treating IM nodes

[BraggPeak]

Could someone please explain different treatment techniques for treating IM Nodes (how you do the match in the 5-field, how you define (in terms of borders) deep vs shallow tangents)

Also, do you ever do a 5-field plan with ABC?

Thanks!

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[TarHeelRadOnc]

Could someone please explain different treatment techniques for treating IM Nodes (how you do the match in the 5-field, how you define (in terms of borders) deep vs shallow tangents)

Also, do you ever do a 5-field plan with ABC?

Thanks!

Couple good sources out there. Article below compares conventional (non-IMRT) techniques. NCIC MA.20 protocol a good source for IMN techniques in the breast conservation setting. I am not a big believer in gating or deep inspiratory breath hold (ABC) for breast either way. Greatest benefit of these techniques, IMO, is in the setting of external beam APBI.... would not use for 5 field.

Internal mammary node coverage: an investigation of presently accepted techniques.
Arthur DW, Arnfield MR, Warwicke LA, Morris MM, Zwicker RD.
Int J Radiat Oncol Biol Phys. 2000 Aug 1;48(1):139-46.

 

[Brim]

Postmastectomy radiotherapy of the chest wall: dosimetric comparison of common techniques.
Pierce LJ, Butler JB, Martel MK, Normolle DP, Koelling T, Marsh RB, Lichter AS, Fraass BA.
Int J Radiat Oncol Biol Phys. 2002 Apr 1;52(5):1220-30.

 

[BraggPeak]

Thanks, those were really helpful!
Are deep and partially wide tangents the same thing?

How about high tangents?

 

[Brim]

Thanks, those were really helpful!
Are deep and partially wide tangents the same thing?

How about high tangents?

Those 3 are all different.

Deep tangents are relatively simple. They treat the IMNs and chest wall in a pair of deep tangent fields. There's probably no good reason to use this technique in the era of modern 3D planning, since it includes a lot of heart + lung in the fields.

Partially wide tangents are wide (deep) superiorly to include the IMNs but become narrow below the IMNs, shielding more heart + lung -- thus "partially wide".

See "To treat or not to treat the internal mammary nodes: a possible compromise."
Marks LB
Int J Radiat Oncol Biol Phys. 1994 Jul 1;29(4):903-9.​

Deep tangents have nothing to do with either of these. In high tangents, the superior tangent border is placed high -- 2 cm from the bottom of the humeral head -- in order to treat the axilla in the tangents. You might use this technique in someone who hasn't undergone a SLN biopsy.

see "Relationship of sentinel and axillary level I-II lymph nodes to tangential fields used in breast irradiation."
Schlembach PJ
Int J Radiat Oncol Biol Phys. 2001 Nov 1;51(3):671-8.​

 

[deleted4401]

Thanks for those. Good review of techniques.
Is anyone treating these any more if not clinically positive? Did that trial that was presented at ASTRO answer any questions? I just don't really ever treat them.
S

 

[Palex80]

Thanks for those. Good review of techniques.
Is anyone treating these any more if not clinically positive? Did that trial that was presented at ASTRO answer any questions? I just don't really ever treat them.

We sometimes treat IM nodes even if they are not clinically positive.
We only do this probably like once every couple of months.
Those are usually patients with something like 23/23 positive axillary nodes, with a pT3 primary and generally of younger age.
We use IMRT for it.

The ASTRO trial was powered to detect an overall survival difference of 10% over standard chest wall irradiation, if I correctly remember. Such an expected survival benefit through adding IM-RT is clearly illusional. Therefore the trial was not designed to answer the interesting question, which would have been if IM-RT could lower isolated nodal failure in IM chain.

 

[TarHeelRadOnc]

We sometimes treat IM nodes even if they are not clinically positive.
We only do this probably like once every couple of months.
Those are usually patients with something like 23/23 positive axillary nodes, with a pT3 primary and generally of younger age.
We use IMRT for it.

