sarcoma case drain site

[BobbyHeenan]

I have a case of a pT1(4cm)N0MO Grade 2 sarcoma s/p resection by a good surg onc. Margins 4mm in two areas (deep and anterior), 1 mm "superficial" margin that surg onc feels is artifactually close (he took some skin). This was a superficial sarcoma in an obese leg. Just barely touched deep fascia but did not invade into muscle though surg onc took some muscle. Tumor involved saphenous vein and it had to be ligated.

Patient already has some minor distal edema.

I took a cartoon of a sarcoma from a paper and edited. My patients disease/operative bed goes no where close to deep bone so operative bed is in red. in my patient the red surgical bed is superficial. However, the drain is almost medial/midline. A nice little tangent plan will cover the operative bed well, but I'm concerned that if I treat the drain site it will increase lymphedema risk more. Do I have to cover this drain site? Is is worth it to maybe put an electron patch there? Or just forgo it the drain site.

Any thoughts are appreciated.

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[rymd]

My bias is not to treat the drain site in this scenario unless it is within or right next to the CTV. I would just ask the surgeon if they're concerned- otherwise; otherwise, especially based on you're very impressive artwork, I would not end of treating the drain site.

 

[NotMattSpraker]

I have a case of a pT1(4cm)N0MO Grade 2 sarcoma s/p resection by a good surg onc. Margins 4mm in two areas (deep and anterior), 1 mm "superficial" margin that surg onc feels is artifactually close (he took some skin). This was a superficial sarcoma in an obese leg. Just barely touched deep fascia but did not invade into muscle though surg onc took some muscle. Tumor involved saphenous vein and it had to be ligated.

Patient already has some minor distal edema.

I took a cartoon of a sarcoma from a paper and edited. My patients disease/operative bed goes no where close to deep bone so operative bed is in red. in my patient the red surgical bed is superficial. However, the drain is almost medial/midline. A nice little tangent plan will cover the operative bed well, but I'm concerned that if I treat the drain site it will increase lymphedema risk more. Do I have to cover this drain site? Is is worth it to maybe put an electron patch there? Or just forgo it the drain site.

Any thoughts are appreciated.
View attachment 361261

Do you have a more specific histology than sarcoma?

There is no evidence to support treating drain sites. I don't have access to the protocol anymore but I think Sarc032 specifically says do not do it.

Don't bolus and use IMRT as it is now standard.

Also, you should just be aware of this prospective data that shows fairly low recurrence rates for small (<5 cm) superficial sarcomas that are resected with negative margins if you omit radiation. The decision is to omit is of course extremely personalized on a number of factors that aren't included in your description and histology matters a lot. If its a synovial sarcoma in a 25 year old you might not be helping by treating, if its a myxofibrosarcoma in a 60 year old you're probably helping a lot.

Long-term results of prospective trial of surgery alone with selective use of radiation for patients with T1 extremity and trunk soft tissue sarcomas - PubMed

Selected patients with primary T1 STS of the extremity and trunk can be treated by R0 surgery alone with acceptable local control and excellent long-term survival.

pubmed.ncbi.nlm.nih.gov

 

[TheWallnerus]

Do you have a more specific histology than sarcoma?

There is no evidence to support treating drain sites. I don't have access to the protocol anymore but I think Sarc032 specifically says do not do it.

Don't bolus and use IMRT as it is now standard.

Also, you should just be aware of this prospective data that shows fairly low recurrence rates for small (<5 cm) superficial sarcomas that are resected with negative margins if you omit radiation. The decision is to omit is of course extremely personalized on a number of factors that aren't included in your description and histology matters a lot. If its a synovial sarcoma in a 25 year old you might not be helping by treating, if its a myxofibrosarcoma in a 60 year old you're probably helping a lot.

Long-term results of prospective trial of surgery alone with selective use of radiation for patients with T1 extremity and trunk soft tissue sarcomas - PubMed

Selected patients with primary T1 STS of the extremity and trunk can be treated by R0 surgery alone with acceptable local control and excellent long-term survival.

pubmed.ncbi.nlm.nih.gov

You’re like a sarcoma idiot savant!

