Skin case of right antihelix

[FrostyHammer]

I don't see many skin cases so I thought I'd get everyone's input on it...

89 y.o. gentleman with a 2.4 cm SCC in his right superior antihelix (near the crura), derm debulked/shaved off most of it.

My questions are pretty basic since I don't do many of these cases: 1) head setup/immobilization? 2) bolus needed and if so the type/placement? 3) any other considerations worth knowing?

Thanks in advance!
FH

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[mheat3]

I don't see many skin cases so I thought I'd get everyone's input on it...

89 y.o. gentleman with a 2.4 cm SCC in his right superior antihelix (near the crura), derm debulked/shaved off most of it.

My questions are pretty basic since I don't do many of these cases: 1) head setup/immobilization? 2) bolus needed and if so the type/placement? 3) any other considerations worth knowing?

Thanks in advance!
FH

I like to get diagnostic imaging if possible (MRI neck or CT) for adenopathy assessment including parotids. I treat mine with long mask and bolus made flush underneath mask (0.5 cm usually). If aggressive histology (i.e. poorly differentiated, extensive LVSI, PNI, recurrent disease) I do consider treating the nodes (parotids + upper neck ipsi) and having a discussion with patient regarding pros/cons (i.e. dry mouth much more likely with nodes).

 

[evilbooyaa]

I do not believe in ENI for really any skin cancer that has not demonstrated that it is already aggressive enough to go to a node (like the numerous SCC to parotid patients I get). I would be happy to review any data that suggests benefit of ENI in cutaneous SCC.

MRI r/o PNI in the setting of aggressive features on biposy not unreasonable. OK to consider CT r/o adenopathy as well. In an 89yo, especially if this was present for a long-time, I think likelihood is low.

I think mask is fine, but also would consider taping head to avoid mas as you really just need to be accurate with your en face electrons. Would try for 0.5cm bolus although may have to use something more conforming than superflab for the area. TLD day 1 to confirm dose is where you need it to be.

 

[FrostyHammer]

I'm sorry for the lack of info - it was moderately differentiated. They did a shave type of debulking so they can't assess LVI/PNI as far as I can tell, but I'm no pathologist.

So for the guys who answered (and to anyone else reading this), how would you make sure the bolus stays flush with the area? I doubt superflab can stay flush like that...any other ideas? Laying lateral decubitus helps with the bolus, but even then it may not be conformal to the area and I'm not sure how reproducible it is.

Any thoughts are of course appreciated...

 

[medgator]

I'm sorry for the lack of info - it was moderately differentiated. They did a shave type of debulking so they can't assess LVI/PNI as far as I can tell, but I'm no pathologist.

So for the guys who answered (and to anyone else reading this), how would you make sure the bolus stays flush with the area? I doubt superflab can stay flush like that...any other ideas? Laying lateral decubitus helps with the bolus, but even then it may not be conformal to the area and I'm not sure how reproducible it is.

Any thoughts are of course appreciated...

We have a pink bolus material that conforms to the cavity, almost like gack/slime lol. I'll try to find out the name of it tomorrow.

 

[RadOncDoc21]

We have a pink bolus material that conforms to the cavity, almost like gack/slime lol. I'll try to find out the name of it tomorrow.

Is it the same stuff found inside chicken McNuggets?

 

[thecarbonionangle]

Use that moldable bolus, idk name but has like a playdo like texture or you can use warm beeswax and make a bolus. Would fractionate a bit more rather than trying 10ish fx regimen

 

[FrostyHammer]

We have like no resources when it comes to that stuff. I think all we have is superflab or wet gauze and I think neither is particularly good...any ideas?

 

[medgator]

Use that moldable bolus, idk name but has like a playdo like texture or you can use warm beeswax and make a bolus. Would fractionate a bit more rather than trying 10ish fx regimen

I do 20-22 fx to the ear/nose/pretibial regions, no less. Shame away!

 

[thecarbonionangle]

You can get bees wax very cheap at any store (hobby lobby). It has a melting point in 60s celcius. You pour it over area, it cools and you can cut off areas as you like

 

[Palex80]

You can get bees wax very cheap at any store (hobby lobby). It has a melting point in 60s celcius. You pour it over area, it cools and you can cut off areas as you like

I presume you do not pour 60° Celsius hot bee wax on the skin, right?

