Incidental renal cell in Stage III NSCLC

[BobbyHeenan]

I’ve done a few kidney SBRT cases.

agree with others as above....

- been sent from uro when IR says no.
- have typically been a tad too big for ablation
- they don’t shrink much at all, but don’t grow either. I’m 3/3 on local control.
- I did have one guy with mildly symptomatic psoas myositis , corresponding to some of his dose spill
- I think with Aus and US we should be able to get an SBRT vs IR trial . Probably a pipe dream though.

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[Neuronix]

I've also treated a few kidney masses. Can't imagine doing without MRI adaptive. Target moves a lot with respiration and mobile bowel moves a lot around that area, sometimes next to kidney mass, sometimes not. Dose 50/5, tight margin. Excellent control and no toxicity so far.

 

[ramsesthenice]

I've also treated a few kidney masses. Can't imagine doing without MRI adaptive. Target moves a lot with respiration and mobile bowel moves a lot around that area, sometimes next to kidney mass, sometimes not. Dose 50/5, tight margin. Excellent control and no toxicity so far.

Using MRI is my preference to keep margins as small as possible. That said, I have been doing it a lot longer than I have had an MR linac and many of the patients I treat are too "robust" to squeeze into an MR with a body coil (which is why they are not doing surgery in the first place). Aside from a drop in unilateral renal function (you have to do a split scan to know this) I don't think I have ever seen any notable toxicities. I don't regularly do slit scan either but have done them for a few prospective trials specifically addressing renal function post SBRT. I've done the Cold Spring 13x3 regimen but more typically do 45-50 in 5. As you eluded to, you do have to be selective with anterior lesions because of bowel and everyone needs a 4D. The kidneys can move a lot. Abdominal compression needs to be used with discretion. For posterior lesions it can be helpful to limit the ITV volume (and hence reduce normal kidney dosing) but for anterior lesions it often just squishes bowel down into the kidney. Respiratory gaiting can be a good option too.

 

[Neuronix]

This is the problem with CBCT based guidance for these cases--I'm not convinced that you can see bowel that migrates next to mass or away from mass on a day to day basis. I don't feel comfortable that I can see that on Truebeam or Ethos.

Real-time high quality image guidance is key as well. Keeping PTV super tight generally allows you to significantly lower renal dose. Around the mass I'm sure that you lose some function and this can be demonstrated on advanced kidney scanning. So, the tighter your plan (i.e. smaller the PTV), the more kidney function the patient gets to keep.

 

[ramsesthenice]

This is the problem with CBCT based guidance for these cases--I'm not convinced that you can see bowel that migrates next to mass or away from mass on a day to day basis. I don't feel comfortable that I can see that on Truebeam or Ethos.

Real-time high quality image guidance is key as well. Keeping PTV super tight generally allows you to significantly lower renal dose. Around the mass I'm sure that you lose some function and this can be demonstrated on advanced kidney scanning. So, the tighter your plan (i.e. smaller the PTV), the more kidney function the patient gets to keep.

You 100% can't see the bowel with any confidence using on board CT imaging. I have not personally used ethos but from the demo images I have seen I highly doubt I would feel confident even with it. You have to select for patients who on a 4D scan you don't have bowel within or right on your PTV margins. As I said before, I have never seen a significant bowel toxicity doing it this way. Have also never seen any clinically significant renal toxicities either (with CT or MR based). Again, I am choosy about who I treat.

 

[cpants]

Late to the party, but agree with a urology referral.

From a urologists perspective, in this situation I would likely watch this lesion +/- biopsy only if it would change lung cancer management if it were a met. Assuming it is a RCC, metastatic potential is very low for a tumor this small. This is a good situation for active surveillance and maximizing his renal function to help him fight his lung cancer.

If and when the lung cancer is well controlled he would be a candidate for continued surveillance vs. partial nephrectomy vs. cryoablation. I do not see any good reason to consider SBRT which is not SOC. The gold standard is partial nephrectomy, and cryotherapy is also a very good option with less risks but modestly higher risk of local recurrence.

 

[Ray D. Ayshun]

Just to close this one out, here's the original fused PET, (CT i showed before).

Biopsy found benign renal tissue with fibrosis and chronic inflammation...

Much ado about nothing. Nonetheless, my original question was more of a discussion generator/philosophical approach should it turn out to be RCC in patient with stage III NSCLC.