The ASTRO trial was powered to detect an overall survival difference of 10% over standard chest wall irradiation, if I correctly remember. Such an expected survival benefit through adding IM-RT is clearly illusional. Therefore the trial was not designed to answer the interesting question, which would have been if IM-RT could lower isolated nodal failure in IM chain.

I treat for patients with inflammatory breast ca and post-mastectomy with pN3 disease or medial primary with pN2 disease. Recent chinese study of patients undergoing extended RM showed high rate of pathologically positive IMNs in patients with medial/central primary and 4+ nodes positive and in patients with primary at any site with 10+ nodes positive. French study from ASTRO excluded patients with stage III disease, so relevant data even more scarce in this population. For intact breast, I generally avoid treating IMNs.... MA.20 may change my approach, if ever reported...

 

[Palex80]

I treat for patients with inflammatory breast ca and post-mastectomy with pN3 disease or medial primary with pN2 disease. Recent chinese study of patients undergoing extended RM showed high rate of pathologically positive IMNs in patients with medial/central primary and 4+ nodes positive and in patients with primary at any site with 10+ nodes positive. French study from ASTRO excluded patients with stage III disease, so relevant data even more scarce in this population. For intact breast, I generally avoid treating IMNs.... MA.20 may change my approach, if ever reported...

Do you have a link for that Chinese study, sounds interesting!

 

[TarHeelRadOnc]

Do you have a link for that Chinese study, sounds interesting!

Breast cancer subpopulation with high risk of internal mammary lymph nodes metastasis: analysis of 2,269 Chinese breast cancer patients treated with extended radical mastectomy.
Huang O, Wang L, Shen K, Lin H, Hu Z, Liu G, Wu J, Lu J, Shao Z, Han Q, Shen Z.
Breast Cancer Res Treat. 2008 Feb;107(3):379-87. Epub 2007 Apr 25.PMID: 17457670 [PubMed - indexed for MEDLINE]

 

[Palex80]

Great reading, thank a lot!

 

[Radonc90]

Thanks for those. Good review of techniques.
Is anyone treating these any more if not clinically positive? Did that trial that was presented at ASTRO answer any questions? I just don't really ever treat them.
S

1+,

I don't treat IM nodes any more, it is more or less of historical interest.
To answer the 1st post, many years ago, we used the "hockey-stick" approach.

 

[IonsAreOurFuture]

This is an old thread, but newer technology advances, like pencil beam protons, make it relevant again.

For treating IM nodes, I find that wide tangents often take a big bite out of lung and heart, and even with IMRT I often have had a hard time meeting the NSABP B-51 constraint for 4 Gy mean heart dose.

Exit into the contralateral breast is often an issue too, especially if the patient is large breasted or has expanders post mastectomy. 5 fields with supraclav, PAB, tangents and matched electrons can be a therapist's challenge for field junctions, and usually has a cold triangle or hot match line at the anterior chest wall.

Protons on the other hand, have none of those issues, but you can have higher rates of skin reactions and rib fractures if you don't pay careful attention to superficial and deep doses, particularly with passive- scattering older systems which give hotter skin doses and can't be tailored to depth as well as pencil beam now does.

 

[jondunn]

This is an old thread, but newer technology advances, like pencil beam protons, make it relevant again.

For treating IM nodes, I find that wide tangents often take a big bite out of lung and heart, and even with IMRT I often have had a hard time meeting the NSABP B-51 constraint for 4 Gy mean heart dose.

Exit into the contralateral breast is often an issue too, especially if the patient is large breasted or has expanders post mastectomy. 5 fields with supraclav, PAB, tangents and matched electrons can be a therapist's challenge for field junctions, and usually has a cold triangle or hot match line at the anterior chest wall.

Protons on the other hand, have none of those issues, but you can have higher rates of skin reactions and rib fractures if you don't pay careful attention to superficial and deep doses, particularly with passive- scattering older systems which give hotter skin doses and can't be tailored to depth as well as pencil beam now does.

what's the cash back bonus you got going on

 

[elementaryschooleconomics]

This is an old thread, but newer technology advances, like pencil beam protons, make it relevant again.