 

[xrt123]

I presume you do not pour 60° Celsius hot bee wax on the skin, right?

Hyperthermia for radio sensitization? genius

 

[thecarbonionangle]

You do not have to let it “boil”. It starts to soften and melt at lower temps. It can be molded. You just have to play with it.

some other options including moldable bolus (“super stuff”) i mentioned earlier

Moldable Bolus - Radiation Products Design, Inc.

Super Stuff Bolus, Red Rope Wax, Bees Wax Pellets, Dental Base Plate Wax Sheets, Adapt-It Thermoplastic Pellets

www.rpdinc.com

https://www.minnisjournals.com.au/articles/Bolus%20spec%20sept%2012.pdf

You can use a similar technique with some mods and additional materials (dental/ortho putty) for skin collimation with custom lead shielding

Bottomline, this is something cheap and anybody can do it.

 

[thecarbonionangle]

I do 20-22 fx to the ear/nose/pretibial regions, no less. Shame away!

Thats fine, many ways to skin cat!. I actually love cats but had to use that one.

im not dogmatic about fractions but when i can i hypofractionate but def not with proximity to cartilage. For pretebial region, i would use a Freiburg HDR flap if possible. I’m also a big fan of Valencia applicators

 

[scarbrtj]

We have like no resources when it comes to that stuff. I think all we have is superflab or wet gauze and I think neither is particularly good...any ideas?

Why is wet gauze not good. I think it's great here. Pack it in and around all that antihelical region. Then you take your custom wax-mask and put it over that. You scan it. You do a 3D electron plan to make sure the area is covered with the dose you want whilst minimizing dose to distant structures. I'd wind up using a 6/9 MeV 50:50 mix here most times. This mask pic is not the greatest example (was for a much more advanced skin case, and I was treating nodes). When I've got a more superficial target I take a (audio) CD case while the wax is still warm and spray (non-stick) PAM on the case and press it over the wax to get a perfectly flat surface for a nice en face electron beam approach that dose calculates well. I'm too lazy to find a pic of that in my files. I like making these. It's like art class. Here's the rope.

 

[FrostyHammer]

Why is wet gauze not good. I think it's great here. Pack it in and around all that antihelical region. Then you take your custom wax-mask and put it over that. You scan it. You do a 3D electron plan to make sure the area is covered with the dose you want whilst minimizing dose to distant structures. I'd wind up using a 6/9 MeV 50:50 mix here most times. This mask pic is not the greatest example (was for a much more advanced skin case, and I was treating nodes). When I've got a more superficial target I take a (audio) CD case while the wax is still warm and spray (non-stick) PAM on the case and press it over the wax to get a perfectly flat surface for a nice en face electron beam approach that dose calculates well. I'm too lazy to find a pic of that in my files. I like making these. It's like art class. Here's the rope.

I am just not confident that you can get it flush with the lesion without air gaps, especially if you're putting the face upwards in a regular mask. Gravity would tend to make it fall, no?

 

[fiji128]

Here is a case that I have right now that is somewhat similar. 90 year old man with a large BBC going along much of the preauricular skin and crus of the helix.

At the time of simulation I use a sharpie to mark out an area 1.5 cm from the edge of the with BBC boarder. I then wire out the entire area of BBC as closely as possible. Due to the irregular nature of the skin contours fill in and build up the area within the area drawn in with the sharpie with aquasil dental impression epoxy. Then send them through the simulator. Below are pics.

I will end up treating this in 55 Gy in 20 fractions. Dose will be verified on the first fraction with a nanoDots. A thick bolus like this will allow you treat with photons and get good skin dose, which is useful if you need to also cover nearby irregular nodal areas that would be difficult to cover with enface electron fields.

This might be considered a little overkill. Currently I only have photons available for treatment and the patient is unwilling to travel any further. If I was going with an electron field alone (which would be my preference) the bolus would be about half as thick.