 

[evilbooyaa]

I have a case of a pT1(4cm)N0MO Grade 2 sarcoma s/p resection by a good surg onc. Margins 4mm in two areas (deep and anterior), 1 mm "superficial" margin that surg onc feels is artifactually close (he took some skin). This was a superficial sarcoma in an obese leg. Just barely touched deep fascia but did not invade into muscle though surg onc took some muscle. Tumor involved saphenous vein and it had to be ligated.

Patient already has some minor distal edema.

I took a cartoon of a sarcoma from a paper and edited. My patients disease/operative bed goes no where close to deep bone so operative bed is in red. in my patient the red surgical bed is superficial. However, the drain is almost medial/midline. A nice little tangent plan will cover the operative bed well, but I'm concerned that if I treat the drain site it will increase lymphedema risk more. Do I have to cover this drain site? Is is worth it to maybe put an electron patch there? Or just forgo it the drain site.

Any thoughts are appreciated.
View attachment 361261

I know that this is not what you have asked. BUT - I have specifically recommended observation as noted above in a healthy patient with otherwise non-muscle invasive (say abutting fascia) who would be able to undergo a repeat resection if the superficial tumor was to recur, it would be identified quickly on physical exam, especially when < 5cm in size and with negative (no tumor on ink) margins.

If you are going to treat, I don't see a need to cover the drain site as the entire specimen is removed, then the drain is placed. If no positive margins, then no ability to seed the drain. Obviously not full-proof. I agree with no bolus if no skin involvement. I'd probably eval an oblique plan to see if it could be kept homogeneous enough with FiF, but based on the location I don't think IMRT is necessary for that case. Not wrong to do, I just don't know if there would be any advantage to it since you could completely spare bone and have excellent 'skin strip' with proposed 3D fields.

 

[BobbyHeenan]

Thanks all for the input.

Via private message some really smart docs that have forgotten more about sarcoma than I will ever know have reiterated consideration of observation as a viable option and if treating completely reasonable to not treat drain site.

Thanks!

I *thought* likely OK to avoid the drain site, but I needed some hand holding.

 

[evilbooyaa]

Thanks all for the input.

Via private message some really smart docs that have forgotten more about sarcoma than I will ever know have reiterated consideration of observation as a viable option and if treating completely reasonable to not treat drain site.

Thanks!

I *thought* likely OK to avoid the drain site, but I needed some hand holding.

I mean NMS and I said the same thing just publicly, but man, see how it is! Good thing NMS is actually not Matt Spraker, b/c that guy (Matt Spraker, not NMS) knows a ****-ton about sarcoma!

 

[NotMattSpraker]

I know that this is not what you have asked. BUT - I have specifically recommended observation as noted above in a healthy patient with otherwise non-muscle invasive (say abutting fascia) who would be able to undergo a repeat resection if the superficial tumor was to recur, it would be identified quickly on physical exam, especially when < 5cm in size and with negative (no tumor on ink) margins.

If you are going to treat, I don't see a need to cover the drain site as the entire specimen is removed, then the drain is placed. If no positive margins, then no ability to seed the drain. Obviously not full-proof. I agree with no bolus if no skin involvement. I'd probably eval an oblique plan to see if it could be kept homogeneous enough with FiF, but based on the location I don't think IMRT is necessary for that case. Not wrong to do, I just don't know if there would be any advantage to it since you could completely spare bone and have excellent 'skin strip' with proposed 3D fields.

I think IMRT should be a true standard. Good retrospective data shows a control advantage (Folkert data). I was once at CTOS and he couldn't explain it, but it was a high quality database and the study controlled for every covariate people could think of at the presentation.

As of last year, ASTRO published that in a guideline so insurances approve and Id be happy to share a letter template if it would be helpful. It could reasonably be added to NCCN especially given that there are drugs in there approved on tiny single arm studies measuring RR.