For treating IM nodes, I find that wide tangents often take a big bite out of lung and heart, and even with IMRT I often have had a hard time meeting the NSABP B-51 constraint for 4 Gy mean heart dose.

Exit into the contralateral breast is often an issue too, especially if the patient is large breasted or has expanders post mastectomy. 5 fields with supraclav, PAB, tangents and matched electrons can be a therapist's challenge for field junctions, and usually has a cold triangle or hot match line at the anterior chest wall.

Protons on the other hand, have none of those issues, but you can have higher rates of skin reactions and rib fractures if you don't pay careful attention to superficial and deep doses, particularly with passive- scattering older systems which give hotter skin doses and can't be tailored to depth as well as pencil beam now does.

Did you just necropost for proton breast hype????

What's your preferred palliative scheme for an uncomplicated bone met? 40 Gy in 20 fractions, pencil beam?

 

[Burt Radnolds]

Exit into the contralateral breast is often an issue too, especially if the patient is large breasted or has expanders post mastectomy.

If a patient has expanders post mastectomy, I typically find the contralateral breast to no longer be of concern.

 

[Mandelin Rain]

I’m just a simple community radiation oncologist, but the IMNs almost exclusively live in the first second and third intercostal spaces. On a breast board, with arms up, and breath hold, I can pretty easily meet any cardiac constraint with simple partially wide targets that barely cross midline (~1 cm). If not, IMRT does amazing. The left ventricle is what comes close to typical tangent fields, but that’s down around interspace 4-5 by the time it’s approaching the chest wall absent some aberrant anatomy.

I guess I just see a lot less high riding, incredibly anterior hearts than the proton centers who are out here melting skin and breaking ribs in the name of “less toxicity”.

 

[RSAOaky]

A big reason this field is heading in the direction it is is that while we spend our energy arguing with one another about the optimal way to treat a set of nodes that it's questionable if we need to treat to begin with, everyone else is trying to figure out how we can omit radiation completely.

 

[elementaryschooleconomics]

A big reason this field is heading in the direction it is is that while we spend our energy arguing with one another about the optimal way to treat a set of nodes that it's questionable if we need to treat to begin with, everyone else is trying to figure out how we can omit radiation completely.

Completely agree.

One of the breast surgeons this week expressed concerns about a particular patient's anatomy and if we were going to be able to irradiate a particular spot. She was under the reasonable delusion that we were very precise with our breast radiation like we are for say, SRS. I discussed how, despite significant advancements in our technology, we're basically "not allowed" to do anything but big rectangles for breast, so no, I was not worried about "missing" on this particular patient.

How about, before we jump right to protons for breast - we avail ourselves of the photon techniques we use for literally all other disease sites?

 

[deleted1116990]

I still have yet to hear a non-insane explanation of why 50 Gy is needed to kill microscopic breast carcinoma, unless it's in the IMNs, in which case 40 Gy will conveniently do. Other than straight up magic.

I’m just a simple community radiation oncologist, but the IMNs almost exclusively live in the first second and third intercostal spaces. On a breast board, with arms up, and breath hold, I can pretty easily meet any cardiac constraint with simple partially wide targets that barely cross midline (~1 cm). If not, IMRT does amazing. The left ventricle is what comes close to typical tangent fields, but that’s down around interspace 4-5 by the time it’s approaching the chest wall absent some aberrant anatomy.

I guess I just see a lot less high riding, incredibly anterior hearts than the proton centers who are out here melting skin and breaking ribs in the name of “less toxicity”.

I just saw a patient who got proton 60 GyE in 20 fractions for a sternal bone met (breast). The late toxicity was impressive. And the tumor kept growing anyway.

 

[elementaryschooleconomics]

I still have yet to hear a non-insane explanation of why 50 Gy is needed to kill microscopic breast carcinoma, unless it's in the IMNs, in which case 40 Gy will conveniently do. Other than straight up magic.