There are other more simpler ways of treating. If the lesion is smaller and poorer kps can do 40 Gy in 10 fx (like in folks where transportation is an extreme difficulty or limited life span). Also if you don't have access to epoxy bolus you can just do the best you can with super flab or wet towel and the plan/outcome will likely be fine.

 

[evilbooyaa]

I think we worry too much about bolus conformity. Yes, we should do the best we can, but at end of the day, if you're using enface electrons and low energy, a little air gap here and there isn't going to be the end of the world. As long as the lesion is covered with bolus, I don't think an airgap is going to make a huge difference.

I'd stick with 6MeV to ensure skin dose is good and just go. Wet gauze in the ear may be uncomfortable as well. We have little aquaplast beads that can be put together to create small boluses of custom size and shape.

I would not go lower than 20 fx for this location, and I wouldn't even shame those that went as high as 30+ fx for this location. I would not mess around with a 10fx regimen in this location.

 

[scarbrtj]

I am just not confident that you can get it flush with the lesion without air gaps, especially if you're putting the face upwards in a regular mask. Gravity would tend to make it fall, no?

Unless you can put the patient in a vacuum, there'll always be air gaps
Big air gaps will show in your CT scan, and any air gap effects are theoretically modeled by the TPS which can "see" the air.

 

[scarbrtj]

if you're using enface electrons and low energy, a little air gap here and there isn't going to be the end of the world. As long as the lesion is covered with bolus, I don't think an airgap is going to make a huge difference.

I'd stick with 6MeV to ensure skin dose is good and just go.

this more for students/residents than the old-timers...

Electron therapy is a fascinating topic in and of itself. Really a totally different arena of discussion than X-rays. I like to keep in the back of my mind that 6MeV electrons have about 90% the RBE of a 6MV photon beam; with higher electron energies, there's more RBE... opposite of that in photons where higher energies have less RBE. (We don't talk about RBEs of energies a lot and in practice it may not matter.) And the e-beam penumbras are larger with smaller energies, thus the need for more block margin with smaller energies. (This matters IMHO.) And as far as surface dose and build-up and "worry" over air gaps, at least in theory and AFAIK, the higher the electron energy the more surface build-up and thus higher the surface dose. (Of course the deeper the DMax). So electrons are different in that the higher the energy the less the skin-sparing. However in the ~6-10 MeV range these surface dose %'s change very little; the effect is much more pronounced at ~18 MeV and higher. 6MeV beams have about an 80% surface dose and I like to use at least 1.0 cm bolus with those.

 

[RadOncDoc21]

this more for students/residents than the old-timers...

Electron therapy is a fascinating topic in and of itself. Really a totally different arena of discussion than X-rays. I like to keep in the back of my mind that 6MeV electrons have about 90% the RBE of a 6MV photon beam; with higher electron energies, there's more RBE... opposite of that in photons where higher energies have less RBE. (We don't talk about RBEs of energies a lot and in practice it may not matter.) And the e-beam penumbras are larger with smaller energies, thus the need for more block margin with smaller energies. (This matters IMHO.) And as far as surface dose and build-up and "worry" over air gaps, at least in theory and AFAIK, the higher the electron energy the more surface build-up and thus higher the surface dose. (Of course the deeper the DMax). So electrons are different in that the higher the energy the less the skin-sparing. However in the ~6-10 MeV range these surface dose %'s change very little; the effect is much more pronounced at ~18 MeV and higher. 6MeV beams have about an 80% surface dose and I like to use at least 1.0 cm bolus with those.

Great discussion. What are your thoughts on the photon units derms are using and are we seeing any significant differences regarding what they are doing vs the rad oncs?

I’m curious because we know the physics in detail and can correlate the effects clinically but is there a signal we need to look more into? I’ve never used a photon unit so have no experience in regards to caveats and what they normally would treat. I’m assuming that it’s all superficial basal cells but I haven’t seen one of those in like 2 years. All of my skins end up getting IMRT because of the mess I’m having to clean up (recurrences, large volumes, ECE, etc).

 

[Palex80]

Why is wet gauze not good. I think it's great here. Pack it in and around all that antihelical region.

Wet gauzes are great, especially for cavities. I've used them inside nostrils a few times.


