionation. Heard of 54/3, 60/5, 50/5, 60/8, 48/4, 45-60/15, etc, in terms of hypofractionated regimens.
 
I think 70/17 is too much for central tumors, and I've seen one case of resultant confluent, symptomatic fibrosis
 
im confused. 70/17 is far less BED than 50/5 - how could that be considered unsafe for a central tumor when 50/5 is standard central tumor dose?
 
xrthopeful said:
im confused. 70/17 is far less BED than 50/5 - how could that be considered unsafe for a central tumor when 50/5 is standard central tumor dose?
Click to expand...

I'm still in the skeptical camp about 50/5 for very central lesions, there are def reports of central airway necrosis with this dose and fractionation. Do most of you feel differently? Maybe it doesn't make any sense, the BED numbers are pretty similar, but I will do the dutch 60/8 for more central lesions with an SBRT setup in these patients (though obviously can't bill for SBRT).
 
No set interval for me, I've found that 50% PET-diagnosed SBRT recurrences show inflammation on biopsy or resection. So I always try to re-biopsy before re-irradiation.
 
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