I also am constantly seeking consistency in what our specialty considers gospel.

If anyone ever finds it, DM me.

 

[Mandelin Rain]

I just saw a patient who got proton 60 GyE in 20 fractions for a sternal bone met (breast). The late toxicity was impressive. And the tumor kept growing anyway.

Choosing wisely.

 

[evilbooyaa]

This is an old thread, but newer technology advances, like pencil beam protons, make it relevant again.

For treating IM nodes, I find that wide tangents often take a big bite out of lung and heart, and even with IMRT I often have had a hard time meeting the NSABP B-51 constraint for 4 Gy mean heart dose.

Exit into the contralateral breast is often an issue too, especially if the patient is large breasted or has expanders post mastectomy. 5 fields with supraclav, PAB, tangents and matched electrons can be a therapist's challenge for field junctions, and usually has a cold triangle or hot match line at the anterior chest wall.

Protons on the other hand, have none of those issues, but you can have higher rates of skin reactions and rib fractures if you don't pay careful attention to superficial and deep doses, particularly with passive- scattering older systems which give hotter skin doses and can't be tailored to depth as well as pencil beam now does.

A 12 year necrobump?

Why do all proton folks have no semblance of where standard borders for IM nodes are? Sure, you want to treat the rare patient with clinically IM positive and chase the entire chain inferiorly where it's actually co-planar with the heart... sure. But first 3 intercostal spaces are 99% of the time above the heart musculature. Many dosimetrists just contour heart all the way up to great vessels, which is silly.

Static field IMRT if 3D can't make it happen. I used to be a poo-pooer of IMRT for breast, now I'm a believer in select cases where 3D doesn't do it. I'm still not a fan of VMAT though.

I’m just a simple community radiation oncologist, but the IMNs almost exclusively live in the first second and third intercostal spaces. On a breast board, with arms up, and breath hold, I can pretty easily meet any cardiac constraint with simple partially wide targets that barely cross midline (~1 cm). If not, IMRT does amazing. The left ventricle is what comes close to typical tangent fields, but that’s down around interspace 4-5 by the time it’s approaching the chest wall absent some aberrant anatomy.

I guess I just see a lot less high riding, incredibly anterior hearts than the proton centers who are out here melting skin and breaking ribs in the name of “less toxicity”.

Agreed.

 

[deleted1111261]

I was also Poo Poo-ing IMRT/VMAT, but sometimes it is just better. Barrel chested women with a very curved lung contour where the tangent would take huge bite of lung.

Why static > VMAT? I think both look good.

 

[elementaryschooleconomics]

I was also Poo Poo-ing IMRT/VMAT, but sometimes it is just better. Barrel chested women with a very curved lung contour where the tangent would take huge bite of lung.

Why static > VMAT? I think both look good.

Yeah I'm curious too, I've done both and like both.

@evilbooyaa always has a rationale, and I'm here for the learning.

 

[evilbooyaa]

I still have yet to hear a non-insane explanation of why 50 Gy is needed to kill microscopic breast carcinoma, unless it's in the IMNs, in which case 40 Gy will conveniently do. Other than straight up magic.


I just saw a patient who got proton 60 GyE in 20 fractions for a sternal bone met (breast). The late toxicity was impressive. And the tumor kept growing anyway.

1st part - You don't need 50Gy. 90-95% of that at the posterior edge of the LN volumes is sufficient. Some say you don't even need 40Gy for the IMNs, you can get by just fine with 0Gy.

2nd part - Interesting dosing. I mean glad someone else did it though, can you imagine if you gave 30/10 and it failed, how much **** talking there would be?! Now the patient can have tumor recurrence and late toxicity.

I was also Poo Poo-ing IMRT/VMAT, but sometimes it is just better. Barrel chested women with a very curved lung contour where the tangent would take huge bite of lung.

Why static > VMAT? I think both look good.

