Derm vs. Rad Onc

[OTN]

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I've not had the same experience with scca being radioresistant, even with locally-advanced disease.

Derm where I am is a mixed bag. Most of the dermatologists are very good, and we have a great working relationship with them. There's another fellow, however, who is using the SRT-100 to treat a TON of skin cancer. 17 treatments for everyone, and if you have two lesions, he'll treat one on one day, and the other the other day, for a total of 35 treatments. He fundamentally doesn't understand depth dose penetration, and as a result I've had to salvage more than one case he's treated.

The recent letter from the derm society stating they are the primary users of RT for skin cancer was abhorrent. ASTRO should have smacked them into oblivion.

 

[scarbrtj]

I have no problem with Mohs as first line. Radiation works great for high risk features on path or recurrent. Immunotherapy should be saved. It is not a local therapy. Makes no sense to give it after Mohs unless radiation not possible or has failed.

Im sorry that the rad oncs that you work with have not educated you as such. You are the company you keep!

In my experience I have a great relationship with my referring Derms.

I've not had the same experience with scca being radioresistant, even with locally-advanced disease.

Derm where I am is a mixed bag. Most of the dermatologists are very good, and we have a great working relationship with them. There's another fellow, however, who is using the SRT-100 to treat a TON of skin cancer. 17 treatments for everyone, and if you have two lesions, he'll treat one on one day, and the other the other day, for a total of 35 treatments. He fundamentally doesn't understand depth dose penetration, and as a result I've had to salvage more than one case he's treated.

The recent letter from the derm society stating they are the primary users of RT for skin cancer was abhorrent. ASTRO should have smacked them into oblivion.

I just want to play devil’s (dermatologist’s) advocate for a sec. Humor me. This is for discussion, not offense.
That ASTRO can "smack" dermatology is a Cartmanesque take. As a kid in elementary school I couldn't really smack the lunch lady no matter how disgusting the meal was. Essentially the only skin cancers I've ever seen were referred somehow by a derm. If I could diagnose patients AND treat them too I might find myself treating a lot of those same patients instead of constantly out-referring them.
Who knows more (whatever "more" is) about skin cancer, radiation oncologists or dermatologists?
Mohs has higher cure rates than RT. And RT doesn't hold the lead in cosmesis necessarily either. In short, honest people at best have to say: we should agree to disagree about RT vs Mohs superiorities. And have zero surprise when a derm thinks Mohs is superior. But also derms have a pretty educated opinion about when and when not to Mohs.
And how hard is it, really, to understand depth dose penetration? If you've got a SRT-100 there's not a lot of depth dose penetration knob-tweaking you can do there. It does as it does; it penetrates as it penetrates (and its surface dose is pretty nice). You decide a dose and beam on. It's not rocket science exactly. A lot of XRT may be. But not SRT-100 and its vagaries if there are any. I'd far more say they don't understand fractionation than I would depth dose penetration of an SRT unit. We grant rad oncs leeway that they can be "comfortable not knowing exactly how [they are] curing the cancer." A lot of med onc doesn't fully understand why/how their molecules work. I can grant that non-understanding leeway to a derm too. But how would one truly know what a derm does or doesn't "fundamentally" understand? If a derm had treated 1000 patients on his/her SRT-100...

 

[PhotonBomb]

As usual scar has a rambling post that kind of misses the boat. I said Mohs first line for vast majority.

 

[OTN]

I just want to play devil’s (dermatologist’s) advocate for a sec. Humor me. This is for discussion, not offense.
That ASTRO can "smack" dermatology is a Cartmanesque take. As a kid in elementary school I couldn't really smack the lunch lady no matter how disgusting the meal was. Essentially the only skin cancers I've ever seen were referred somehow by a derm. If I could diagnose patients AND treat them too I might find myself treating a lot of those same patients instead of constantly out-referring them.
Who knows more (whatever "more" is) about skin cancer, radiation oncologists or dermatologists?
Mohs has higher cure rates than RT. And RT doesn't hold the lead in cosmesis necessarily either. In short, honest people at best have to say: we should agree to disagree about RT vs Mohs superiorities. And have zero surprise when a derm thinks Mohs is superior. But also derms have a pretty educated opinion about when and when not to Mohs.
And how hard is it, really, to understand depth dose penetration? If you've got a SRT-100 there's not a lot of depth dose penetration knob-tweaking you can do there. It does as it does; it penetrates as it penetrates (and its surface dose is pretty nice). You decide a dose and beam on. It's not rocket science exactly. A lot of XRT may be. But not SRT-100 and its vagaries if there are any. I'd far more say they don't understand fractionation than I would depth dose penetration of an SRT unit. We grant rad oncs leeway that they can be "comfortable not knowing exactly how [they are] curing the cancer." A lot of med onc doesn't fully understand why/how their molecules work. I can grant that non-understanding leeway to a derm too. But how would one truly know what a derm does or doesn't "fundamentally" understand? If a derm had treated 1000 patients on his/her SRT-100...