3D-printed boluses are the perfect overkill of course. I presume that in the years to come they will become more popular and we will be able to "scan" the patient's surface with a handheld device that will then send the data to a 3D-printer which will produce the custom bolus in a few hours.

I know that many dentists have stopped taking tooth impressions the old fashioned way and are now using handheld scanners to do that

Until then, do consider whipped cream perhaps?

 

[scarbrtj]

Until then, do consider whipped cream perhaps?

Now that's an air gap!

 

[scarbrtj]

Great discussion. What are your thoughts on the photon units derms are using and are we seeing any significant differences regarding what they are doing vs the rad oncs?

I’m curious because we know the physics in detail and can correlate the effects clinically but is there a signal we need to look more into? I’ve never used a photon unit so have no experience in regards to caveats and what they normally would treat. I’m assuming that it’s all superficial basal cells but I haven’t seen one of those in like 2 years. All of my skins end up getting IMRT because of the mess I’m having to clean up (recurrences, large volumes, ECE, etc).

In reality superficial units should be great... if your target is superficial. A 100kV or 150kV beam can reach ~1cm easily, and penumbras for the cones/applicators they use are very, very small. And bolus needs are non-existent because surface doses are ~100% and the surface is essentially Dmax. When derms have failures, if I were to guess, it's because they treat a crap ton of skin, and even rad oncs will have failures with the best techniques. It's just derms will have more because they treat more. And, perhaps, maybe their prescriptions are janky. Who knows. If you look back at old, old Moss & Cox textbooks, significant chapters were devoted to skin (all treated with sub-200kV energies; electron treatments unheard of course before linacs). This is where, evidently, surgeons (who used to operate on a lot of skin cancers) and "radiation therapists" used to have very good interactions and working relationships.

 

[evilbooyaa]

this more for students/residents than the old-timers...

Electron therapy is a fascinating topic in and of itself. Really a totally different arena of discussion than X-rays. I like to keep in the back of my mind that 6MeV electrons have about 90% the RBE of a 6MV photon beam; with higher electron energies, there's more RBE... opposite of that in photons where higher energies have less RBE. (We don't talk about RBEs of energies a lot and in practice it may not matter.) And the e-beam penumbras are larger with smaller energies, thus the need for more block margin with smaller energies. (This matters IMHO.) And as far as surface dose and build-up and "worry" over air gaps, at least in theory and AFAIK, the higher the electron energy the more surface build-up and thus higher the surface dose. (Of course the deeper the DMax). So electrons are different in that the higher the energy the less the skin-sparing. However in the ~6-10 MeV range these surface dose %'s change very little; the effect is much more pronounced at ~18 MeV and higher. 6MeV beams have about an 80% surface dose and I like to use at least 1.0 cm bolus with those.

Exactly skin dose depends on your individual machine. Our machine's PDD is 85% at skin. My 'standard' for superficial lesions that I don't worry about big depth of invasion is 0.5cm bolus and to the 90% IDL which works out pretty well. TLD confirmation and all that stuff to ensure sufficient skin dose.

 

[metview]

Question about margins for electrons. What margins do you use to account for setup error (PTV) and laterally for penumbra/lateral constriction?

Is reasonable to use 1-1.5 cm PTV margin + 1 cm laterally to account for penumbra/lateral constriction?

 

[scarbrtj]

Question about margins for electrons. What margins do you use to account for setup error (PTV) and laterally for penumbra/lateral constriction?

Is reasonable to use 1-1.5 cm PTV margin + 1 cm laterally to account for penumbra/lateral constriction?

(There is no "laterally" per se in how the electrons are behaving; I suppose you mean "outwardly.") This is an interesting question... the PTV margin concept hasn't been used that often in electron land. But it can be useful. I use a 2cm block margin, minimum, around the area I want to get the Rx dose (because: penumbra, lateral constriction, the vagaries of electrons, etc.). The PTV always, always resides somewhere inside the block margin; if the block margin is at least 2cm around the tx area of interest you can call the PTV anywhere from 0 to 1.9cm in size and I will agree with that

 

[evilbooyaa]

I usually do 1.5-2cm to block edge if I can, but will shrink to block edge of 1cm in high sensitivity areas.

