Linac based repeat srs dose

[Mandelin Rain]

1 progressive lesion of many treated melanoma mets. Previous dose 20Gy in 1 fx a year ago. 1.5 cm now with moderate vasogenic edema.

Thinking of fractionated approach. 6Gy x 5 or 9 Gy x 3. Any consensus?

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[Gfunk6]

For re-irradiation, I try to use 9 Gy x 3 fx for salvage after single fraction failure. Try to keep V18 as low as possible, ideally less than 5 cc if you can get away with it.

 

[Neuronix]

1 progressive lesion of many treated melanoma mets. Previous dose 20Gy in 1 fx a year ago. 1.5 cm now with moderate vasogenic edema.

Thinking of fractionated approach. 6Gy x 5 or 9 Gy x 3. Any consensus?

No consensus. My first choice would be surgery to confirm growth of disease as opposed to RT necrosis. If you're convinced or resection is not feasible I would do 6 Gy x 5.

 

[Mandelin Rain]

Spect MRI most consistent with tumor. Patient obviously doesn't want surgery (who does?).

 

[Ray D. Ayshun]

Spect MRI most consistent with tumor. Patient obviously doesn't want surgery (who does?).

Does LITT count as surgery, presuming the location is okay for it? You get tissue confirmation and treatment for either with minimal invasion.

 

[OTN]

Surgery first, if pt refuses, then 6 Gy x 5 is what I would do

 

[evilbooyaa]

Wake forest has some toxicity data on re-treatment:

Repeat stereotactic radiosurgery as salvage therapy for locally recurrent brain metastases previously treated with radiosurgery - PubMed

OBJECTIVE There are a variety of salvage options available for patients with brain metastases who experience local failure after stereotactic radiosurgery (SRS). These options include resection, whole-brain radiation therapy, laser thermoablation, and repeat SRS. There is little data on the...

pubmed.ncbi.nlm.nih.gov

Plan for say 18x1, evaluating minimization of composite V40 with previous treatment, then after plan is completed, change prescription to 9x3 would be my go-to.

 

[Lamount]

At a few places that I have worked, we had NSG use LITT in these circumstances... with the added benefit of obtaining a biopsy to determine necrosis vs. recurrence.

 

[BobbyHeenan]

This clinical case is becoming more common. I swear pre immunotherapy I never saw this. Everyone died a year later.


All I can say is get the bevacizumab ready. Works like a charm when you’re scratching your head on necrosis vs progression 3 months later.

 

[evilbooyaa]

This clinical case is becoming more common. I swear pre immunotherapy I never saw this. Everyone died a year later.


All I can say is get the bevacizumab ready. Works like a charm when you’re scratching your head on necrosis vs progression 3 months later.

Had one patient with steroid-refractory necrosis (like 8mg BID kept her symptoms in check but couldn't wean her off at all), who refused surgery (as she'd already had at least 2-3 resections) and finally convinced a med-onc to give the Avastin. The low-dose Avastin worked like a charm. Wish it wasn't so painful to convince med-onc/neuro-onc to give it.

 

[radoncgrad2019]

It depends where you are. Med oncs are happy to give it for necrosis in my experience

 

[Mandelin Rain]

The discussion of necrosis as a foregone conclusion has me bummed.

 

[evilbooyaa]

I mean it's not 100% but probably closer to 20-30%, which is not nothing.

Sorry to clarify - I mean the risk of necrosis after you re-treat this. Melanoma brain mets not having 100% success rate to SRS is not unexpected.

If you're not convinced it's necrosis now, then reasonable IMO to re-treat.

 

[Ray D. Ayshun]

The discussion of necrosis as a foregone conclusion has me bummed.

Seems like a reasonable time frame for failure, even though the others are stable. At the same time, if something got 20 gy x 1 and possibly grew back, maybe something before/in addition to rt is the right step.