I'm not saying it's hard to understand depth dose penetration, and I'm sure many dermatologists treat with superficial RT just fine. I also agree that Mohs is the standard of care, and that's what I tell patients.

However, if another specialty tries to tell us that they- not us- are the primary users of radiation for a particular malignancy, then I would hope the response from ASTRO would be significant. If not, then what, exactly, do they do here?

(Look, scar, a link! I did it!)

 

[scarbrtj]

I'm not saying it's hard to understand depth dose penetration, and I'm sure many dermatologists treat with superficial RT just fine. I also agree that Mohs is the standard of care, and that's what I tell patients.

However, if another specialty tries to tell us that they- not us- are the primary users of radiation for a particular malignancy, then I would hope the response from ASTRO would be significant. If not, then what, exactly, do they do here?

(Look, scar, a link! I did it!)

Well they don't do much. I could write a pretty nice rambling post about how ASTRO seems to skew more anti-rad onc than pro-rad onc. Kind of rad onc's frenemy. But derms being "primary" ie principal users of RT (for skin CA, and maybe one day even otherwise) may simply be an inelegant, and triggering for us, statement of fact.

 

[deleted950463]

Well they don't do much. I could write a pretty nice rambling post about how ASTRO seems to skew more anti-rad onc than pro-rad onc. Kind of rad onc's frenemy. But derms being "primary" ie principal users of RT (for skin CA, and maybe one day even otherwise) may simply be an inelegant, and triggering for us, statement of fact.

it’s the same thing that vascular surgeons are the primary operator in the endovascular large vessel space despite IRs invented angiography etc. whoever controls the patient control the modality. Nobody “owns” the modality but some docs own their patients. Be that doc.

 

[evilbooyaa]

I believe mohs to be the gold standard and think immunotherapy, like cepilimumab, shows a lot of promise and will likely be standard adjuvant for cases that can’t be cleared with mohs.

Bolded I (and most, probably) agree with.

The rest of that, no. cSCC is NOT melanoma (which is not done for positive margins which is what MOHS leaves with). And Cemiplimab is NOT ipi/nivo. Cemiplimab has a 50% response rate in advanced disease: PD-1 Blockade with Cemiplimab in Advanced Cutaneous Squamous-Cell Carcinoma. - PubMed - NCBI

RT has a higher than 50% response rate.

 

[Skindoc83]

Bolded I (and most, probably) agree with.

The rest of that, no. cSCC is NOT melanoma (which is not done for positive margins which is what MOHS leaves with). And Cemiplimab is NOT ipi/nivo. Cemiplimab has a 50% response rate in advanced disease: PD-1 Blockade with Cemiplimab in Advanced Cutaneous Squamous-Cell Carcinoma. - PubMed - NCBI

RT has a higher than 50% response rate.

Thats great to know. In the rare instances where I have to pass a patient on for adjuvant radiation after mohs, I have been frustrated with the outcomes. Sadly I suspect these were always going to be highly aggressive and refractory to therapy but I hold out hope that immunotherapy will one day be that magic bullet. And for what it’s worth. I do discuss radiation with referral to rad onc with all of my patients as a possible alternative to mohs, but almost no one ever takes me up on that.

As for derm claiming to be the authority on treating NMSC with radiotherapy I suspect they are correct in that the vast majority of NMSC being treated with radiotherapy is being done by dermatologists. Now as to who is treating them most effectively, I highly suspect it is not derm. I think it is inappropriate for these companies to market these machines to dermatologists. They promote it as just point and shoot since most of the parameters are fixed and unchangable. I remember about 10 years ago when dermatologists in FL were installing machines in their office, lead lining and all, and having radiation oncologists come in to administer treatments. I believe this violated Starks law. I suspect this is when they started marketing dumbed down devices straight to dermatologists.

 

[FrostyHammer]

I certainly agree in principle but this might be too confident and we need to watch the left flank

https://ascopubs.org/doi/10.1200/JCO.18.01982

This doesn't really tell me anything different. Yes, med oncs think million dollar immunotherapy agents are the best and can replace local therapy, but that's a referral (lack thereof) problem and not an issue with available data. Then again, I feel like many med oncs don't really care about data and want to throw immunotherapy at everyone that shows up in their clinics. All the while, insurance companies are instead fixating on denying us IMRT for lung/esophagus while bleeding money from med onc use of off label immunotherapy...how laughable.