To me this probably comes down to your dosimetrist's abilities more than anything else - IMRT > VMAT in this scenario is only my preference - it's simply what I've seen with VMAT vs static IMRT.
I find that a dosimetrist can be good at picking beam angles that obviously don't enter through the heart for static IMRT, but also strongly minimize exit dose into the heart but allow sufficient coverage of the other fields.

The occasional RNI plans I have seen for VMAT all seemed to have the same problem - MHD was too high because of how the dose was splayed, and the V20 IDL bowed into the lung rather than towards the chest wall. Now, I was not planning them myself, so perhaps there is some special way to plan VMAT that doesn't lead to those issues. But when the same dosi on the same patient shows me a beautiful static field IMRT plan, do I believe my eyes, or force the planner to continue VMAT and push, push, push on heart and lung? Yes, the patient is on the table a bit longer than a VMAT plan, but I haven't personally seen a VMAT plan be equal to static IMRT. Doesn't mean there isn't somebody out there putting it together.

But, if you're accepting MHD > 2-3 on a right chest wall/RNI plan or MHD > 4-5 on a left chest wall/RNI plan because of VMAT, see what static beam IMRT can get you.

The other relevant concern is that we flash the skin in breast cancer. Flashing skin with static field IMRT seems to be relatively simple. Flashing the skin with VMAT (like is done in say Vulvar cancer) is a whole process that still throws planners for a loop.

 

[taserlaser]

We use a **** tonne of 3D field in field for our breast plans. I’ve been asked at my group at coming up with more robust VMAT planning workflows, and i will agree it’s challenging to come up with something robust that has flash, and doesn’t also just spray dose everywhere. Considering that we will use it when there is something wonky for why are doing VMAT anyways, it often ends up being something one-off that is probably sub optimal. Any tips people have are welcome - I’ve done as much reading as I can and have seen people describe 6x partial arcs to other craziness but nothing yet seems to ‘stick’ I find that consistently works well. Probably just need more cases and institutional experience I think since we don’t do it often at all.

For the partial breast setups at the two places I’ve worked at, one has done VMAT, and the other uses 5-field non-coplanar IMRT. VMAT was great for ease of planning and throughput but I think the static fields results in better sparing of wash to heart/lungs/etc. But is this necessary in the era of mini tangents and 5-fraction whole breast? Who knows.

 

[seper]

We use a **** tonne of 3D field in field for our breast plans. I’ve been asked at my group at coming up with more robust VMAT planning workflows, and i will agree it’s challenging to come up with something robust that has flash, and doesn’t also just spray dose everywhere. Considering that we will use it when there is something wonky for why are doing VMAT anyways, it often ends up being something one-off that is probably sub optimal. Any tips people have are welcome - I’ve done as much reading as I can and have seen people describe 6x partial arcs to other craziness but nothing yet seems to ‘stick’ I find that consistently works well. Probably just need more cases and institutional experience I think since we don’t do it often at all.

For the partial breast setups at the two places I’ve worked at, one has done VMAT, and the other uses 5-field non-coplanar IMRT. VMAT was great for ease of planning and throughput but I think the static fields results in better sparing of wash to heart/lungs/etc. But is this necessary in the era of mini tangents and 5-fraction whole breast? Who knows.

breast IMRT often looks great on the screen, but immobilization is a problem

 

[Burt Radnolds]

Used to feel the same way about vmat and undesirable dose to lungs/heart but I've found that with partial arcs, appropriate optimization and reasonable coverage goals you can get some stunning vmat plans. Still prefer 3d majority of the time. I can get lost tweaking the crap out of a RNI 3D plan to perfection. Also multiple TPS have an auto flash VMAT setting that you can turn on which flashes the segments tangential to the surface even if you've cropped ptv inside. I've clicked through the arcs segment by segment to confirm that it indeed is doing what it's supposed to and can confirm that at least for our implementation, it works.

 

[madchemist89]

What coverage goals are you using? Do you dose paint to mimic the coverage of a traditional 3d plan?

