Largest size you'd do SBRT for

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XRT_doc

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What's the largest size tumor you would do SBRT of the lung for? It's a peripheral nodule close to the ribs. What dose would you use for large lesions?
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3-4 cm. I think once you get above a 7 cm (T3) lesion, you may have better control with chemo rt.

In the middle, I'm not really sure, haven't had that case, but they don't do well.

http://www.ncbi.nlm.nih.gov/pubmed/24210082

The larger and larger the tumor gets, the more hypoxia you have to overcome
 
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I don't wont to brag, but I've done bigger... :joyful:

01de745.jpg


5 x 7 Gy on the PTV-encompassing 60% isodose, 5 x 11.67 in the isocenter.
 
I think anything up to 7cm is somewhat fair game, depending on situation, constraints, etc. It may get dicey close to 7cm. I don't necessarily agree with the reasoning of giving concurrent chemoradiation for the purpose of it treating systemic micromets. The concurrent chemoradiation trials tend to suggest that the benefit is mostly locally anyways.

My take is that SBRT probably still gives better local control if feasible. If you are concerned about systemic failure, give them neoadjuvant or adjuvant chemo, more like a surgical paradigm.
 
the problem is, safety of chemo after SBRT has not been established

radmonckey said:
I think anything up to 7cm is somewhat fair game, depending on situation, constraints, etc. It may get dicey close to 7cm. I don't necessarily agree with the reasoning of giving concurrent chemoradiation for the purpose of it treating systemic micromets. The concurrent chemoradiation trials tend to suggest that the benefit is mostly locally anyways.

My take is that SBRT probably still gives better local control if feasible. If you are concerned about systemic failure, give them neoadjuvant or adjuvant chemo, more like a surgical paradigm.
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seper said:
the problem is, safety of chemo after SBRT has not been established
Click to expand...

You are correct in the sense that I am unaware of clean data set of early stage NSCLC patients treated with curative intent with SBRT and adjuvant chemo. However, there are numerous studies involving oligometastatic patients getting SBRT at high doses who have received multiple lines of chemotherapy, in some cases very recently, and who will likely go on additional chemo after. Our local med oncs send us these patients frequently. I have yet to see any concerning major jump in toxicity in these papers, outside of maybe the use of Avastin. For reference, the current RTOG oligomet trial allows SBRT to be given anywhere from 7-21 days after last chemo, and allows re-initiation of chemo 14 days after completion.

Our institution actually started a Phase II trial looking at this exact question in early stage NSCLC. However, you would be amazed at how hard it is to enroll patients on such a trial. It mostly has to do with the fact that anybody who is in good enough shape to get aggressive chemo is likely also a surgical candidate. We may never get great level 1 data in this scenario, but I feel that it is still a reasonable approach in well selected patients, and I also feel that its safety is well represented enough in the literature to be considered off trial.
 
radmonckey said:
I think anything up to 7cm is somewhat fair game, depending on situation, constraints, etc. It may get dicey close to 7cm. I don't necessarily agree with the reasoning of giving concurrent chemoradiation for the purpose of it treating systemic micromets. The concurrent chemoradiation trials tend to suggest that the benefit is mostly locally anyways.

My take is that SBRT probably still gives better local control if feasible. If you are concerned about systemic failure, give them neoadjuvant or adjuvant chemo, more like a surgical paradigm.
Click to expand...
Agree with that. Just like in H&N, the chemo dosing isn't going really have a lot of distant effects, it's really just for radiosenitization (obvious in the larynx preservation trials). I do think control with even SBRT takes a hit somewhere above 5 cm, just not sure where. In a world of unlimited funding and patients that could be accrued to trials, would love to see an RCT of T2b/T3N0 pts getting SBRT vs chemoradiation.
 
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I would strongly disagree with above.
a) Full dose pac/carbo (usually given as consolidation for 2-3 q3 weekly cycles after weekly concomitant pac/carbo) improves overall survival by treating micrometastases. That is evident from adjuvant chemo trials after surgery.
b) Pac/carbo increases probability of radiation pneumonitis. That's true in post-SBRT setting until proven otherwise. My MedOnc would not give chemo after SBRT due to that.

Therefore, for a 5 cm peripheral NSCLC, chemo-rads to 66 Gy/33 fx is superior to SBRT. For centrally located tumors, it's a no-brainer.
 
Look, this is going to come down to stylistic differences and institutional patterns of care. I don't disagree with the way you describe treating these patients and in most situations would do the same. I'm just saying I've seen and done it both ways. However, if you want to continue to argue, then allow me to retort.

A) Concurrent carbotaxol followed by adjuvant carbotaxol is in generally seen by most as an inferior regimen, and is in my opinion used by med oncs to pump in more chemo.

B) There are plenty of adjuvant and neoadjuvant regimens that don't contain the taxane that is likely driving this uptick in pneumonitis. Also how do you know pneumonitis would be worse with SBRT? There was a randomized trial presented at the 2015 Astro Refresher in the lung session looking at SBRT (66Gy in 3fx) vs conventional (70Gy in 35fx) for T1-2N0 NSCLC demonstrating improved pneumonitis rates (34 vs 16%) in the SBRT arm. Why would the pneumonitis rate seen with carbotaxol be so magnified with SBRT vs conventional fractionation when there is less to begin with?
 
seper said:
I would strongly disagree with above.
a) Full dose pac/carbo (usually given as consolidation for 2-3 q3 weekly cycles after weekly concomitant pac/carbo) improves overall survival by treating micrometastases. That is evident from adjuvant chemo trials after surgery.
b) Pac/carbo increases probability of radiation pneumonitis. That's true in post-SBRT setting until proven otherwise. My MedOnc would not give chemo after SBRT due to that.