 

[Skindoc83]

What type of margins do you treat For a BCC or SCC? I have very little experience with radiation

 

[scarbrtj]

What type of margins do you treat For a BCC or SCC? I have very little experience with radiation

Your idea of "margins" (if you're a derm) is not the same margin ideas rad oncs have. Ours are more physical/physics-y but we keep the biological/pathological margin ideas in mind too. In general I'd want at least a 0.5-1.0cm margin around what I feel like the extent of the tumor is to get the full prescription dose. The dose is then going to fall off from this edge so that up to 1-1.5cm away from what is felt to be the tumor edge will get some usable therapeutic dose... this is especially true deep to the tumor which may actually be only 1-2mm thick. Below you see a dose distribution of a low energy electron beam on an ideal flat surface; the beam is ~3cm in diameter at the surface (the block defines the beam shape; here the block is a circle 3cm in diameter and you're looking at a coronal dose distribution... the black is the surface and the grey is below the surface). You can see how the dose "bows out" at depth. The "block edge" is at the edge of the color, at the surface; the prescription dose is the red/yellow/orange and green/blue is cooler dose. The usable dose is only maybe ~2cm in diameter at the surface with a 3cm block margin. Even though electrons are a form of superficial therapy they aren't THAT superficial and even a clinic's lowest energy electron beam still has full dose usability over 0 to ~1.5-2.0cm deep as you see here. However electrons do have a quicker dose fall-off at depth versus superficial X-ray machines (NB: electrons are not X-rays). We can add substances/materials between the beam and the patient, on the patient, to "pull the dose up" from going deeper than we'd like.

TL;DR we put a 0.5-1.0cm dose margin around what we think the tumor extent is and give that the full radiation dose

 

[Palex80]

What type of margins do you treat For a BCC or SCC? I have very little experience with radiation

Have a look at the ASTRO guidelines, I find them quite helpful.

Skin Cancer Guideline - American Society for Radiation Oncology (ASTRO) - American Society for Radiation Oncology (ASTRO)

Learn more about the ASTRO guideline on skin cancer on definitive and postoperative radiation therapy for basal and squamous cell cancers of the skin.

www.astro.org

For ELS:
"ELS are typically appropriate for treatment of superficial T1/T2 BCC and cSCC with thicknesses of up to 0.5 cm. When creating the treatment field from the gross tumor volume (GTV) consider margins of 1 cm to provide adequate coverage of microscopic disease spread (0.5 cm for BCC and 0.6 cm for cSCC) and treatment set-up. These margins are recommended with the caveat that it is often not anatomically feasible to have such margins in many critical anatomic locations. ELS treatments planning does not require 3-D reconstruction, although it may be appropriate to obtain 3-D imaging when treating cutaneous targets near critical structures."

 

[elementaryschooleconomics]

(There is no "laterally" per se in how the electrons are behaving; I suppose you mean "outwardly.") This is an interesting question... the PTV margin concept hasn't been used that often in electron land. But it can be useful. I use a 2cm block margin, minimum, around the area I want to get the Rx dose (because: penumbra, lateral constriction, the vagaries of electrons, etc.). The PTV always, always resides somewhere inside the block margin; if the block margin is at least 2cm around the tx area of interest you can call the PTV anywhere from 0 to 1.9cm in size and I will agree with that

Sometimes I just verbatim quote your margin/IMRT/etc posts directly in my department as if they're my own ideas, and people think I'm some sort of RadOnc Sage who has 20 years more experience than I actually do:

"Well, to be clear in our discussions of this case, Dr. Vice Chair, we should be using the term 'outwardly' to reference this electron dose distribution..."

 

[fiji128]

Have a look at the ASTRO guidelines, I find them quite helpful.

