smallest sarcoma

[xrt123]

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Got a guy with Grade 2 myxoid liposarcoma, 2.5 cm in greatest dimension, medial mid thigh. The surgeon had to reoperate because he thought the tumor was an enlarged lymph node. 0.2cm closest margin on reoperation. MSKCC Nomogram says recurrence risk is <10%. Would you treat or close surveillance acceptable?

 

[Neuronix]

You didn't give us an age, but I'll assume they're young. I think 10% is an underestimate. These myxoid liposarcomas are diffusely infiltrating tumors that have a high propensity for local recurrence.

2 mm margin is too close. Why was the margin so close? Is this a sarcoma surgeon or a community guy who almost never cuts on sarcomas?

 

[Cancerdancer]

Lack of upfront well-done oncologic operation is a risk factor for recurrence. I'd treat.

 

[xrt123]

45 yo, community doctor, never cuts on sarcomas.

 

[rymd]

45 yo, community doctor, never cuts on sarcomas.

Then I'd for sure treat.

 

[evilbooyaa]

Can patient go to nearest academic center or see a local surgical oncologist to get an oncologic resection with widely clear margins without excessive morbidity? 0.2cm margin where? If it's deep then it may be hard to re-resect, but if it's sup/inf there could be room for re-excision.

I agree that myxoid liposarcoma != well-diff or even de-diff liposarcoma.

If no possibility of re-resection, then yes, I would at least offer treatment.

 

[xrt123]

The closest margin was the deep margin and "no closer than 15mm" according to path. The 2nd resection was an oncologic surgery with good exposure. He has plenty of more room for reexcision since this was sitting in the subcutaneous fat like a standard lipoma.

 

[evilbooyaa]

The closest margin was the deep margin and "no closer than 15mm" according to path. The 2nd resection was an oncologic surgery with good exposure. He has plenty of more room for reexcision since this was sitting in the subcutaneous fat like a standard lipoma.

15mm? That's 1.5cm, that's more than enough margin.

If you meant 1.5mm, then yes, ideally he'd go for re-re-excision. If the surgeon did 'oncologic' principles, maybe he can go carve out another 1/2 to 1cm of deep tissue.

 

[xrt123]

Sorry. Yes I meant 1.5 mm. Thanks for all of responses. I really appreciate it.

 

[Neuronix]

The problem is that these are diffusely infiltrating tumors. They crawl right through all that subcutaneous fat in all sorts of funny zig-zags with little resistance from the normal adipocytes.

I would refer to an experienced sarcoma surgeon. Even the best surgeon could easily do another surgery and get another 2 mm margin. This is where an experienced surgeon counts. Is it really worth doing the surgery given the tumor, its location, its imaging, etc to possibly avoid RT when there's a good chance you're going to come back with residual microscopic tumor and close margins anyway on the re-excision and still need RT.

Without that, I'd radiate for sure. Don't skimp on the margins. RTOG 0630 is probably ok, but I'd treat with the larger fields. Would strongly consider boost to 66 Gy around the cavity for close margins.

 

[RadOncDoc21]

The problem is that these are diffusely infiltrating tumors. They crawl right through all that subcutaneous fat in all sorts of funny zig-zags with little resistance from the normal adipocytes.

I would refer to an experienced sarcoma surgeon. Even the best surgeon could easily do another surgery and get another 2 mm margin. This is where an experienced surgeon counts. Is it really worth doing the surgery given the tumor, its location, its imaging, etc to possibly avoid RT when there's a good chance you're going to come back with residual microscopic tumor and close margins anyway on the re-excision and still need RT.

Without that, I'd radiate for sure. Don't skimp on the margins. RTOG 0630 is probably ok, but I'd treat with the larger fields. Would strongly consider boost to 66 Gy around the cavity for close margins.

I wouldn't want to be the 2nd surgeon at this point... too many unknowns while inheriting all the risks and outcomes from the prior surgeon. I think at this point, you get a re-excision and do the most suitable RT and hopefully avoid the "oops" sarcoma cases in the future.

Along the same lines, I'm curious would anyone be willing to treat a patient that is currently receiving RT but decided he wanted to be treated by you instead? I know there are a lot of variables to consider, but overall, I think I would avoid getting involved.

 

[evilbooyaa]

Along the same lines, I'm curious would anyone be willing to treat a patient that is currently receiving RT but decided he wanted to be treated by you instead? I know there are a lot of variables to consider, but overall, I think I would avoid getting involved.

Pretty strongly frowned upon IMO. Lots of factors - how many treatments in is he/she? Will you be able to coordinate sim and start of treatment to be continuous with treatment at outside facility? Will other facility be willing to give up their DICOMs on patient so that you can re-create the field? What if you disagree with how the field is created from the other facility?

Lots of risk for suboptimal radiation dosing by switching mid treatment, either too high or too low. Would highly recommend against it to any patient. If the only alternative is that patient absolutely will not get treatment, that would be one scenario I'd consider it for, discussing heavily that this could potentially affect both toxicity and oncologic outcome.