 

[taserlaser]

I personally wouldn’t mind relaxing coverage in a lot of these circumstances as I suspect it helps like you said, but might throw these planners for a loop, especially for Pushing over multiple optimizations. As above with what is the ‘right‘ dose to cover IMNs at, who knows, and that also adds ‘complexity’.

How our dept is structured it seems that most of the breast workhorses tend to be more adept for 3D planning wizardry and the complex VMAT planners are shuffled more to the H&N/CNS/abdo pelvis plan side. Which is fine when the bulk of the work is FnF but then situations like these arise where it’s almost like forcing a square peg round hole. So to answer the chemist’s question, unless another RO told them specifically otherwise, I think they’re trying to ask the TPS for 95/95

 

[Palex80]

We did not use 3D for a single breast case in the past year and we treat a few hundred breast cases per year.
It's all VMAT now. Whole breast, Partial breast, resection cavity boost, chest wall, with/without RNI.
I fear our dosimetrists will not be able to calculate a 3D plan in a few years...


Ok, fry me now...

 

[madchemist89]

The reason I ask about dose painting is that if you try to achieve 95/95 and you are treating the whole breast or chest wall and nodes then your coverage is great but lung and heart doses are higher. We require really good coverage for vmat plans, but we accept much worse dosimetry for 3d. I believe vmat has potential to be better but we have to apply 3d standards to planning or else oars can be worse.

 

[BobbyHeenan]

I was also Poo Poo-ing IMRT/VMAT, but sometimes it is just better. Barrel chested women with a very curved lung contour where the tangent would take huge bite of lung.

Why static > VMAT? I think both look good.

I did very little IMRT/VMAT in residency but I've done more and more now (yes, depends a lot on patient anatomy). I enrolled a few patients on B51 and those constraints can be hard to meet . As I recall, I actually ended up using IMRT on a couple of them where I couldn't with 3D.

Aside - I wonder how many on B51 didn't have constraints met the same way that I've heard on 0529 (anal) no one really met all those constraints.

 

[medgator]

We did not use 3D for a single breast case in the past year and we treat a few hundred breast cases per year.
It's all VMAT now. Whole breast, Partial breast, resection cavity boost, chest wall, with/without RNI.
I fear our dosimetrists will not be able to calculate a 3D plan in a few years...


Ok, fry me now...

People with tomo or halcyon only practices have been doing it for awhile I'm sure

 

[deleted1116990]

1st part - You don't need 50Gy. 90-95% of that at the posterior edge of the LN volumes is sufficient. Some say you don't even need 40Gy for the IMNs, you can get by just fine with 0Gy.

My comment was about the B51 constraints allowing for 90@90 for breast and nodes except for IMNs where 90@80 is ok. I would love to know the scientific rationale for allowing this dose reduction in this location only. If we're going to treat something, then we should treat it to the minimum dose needed for complete cell kill. If we don't know what that is, then we shouldn't be asking that question in a trial designed to answer a different question. The variability of IMN dosing across different trials is less than satisfying and makes it difficult to understand if they need to be treated at all.

 

[evilbooyaa]

We did not use 3D for a single breast case in the past year and we treat a few hundred breast cases per year.
It's all VMAT now. Whole breast, Partial breast, resection cavity boost, chest wall, with/without RNI.
I fear our dosimetrists will not be able to calculate a 3D plan in a few years...


Ok, fry me now...

Beauty of being a EU RO, get to do whatever you want!

My comment was about the B51 constraints allowing for 90@90 for breast and nodes except for IMNs where 90@80 is ok. I would love to know the scientific rationale for allowing this dose reduction in this location only. If we're going to treat something, then we should treat it to the minimum dose needed for complete cell kill. If we don't know what that is, then we shouldn't be asking that question in a trial designed to answer a different question. The variability of IMN dosing across different trials is less than satisfying and makes it difficult to understand if they need to be treated at all.