 

[PhotonBomb]

Lol scar. Makes zero sense to cite what he cited. Immunotherapy for tiny asymptomatic brain mets in order to delay or lessen the amount of SRS we need to do is a whole different ball game than local disease with local risk factors

This guy just doesn’t get it

 

[doctalaughs]

Interesting conversation. I’ve being doing general medical Derm >15 years and probably treat or triage/refer about 3000 tumors a year in my own patients.

The thing missed is that no single modality is the right choice for everything and Mohs (or radiation) is not the best. Most skin cancers are not aggressive and if I had to guess my numbers (out of those ~3000):

- 2000 Treated with EDC or topical
- 500 excision
- 450 Mohs referrals
- 50 “other” (referred for xrt, PDT, injecting interferon/Mtx/bleo, hedgehog inhibitor etc).

So my practice you can see only a handful (less than 1 percent) get radiation with my (very appreciated and skillful) radonc colleagues.

I suspect that derms who do Mohs themselves, or bought a machine probably have wildly different numbers... but I doubt they could prove better outcomes. Neither is it practical for the very common scenario where a patient has 5-10 non-aggressive tumors every 3 months. IMO one of the main purposes of a medical dermatologist is knowing how aggressive tumors are and which treatments are appropriate. And if you are a dermatologist radiating everything (or doing Mohs on everything) ... you are probably unethical.

 

[PhotonBomb]

good post

'And if you are a dermatologist radiating everything (or doing Mohs on everything) ... you are probably unethical.'

and we know this definitely happens with some derms..... I don't think some derms understand you don't need to do a big mohs and a plastics recon for a 0.5 cm BCC in an 80 year old. I've seen it. They justify it with 'low but nonzero metastatic potential and chance for significant growth in long term'.

it's like when people were taking out every single 2 mm gleason 6 single core prostate.

 

[evilbooyaa]

While I think there is some distinction between basals, run-of-the-mill cutaneous squamous cell carcinomas (cSCCs) in non-sensitive locations, run-of-the-mill basals or cSCCs in sensitive locations, and aggressive cSCCs (and the rare basal that has actually biologically proven it is aggressive), I do agree with the rest of the above 2 posts.

 

[doctalaughs]

good post

'And if you are a dermatologist radiating everything (or doing Mohs on everything) ... you are probably unethical.'

and we know this definitely happens with some derms..... I don't think some derms understand you don't need to do a big mohs and a plastics recon for a 0.5 cm BCC in an 80 year old. I've seen it. They justify it with 'low but nonzero metastatic potential and chance for significant growth in long term'.

it's like when people were taking out every single 2 mm gleason 6 single core prostate.

If it’s truly a small BCC then by definition it shouldn’t end up being a huge Mohs and reconstruction (unless they are incompetent or not reading their margins correctly).... in fact- if it ends up huge they were probably right in the first place to do it.

I think more commonly I see doing tons of tiny Mohs on tiny non-aggressive cases (that don’t need it). I suppose this can be defended as “the best cure rate” although imo there is little difference/benefit for these cases to do Mohs (and there is a societal+ patient time/money cost). On the other hand- the few dermatologists (and I think it’s actually a very small #) radiating a large percentage of their cases are probably purely greedy and unethical.

 

[scarbrtj]

Lol scar. Makes zero sense to cite what he cited. Immunotherapy for tiny asymptomatic brain mets in order to delay or lessen the amount of SRS we need to do is a whole different ball game than local disease with local risk factors

This guy just doesn’t get it

I bring out the intentional obtuseness in you. Someone said that’s it’s tough to believe immunotherapy agent X will achieve high LCs. It’s not tough to believe immuno agent Y might achieve high LCs in the future one day though given current trends. Radiation (and surgery) has achieved about the highest LCs it’s gonna get in most disease sites. Especially in NMSCs. Biologics have nothing but room for improvement and show LC potential(s).

But on another note it’s perspective-granting to realize the average derm sees about ten times more cancers a year than the average rad onc.

 

[radiation]

I bring out the intentional obtuseness in you. Someone said that’s it’s tough to believe immunotherapy agent X will achieve high LCs. It’s not tough to believe immuno agent Y might achieve high LCs in the future one day though given current trends. Radiation (and surgery) has achieved about the highest LCs it’s gonna get in most disease sites. Especially in NMSCs. Biologics have nothing but room for improvement and show LC potential(s).

But on another note it’s perspective-granting to realize the average derm sees about ten times more cancers a year than the average rad onc.

I think its more helpful to think of each modality as being complementary to each other rather one eventually replacing the other. Certainly one of the dominant trends in immunotherapy right now is finding the best combination with radiation.