Skin Cancer Guideline - American Society for Radiation Oncology (ASTRO) - American Society for Radiation Oncology (ASTRO)

Learn more about the ASTRO guideline on skin cancer on definitive and postoperative radiation therapy for basal and squamous cell cancers of the skin.

www.astro.org

For ELS:
"ELS are typically appropriate for treatment of superficial T1/T2 BCC and cSCC with thicknesses of up to 0.5 cm. When creating the treatment field from the gross tumor volume (GTV) consider margins of 1 cm to provide adequate coverage of microscopic disease spread (0.5 cm for BCC and 0.6 cm for cSCC) and treatment set-up. These margins are recommended with the caveat that it is often not anatomically feasible to have such margins in many critical anatomic locations. ELS treatments planning does not require 3-D reconstruction, although it may be appropriate to obtain 3-D imaging when treating cutaneous targets near critical structures."

I think these guidelines were originally supposed to have dermatology input but astro couldn't get their society to sign on to these guidelines for whatever reason.

 

[scarbrtj]

I think these guidelines were originally supposed to have dermatology input but astro couldn't get their society to sign on to these guidelines for whatever reason.

Here's the reason(s)... "Because dermatologists are the primary users of radiation therapy (RT) for skin cancer,"

In Regard to the American Society for Radiation Oncology Clinical Practice Guidelines on Radiation Therapy for Basal and Squamous Cell Cancers of the Skin

(ASTRO's response)

 

[fiji128]

Here's the reason(s)... "Because dermatologists are the primary users of radiation therapy (RT) for skin cancer,"

In Regard to the American Society for Radiation Oncology Clinical Practice Guidelines on Radiation Therapy for Basal and Squamous Cell Cancers of the Skin

(ASTRO's response)

Ok I remember reading that now. Frankly if you can't get the folks who treat 99.5% of the skin cancers and refer the patient to us for skin cancer RT on board with the guidelines, that really says something not positive about rad onc's mind set in this disease site.

 

[scarbrtj]

‘Holy grail’ nanoparticle injection that treats skin cancer developed by Yale scientists​

 

[elementaryschooleconomics]

‘Holy grail’ nanoparticle injection that treats skin cancer developed by Yale scientists​

Nanoparticles: everyone's favorite "future of medicine" for the past 2 decades and the next 2 decades.

 

[gmsquid]

Ok I remember reading that now. Frankly if you can't get the folks who treat 99.5% of the skin cancers and refer the patient to us for skin cancer RT on board with the guidelines, that really says something not positive about rad onc's mind set in this disease site.

There was derm input. The people who gave input withdrew from authorship.

 

[scarbrtj]

There was derm input. The people who gave input withdrew from authorship.

View attachment 329567

But the rad oncs had written the correct things about skin cancers (they even had a librarian to vet their lit search). Thus the derms, unable to see that the rad oncs were entirely correct in all the skin cancer things, did the only proper thing which was not to sully the guideline with anything incorrect. Expect to see a "Making the Most of Not Having To Hear Dermatologists Babble: A Proposal for a Network-Based Non-melanoma Skin Cancer Network" article next.

 

[medgator]

But the rad oncs had written the correct things about skin cancers (they even had a librarian to vet their lit search). Thus the derms, unable to see that the rad oncs were entirely correct in all the skin cancer things, did the only proper thing which was not to sully the guideline with anything incorrect. Expect to see a "Making the Most of Not Having To Hear Dermatologists Babble: A Proposal for a Network-Based Non-melanoma Skin Cancer Network" article next.

Surprised the urologists didn't withdraw from joint guidelines either

 

[fiji128]

How Private Equity Is Ruining American Health Care

Investors have been buying up doctor’s offices, cutting costs, and, critics say, putting pressure on physicians in ways that hurt patients. The pandemic could make things even worse.

www.bloomberg.com

Crazy how profitable superficial RT can be. Makes you wonder what a typical rad onc practice would look like if we had to be involved with all the patients receiving any type of RT for skin cancer.

 

[Ray D. Ayshun]

How Private Equity Is Ruining American Health Care

Investors have been buying up doctor’s offices, cutting costs, and, critics say, putting pressure on physicians in ways that hurt patients. The pandemic could make things even worse.

www.bloomberg.com

View attachment 337235
Crazy how profitable superficial RT can be. Makes you wonder what a typical rad onc practice would look like if we had to be involved with all the patients receiving any type of RT for skin cancer.