I try so hard to be open minded about everything but my experience the few times Ive had to treat with 3D have overwhelmingly biased me toward IMRT

I know that for lateralized tumors there are some sarcoma experts that value reducing low dose spread using "tangents". It's worth considering, but with the global risk benefit in this setting I just don't agree, even for young adults.

 

[Palex80]

I would not cover the drain site. I would use VMAT/IMRT.

 

[Radiator20]

Haven't posted in a while but surprised to find myself disagreeing with this thread.

First question is does it need to be treated at all. Agree with NMS's reference to the Pisters study re: potential for omission. Can run it through the MSK nomogram also, here / here. This is likely a salvageable location if not treated and recurrence later develops.

If it does need to be treated, use VMAT. VMAT > IMRT >> 3D for most extremity cases. IMRT/VMAT is better than 3D in terms of local control, acute dermatitis and wound healing complications, and late fracture risk. Best plan here is likely VMAT with skip arcs (yields falloff into uninvolved leg similar to 3D) and flash PTV. No bolus (almost never in STS).

I would likely treat the drain site. Reasons:

1. 2022 ASTRO consensus STS guidelines - flawed in some respects but nonetheless very helpful - "CTV1 includes the tumor bed with margin, the remainder of the operative field and scar, and the drain sites when feasible to cover areas at risk for potential tumor seeding at time of resection."

2. So is it "feasible" to treat the drain site in this case? Yes, absolutely, with VMAT. OP, I can't tell whether the tumor bed is medial or lateral on your diagram. If the tumor bed is medial, that's where your lymphedema risk is coming from. The lymphatic run predominantly in the medial thigh. So including a lateral drain site won't hurt. You'll still be far below circumferential dose constraints. If the tumor bed is lateral, then treating a medial drain site might indeed increase lymphedema risk.

3. If it failed in a drain site just outside of the current tumor bed radiation field, that would actually be a harder problem to salvage.

Evilbooya - " If no positive margins, then no ability to seed the drain" - respectfully disagree. Microscopic disease extends well beyond where positive margins would be called on pathology. Compare preop fields for any STS to the extent of a negative-margin resection -- preop fields are far larger. And yet, if you look, there are tumor cells way out there in the edema. That's why we treat there. And those cells can seed. Lower risk than with frank tumor cut-through, absolutely. But, as you say, not foolproof.

NMS - I respect your opinion a lot. But I see things differently here. I am not sure what you mean about SARC 032 not including drain sites - RT is preop on that study so there aren't any drain sites to cover. The standard for EBRT in sarcoma for decades has been to include drain sites, and as above that's reflected in current consensus guidelines. I agree this has not been well studied but with that background I would phrase it as - there's no evidence to support its omission.

So OP - I think either treat or don't, but if you do, be comprehensive.

 

[Palex80]

Haven't posted in a while but surprised to find myself disagreeing with this thread.

First question is does it need to be treated at all. Agree with NMS's reference to the Pisters study re: potential for omission. Can run it through the MSK nomogram also, here / here. This is likely a salvageable location if not treated and recurrence later develops.

If it does need to be treated, use VMAT. VMAT > IMRT >> 3D for most extremity cases. IMRT/VMAT is better than 3D in terms of local control, acute dermatitis and wound healing complications, and late fracture risk. Best plan here is likely VMAT with skip arcs (yields falloff into uninvolved leg similar to 3D) and flash PTV. No bolus (almost never in STS).

I would likely treat the drain site. Reasons:

1. 2022 ASTRO consensus STS guidelines - flawed in some respects but nonetheless very helpful - "CTV1 includes the tumor bed with margin, the remainder of the operative field and scar, and the drain sites when feasible to cover areas at risk for potential tumor seeding at time of resection."

I understand the ASTRO-statement, but wouldn't you have to treat the drain site + the "connection between the drain site and the CTV?

So. in this case


Which way did the drain go?
You would need to add a "connection" between drain site and surgical bed. Was it superficial? Was it deeper?

 

[BobbyHeenan]

Tumor was superficial. It abutted (?invaded? ) deep fascia and deep fascia and some muscle was taken at surgery to get wider margins. However vast majority of tumor was superficial.