Therefore, for a 5 cm peripheral NSCLC, chemo-rads to 66 Gy/33 fx is superior to SBRT. For centrally located tumors, it's a no-brainer.
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Except Carbo/taxol with consolidation is not the preferred regimen in medically fit patients (despite the prevalence in the U.S.and rtog) and you typically don't consolidate a cis-based regimen.

I wouldn't do carbo taxol with consolidation if the pt could tolerate cis/vp-16 concurrently, and as radoncmonkey mentioned, you are less likely to have pneumonitis.

And if you want to talk adjuvant chemo after surgery, all of the data is on cis-based doublets and most med oncs will hesitate to substitute carbo in that situation
 
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Cis/Vinorelbin is a good combination given in the adjuvant setting after surgery and proven effective in trials. Why not give that after SBRT?
 
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seper said:
I would strongly disagree with above.
a) Full dose pac/carbo (usually given as consolidation for 2-3 q3 weekly cycles after weekly concomitant pac/carbo) improves overall survival by treating micrometastases. That is evident from adjuvant chemo trials after surgery.
b) Pac/carbo increases probability of radiation pneumonitis. That's true in post-SBRT setting until proven otherwise. My MedOnc would not give chemo after SBRT due to that.

Therefore, for a 5 cm peripheral NSCLC, chemo-rads to 66 Gy/33 fx is superior to SBRT. For centrally located tumors, it's a no-brainer.
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What is this a Med Onc Forum?! All this talk about carbo/taxol, cisplatin.. :) Heh.. Just kidding. Actually.. can you forward some of the data on b) that Pac/Carbo increases radiation pneumonitis.. actually interested in that regarding a project...
 
Unless I'm mistaken, this data is for concurrent only. Do we have the studies for adjuvant or neoadjuvant chemo causing pneumonitis?
 
seper said:
I would strongly disagree with above.
...
b) Pac/carbo increases probability of radiation pneumonitis. That's true in post-SBRT setting until proven otherwise. My MedOnc would not give chemo after SBRT due to that.
....
Click to expand...
This point seems questionable when we are talking about post XRT versus concurrent
 
seper said:
I would strongly disagree with above.
a) Full dose pac/carbo (usually given as consolidation for 2-3 q3 weekly cycles after weekly concomitant pac/carbo) improves overall survival by treating micrometastases. That is evident from adjuvant chemo trials after surgery.
b) Pac/carbo increases probability of radiation pneumonitis. That's true in post-SBRT setting until proven otherwise. My MedOnc would not give chemo after SBRT due to that.

Therefore, for a 5 cm peripheral NSCLC, chemo-rads to 66 Gy/33 fx is superior to SBRT. For centrally located tumors, it's a no-brainer.
Click to expand...

I dunno man - isn't that chemo data for >4cm pretty weak? I can't say I would subject a patient to chemoRT based on size, not unless they were N+. Why not treat with SBRT up front and reserve chemo for salvage if they fail?
Am I an island in that thinking?
 
Recall pneumonitis is possible with taxanes
 
napoleondynamite said:
I dunno man - isn't that chemo data for >4cm pretty weak? I can't say I would subject a patient to chemoRT based on size, not unless they were N+. Why not treat with SBRT up front and reserve chemo for salvage if they fail?
Am I an island in that thinking?
Click to expand...
I think there is a benefit in large tumors. There is good data for chemo rt in stage IIIA/B patients which includes some large t3 tumors in it. Where I trained, our chairman was a big lung guy and he felt that the really large tumors probably did better with chemo-rt maybe with a little hypofx rather than sbrt alone.

Again, it would be a great study question, but likely something that won't be addressed in the t2b/t3n0 population
 
somewhat of an annoying situation. Got a guy with just outside of central left lung T1a NSCLC that the plan is for SBRT. He has heart failure and is accumulating an effusion on the ipsilateral lung (effusion is unilateral). At time of sim the effusion is actually reasonably large and since he is lying down it is pooling behind where the lesion to be treated is.

I had a concern that I may not be able to see this on CBCT but most likely we will. Physics is concerned though bc of heterogeneity issues (cant really override this as air if its going to be present). Would you send the guy to get drained?
 
If you move on to start SBRT fast enough, effusion should not change dramatically, and not alter your dose distribution.
However, I would personally consider a possibility of a malignant effusion.
 
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medgator said:
Yes although the cytology can be low yield. If the pt keeps on recurring with effusions, prob malignant
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Its just a T1a though? It is weird that it is unilateral don't get me wrong but really, malignant effusion in a T1a? I don't see anything else suspicious by PET?
 
Naturally, will need to re-sim after thoracentesis
 
On the other hand that effusion may actually make your lung DVH look nicer...

I'm not advocating not to drain it. I have however treated patients with stable effusions.
 
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