Fair points - I usually shoot for 90/90 on my CTV for IMNs (shoot for 95/95 for breast CTV cropped from skin) though even with 3D planning. To me all of breast can be planned on CTV alone in terms of evaluating coverage without issues, given that patients were treated on 2D and did fine. While we created PTVs for patient's enrolled on B51, that is not my practice for any breast patient receiving 3D treatment.

 

[deleted1111261]

1st part - You don't need 50Gy. 90-95% of that at the posterior edge of the LN volumes is sufficient. Some say you don't even need 40Gy for the IMNs, you can get by just fine with 0Gy.

2nd part - Interesting dosing. I mean glad someone else did it though, can you imagine if you gave 30/10 and it failed, how much **** talking there would be?! Now the patient can have tumor recurrence and late toxicity.



To me this probably comes down to your dosimetrist's abilities more than anything else - IMRT > VMAT in this scenario is only my preference - it's simply what I've seen with VMAT vs static IMRT.
I find that a dosimetrist can be good at picking beam angles that obviously don't enter through the heart for static IMRT, but also strongly minimize exit dose into the heart but allow sufficient coverage of the other fields.

The occasional RNI plans I have seen for VMAT all seemed to have the same problem - MHD was too high because of how the dose was splayed, and the V20 IDL bowed into the lung rather than towards the chest wall. Now, I was not planning them myself, so perhaps there is some special way to plan VMAT that doesn't lead to those issues. But when the same dosi on the same patient shows me a beautiful static field IMRT plan, do I believe my eyes, or force the planner to continue VMAT and push, push, push on heart and lung? Yes, the patient is on the table a bit longer than a VMAT plan, but I haven't personally seen a VMAT plan be equal to static IMRT. Doesn't mean there isn't somebody out there putting it together.

But, if you're accepting MHD > 2-3 on a right chest wall/RNI plan or MHD > 4-5 on a left chest wall/RNI plan because of VMAT, see what static beam IMRT can get you.

The other relevant concern is that we flash the skin in breast cancer. Flashing skin with static field IMRT seems to be relatively simple. Flashing the skin with VMAT (like is done in say Vulvar cancer) is a whole process that still throws planners for a loop.

I will try it- just told dosimetrist to give it a whirl.

We did not use 3D for a single breast case in the past year and we treat a few hundred breast cases per year.

It's all VMAT now. Whole breast, Partial breast, resection cavity boost, chest wall, with/without RNI.
I fear our dosimetrists will not be able to calculate a 3D plan in a few years...


Ok, fry me now...

no frying. What do you use for whole breast constraints?

Michigan study showing better outcomes statewide in their consortium with IMRT. They were not expecting that.

 

[Palex80]

What do you use for whole breast constraints?

Ipsilateral lung
V20 ≤15%
V10 ≤35%
V5 ≤50%

Contralateral lung
V5 ≤10%

Heart (left sided primary)
mean dose ≤ 4 Gy
V20 ≤5%
V10 ≤30%

These are all contraints without DIBH.

We are generally very strict concerning target coverage.

 

[deleted1111261]

Ipsilateral lung
V20 ≤15%
V10 ≤35%
V5 ≤50%

Contralateral lung
V5 ≤10%

Heart (left sided primary)
mean dose ≤ 4 Gy
V20 ≤5%
V10 ≤30%

These are all contraints without DIBH.

We are generally very strict concerning target coverage.

4 Gy?!?
V20<15

Have you tried prone breast with tangents ? It will blow your mind

 

[Palex80]

4 Gy?!?
V20<15

Have you tried prone breast with tangents ? It will blow your mind

Yes, we (and the patients too) hated it. The equipment is full of dust in the corner of our storage room.

I am aware that many in the US love prone breast, in Europe it's less common, in my experience.

 

[jondunn]

a mean of 4 Gy? really?

 

[Palex80]

a mean of 4 Gy? really?

Yes.
Here are the heart constraints from a currently running randomized European trial with a few thousand patients.

V17 and V35 in brackets are for hypofractionated schedules.