Crazy how cheap a skin graft is compared to what laryngoscopy bills.

 

[TheWallnerus]

How Private Equity Is Ruining American Health Care

Investors have been buying up doctor’s offices, cutting costs, and, critics say, putting pressure on physicians in ways that hurt patients. The pandemic could make things even worse.

www.bloomberg.com

View attachment 337235
Crazy how profitable superficial RT can be. Makes you wonder what a typical rad onc practice would look like if we had to be involved with all the patients receiving any type of RT for skin cancer.

There are ~600K de novo "cancer" RT patients per year in the U.S. being drawn from the ~1.8m new cancer diagnoses per year. This 600K number would include those going to rad onc office for skin ca treatment, but the 1.8m number excludes non-melanoma skin CA. There are ~1m people getting RT for cancer in rad onc offices per year, and that 1m would also include the (small number of) non-melanoma skin cancers getting treated at cancer centers.

But there's something like 3m people a year getting 5m non-melanoma skin cancers per year in the U.S. That's the derms' RT patient pool.

 

[Holemm_ev]

Yeah, we should do the best we can, but at end of the day, if you're using enface electrons and low energy, a little air gap here and there isn't going to be the end of the world. As long as the lesion is covered with the bolus, I don't think an airgap is going to make a huge difference. However, you know, acne is not always based on hormones, so sometimes just a change in diet, or having a skincare routine may solve the problem. When I had acne, I first tried to solve the problem on my own because I thought the doctor will give me antibiotics. I bought just glycolic acid pads that exfoliated my skin gently and I don't know how it treated the acne, here’s their website.

 

[taserlaser]

Canadian practice with catchment of say maybe 2 million: my partner and I who treat skin on alternating weeks with our multi-d clinic (derm, med onc, plastics, gen surg) probably see about 4-5 consults/week for RT skin cases. Post covid bump was quite busy, probably closer to 5-6/week but things have leveled out. Even compared to a handful of years ago where we might have had 2-3 consults/week max, things have gotten busier with the baby boomers aging out even more.

There isn’t a week where I don’t start someone on orthovoltage treatment or some complex H&N VMAT plan. The mohs groups here definitely has more than enough work to go around, and they’re good about referring any adjuvant high risk cases.

 

[TheWallnerus]

Canadian practice with catchment of say maybe 2 million: my partner and I who treat skin on alternating weeks with our multi-d clinic (derm, med onc, plastics, gen surg) probably see about 4-5 consults/week for RT skin cases. Post covid bump was quite busy, probably closer to 5-6/week but things have leveled out. Even compared to a handful of years ago where we might have had 2-3 consults/week max, things have gotten busier with the baby boomers aging out even more.

There isn’t a week where I don’t start someone on orthovoltage treatment or some complex H&N VMAT plan. The mohs groups here definitely has more than enough work to go around, and they’re good about referring any adjuvant high risk cases.

What sort of cases you doing VMATs for

Also what’s your usual ortho Rx and depth and energy

 

[taserlaser]

What sort of cases you doing VMATs for

Also what’s your usual ortho Rx and depth and energy

Few things off the top of my head we’ve been using VMAT for:
- scalps
- neck plans (eg post op or include elective coverage/PNI/base of skull coverage)
- post op axillas/groins

Ortho- we have commissioned at the moment 100kVp, 150 kVp, and 200kVp. Getting a replacement unit soon too and I think we‘re looking at adding either 250 or 300.
- Rx - depends on clinical exam, histology, size, intent, etc. Usual skin prescriptions with a good mix of 30Gy-35Gy/5fr prescribed to surface, some 40Gy/10fr, etc. For coverage depth, depends somewhat on the applicator FSD and size. I’m personally not using 200 a lot for skin unless a pt is particularly frail for a more robust clinical setup with electrons or MV photons.

We have the usual electron equipment too, but they’re used rather sparingly here in favour of ortho a lot in this population since ortho is just too damn convenient for so many things, and exit dose in a lot of case is not a concern/or tight collimation is preferred.

 

[Lamount]

Few things off the top of my head we’ve been using VMAT for:
- scalps

Jokes!