The red is my attempt at a drawing. I suspect the drain tunneled all in the superficial fat. This patient isn’t morbidly obese (just regular obese) but has a generous amount of leg girth and seems to store fat in legs. This wasn’t self palpated until tumor was 3-4 cm, even though technically superficial.

I was trying to keep some details a little impersonal given the public forum.


We are more seriously considering observation but at immediate post op visit patient leaning radiation.

Thanks all for the input.

 

[Radiator20]

I understand the ASTRO-statement, but wouldn't you have to treat the drain site + the "connection between the drain site and the CTV?

So. in this case


Which way did the drain go?
You would need to add a "connection" between drain site and surgical bed. Was it superficial? Was it deeper?


View attachment 361504

Palex, you are exactly right - you would have to treat the drain tract connecting the skin drain site and the surgical bed. Very often this can be defined on postop MRI Gd+ or sim (40FOV and IV+) if you look hard enough. If not, then I just interpolate between drain site (+ ~1.5 cm) and what CTV1 otherwise would be. I think this is better imagined in the sagittal view - my own attempt below. I agree, for a superficial sarcoma I would assume the drain was tunneled through the superficial compartment.

 

[elementaryschooleconomics]

 

[TheWallnerus]

Palex, you are exactly right - you would have to treat the drain tract connecting the skin drain site and the surgical bed. Very often this can be defined on postop MRI Gd+ or sim (40FOV and IV+) if you look hard enough. If not, then I just interpolate between drain site (+ ~1.5 cm) and what CTV1 otherwise would be. I think this is better imagined in the sagittal view - my own attempt below. I agree, for a superficial sarcoma I would assume the drain was tunneled through the superficial compartment.

View attachment 361519

*not to scale

 

[NotMattSpraker]

Evilbooya - " If no positive margins, then no ability to seed the drain" - respectfully disagree. Microscopic disease extends well beyond where positive margins would be called on pathology. Compare preop fields for any STS to the extent of a negative-margin resection -- preop fields are far larger. And yet, if you look, there are tumor cells way out there in the edema. That's why we treat there. And those cells can seed. Lower risk than with frank tumor cut-through, absolutely. But, as you say, not foolproof.

NMS - I respect your opinion a lot. But I see things differently here. I am not sure what you mean about SARC 032 not including drain sites - RT is preop on that study so there aren't any drain sites to cover. The standard for EBRT in sarcoma for decades has been to include drain sites, and as above that's reflected in current consensus guidelines. I agree this has not been well studied but with that background I would phrase it as - there's no evidence to support its omission.

So OP - I think either treat or don't, but if you do, be comprehensive.

I think the comment was for if a post-op boost is needed? I don't have the protocol anymore so I can't check if i am right on that.

This is an interesting take, I like it. I went back to read the section on drain sites and bolus in the full guideline (they are discussed together). The main take home point is that the outcomes are affected by the surgical setting. An extreme example is like if you have a novice surgeon that doesnt remove the overlaying skin with biopsy tract or puts a drain through tumor, yes you should cover it and maybe even use bolus.

They use this line of thinking to explain why you should not use bolus in most cases. They never expand on the point for drains, but I think you should also not cover drains for the same reasons.

This idea is supported by the Gundle paper that looked at this issue for margin status Analysis of Margin Classification Systems for Assessing the Risk of Local Recurrence After Soft Tissue Sarcoma Resection - PubMed.

This would make a great QI study, I do wish there was more evidence about this question of drain coverage and also bolus. They did it in mesothelioma, it can be done in sarcoma!

 

[evilbooyaa]

Haven't posted in a while but surprised to find myself disagreeing with this thread.

That's the best part of SDN, where you get to come in hot and disagree with people, and it doesn't matter who you are or who you disagree with, even if it's the mod!

I don't disagree with anything you've said. Not to say that I would treat exactly as you have outlined, but that you have made an excellent point that I will consider if/when I am ever in this clinical situation for my own patient.