 

[elementaryschooleconomics]

Yes.
Here are the heart constraints from a currently running randomized European trial with a few thousand patients.
View attachment 348690


V17 and V35 in brackets are for hypofractionated schedules.

Ah, this ruffles the feathers of the Americans.

I think most of us have a heart mean less than 4Gy for left-sided breast drilled into our soul as the hard limit, and there are (potentially apocryphal) stories of people failing boards for accepting 4-6Gy for a breast case (@evilbooyaa was the most recent to have a story like that, I think). Technically, I think B51 allows up to 5Gy for mean heart?

Personally, I ask my planners to aim for 2Gy or less, which is obviously very difficult in RNI cases (shoot for the moon, because if you miss, you'll still land among the stars and all that). I have drank the Kool-Aid that protecting the heart is second only in priority to PTV coverage, but it's hard to argue with an entire continent.

 

[BobbyHeenan]

Ah, this ruffles the feathers of the Americans.

I think most of us have a heart mean less than 4Gy for left-sided breast drilled into our soul as the hard limit, and there are (potentially apocryphal) stories of people failing boards for accepting 4-6Gy for a breast case (@evilbooyaa was the most recent to have a story like that, I think). Technically, I think B51 allows up to 5Gy for mean heart?

Personally, I ask my planners to aim for 2Gy or less, which is obviously very difficult in RNI cases (shoot for the moon, because if you miss, you'll still land among the stars and all that). I have drank the Kool-Aid that protecting the heart is second only in priority to PTV coverage, but it's hard to argue with an entire continent.

If you look at the supplement of the Darby paper (that supplement is the best part of the paper)...the absolute difference in cardiac events is not much between 2-5 Gy.

 

[elementaryschooleconomics]

If you look at the supplement of the Darby paper (that supplement is the best part of the paper)...the absolute difference in cardiac events is not much between 2-5 Gy.

View attachment 348694

View attachment 348693

Oh yes definitely, but you're talking about that pesky "reality".

I think about medicine as "reality" and "perceived reality". Reality is, of course, virtually unknowable.

Perceived reality is that "there's a 7.4% increase in cardiac events for each 1Gy mean heart dose".

And if I find myself in a courtroom with a lawyer asking me what mean heart dose I accepted in a patient with an adverse outcome, you bet your butt I won't be pontificating about absolute values in a supplement to a manuscript.

Does it make my skin tingle? Sure. The one thing SDN has taught me is that I wish I was in Europe.

 

[Palex80]

The one thing SDN has taught me is that I wish I was in Europe.

Unfortunately, we just hired a new resident.

 

[deleted1111261]

4 gy for right sided is hard to accept!

I meant your whole breast constraints for IMRT if not treating nodes. Has to be tighter than what you mentioned?

 

[Palex80]

4 gy for right sided is hard to accept!

I meant your whole breast constraints for IMRT if not treating nodes. Has to be tighter than what you mentioned?

Heart constraints only appy to left side. We do not distinguish between nodes or not when it comes to constraints, or let’s say we don’t have two sets of constraints with/without RNI. The table I showed is actually from a randomized trial looking at WBRT +/- RNI, there’s only one set of constraints there.

But yes, heart doses are lower when not treating nodes. Do I block out the heart to push my mean dose <2.5 Gy? No.

 

[evilbooyaa]

Yes.
Here are the heart constraints from a currently running randomized European trial with a few thousand patients.
View attachment 348690


V17 and V35 in brackets are for hypofractionated schedules.

Yes and B51 also had that (MHD < 4Gy) as a per protocol I believe, but big national trials are basically to be as inclusive as possible, including people of various skill levels, judgment thresholds, technological capabilities, etc.

I think if a dosimetrist showed me a MHD of 3.9Gy on a left side tangents alone in the absence of say cavity directly overlying the heart... I'd have a problem.

Doubly so if the dosimetrist wanted me to treat it with VMAT rather than 3D and was having VMAT spray dose into the heart to increase MHD.

I suppose... YMMV.