ClinicalTrials.gov

clinicaltrials.gov

If they are eventually able to find improved disease outcomes with rational checkpoint/RT combinations, the ideal situation for radiation oncology would be to find radiation dosing schedules that combine with immunotherapy that are nontoxic and easily deliverable. This is definitely pie in the sky thinking, but its not inconceivable that if a nontoxic radiation regimen were found that complemented immunotherapy, every pt getting immunotherapy would deserve a consultation with a radiation oncologist.

 

[scarbrtj]

I think its more helpful to think of each modality as being complementary to each other rather one eventually replacing the other. Certainly one of the dominant trends in immunotherapy right now is finding the best combination with radiation.

ClinicalTrials.gov

clinicaltrials.gov

If they are eventually able to find improved disease outcomes with rational checkpoint/RT combinations, the ideal situation for radiation oncology would be to find radiation dosing schedules that combine with immunotherapy that are nontoxic and easily deliverable. This is definitely pie in the sky thinking, but its not inconceivable that if a nontoxic radiation regimen were found that complemented immunotherapy, every pt getting immunotherapy would deserve a consultation with a radiation oncologist.

There is a dominant trend for increased hunting of XRT+immuno regimens, but I'm not sure there's a trend of increased success with XRT+immuno regimens insofar as a 2+2=5 effect (PACIFIC doesn't match that IMHO) if you catch my drift. It seems immuno adds on top of already pre-existing (chemo)XRT outcomes. Is there additive synergy? The jury is very much out. But what the jury is not out on is a trend of improved locoregional control with immuno... it's not Moore's law-ish, but if you use your imagination you can imagine that new agents will keep coming out (be they immuno or something else?) and keep improving things. (One reason I bring up Moore's law is that survival has been dramatically improving in cancer the last 50 years. I go on record as saying radiation has contributed very little to this. I don't believe we can "Moore's law" RT, for survival, but there is potential in biologics. Increased survival comes, partly, from increased LC.) Is radiation "helpful" to immuno? No one really knows if we're honest. I don't know if anyone else has had this epiphany with the herceptin data e.g. but when those curves first came out I thought "wow we may not need XRT for these ladies." And thus I guess that's why there's a trial (trials?) looking at instead of XRT being "complementary" to immuno or vice versa, having immuno replace the RT. The most nontoxic RT regimen is the one ungiven. And granted we both may be pie-in-skying with both our takes.

 

[PhotonBomb]

I do agree with you on the fact that systemic therapy can only improve and improve in terms of local control whereas local therapies like RT and surgery are essentially maxed out. improvemnts in systemic therapy have essentially wiped us out of the majority of the GI game and certainly melanoma. most things other than head and neck are definitely at risk long term.

 

[radiation]

There is a dominant trend for increased hunting of XRT+immuno regimens, but I'm not sure there's a trend of increased success with XRT+immuno regimens insofar as a 2+2=5 effect (PACIFIC doesn't match that IMHO) if you catch my drift. It seems immuno adds on top of already pre-existing (chemo)XRT outcomes. Is there additive synergy? The jury is very much out. But what the jury is not out on is a trend of improved locoregional control with immuno... it's not Moore's law-ish, but if you use your imagination you can imagine that new agents will keep coming out (be they immuno or something else?) and keep improving things. (One reason I bring up Moore's law is that survival has been dramatically improving in cancer the last 50 years. I go on record as saying radiation has contributed very little to this. I don't believe we can "Moore's law" RT, for survival, but there is potential in biologics. Increased survival comes, partly, from increased LC.) Is radiation "helpful" to immuno? No one really knows if we're honest. I don't know if anyone else has had this epiphany with the herceptin data e.g. but when those curves first came out I thought "wow we may not need XRT for these ladies." And thus I guess that's why there's a trial (trials?) looking at instead of XRT being "complementary" to immuno or vice versa, having immuno replace the RT. The most nontoxic RT regimen is the one ungiven. And granted we both may be pie-in-skying with both our takes.

Your points are certainly well taken. But the idea that Moore's law only applies to single modality therapies is somewhat misleading. It is equally plausible that the better systemic therapies get, the more opportunities there will be to combine them with radiation. The most successful treatments for locally advanced disease is multi-modality. And while there is certainly limited scenarios with immuno is being tested as a replacement, these are far outnumbered by combination approaches.

Whether or not it actually pans out, we will see. But why not root for such a thing? We should all be glad that they are hunting for this, it benefits all of us, including pts

This is semantics, since I understand what you were trying to say, but side note for nerds only: in the strictest sense of the term, synergy is incredibly hard to demonstrate. There are no clinical demonstrations of true synergy in cancer treatments that I am aware of. This is because when combining therapies, most people are maxing out individual therapies since cure rates are almost never 100%. To demonstrate true synergy, you need to show each treatment has a greater individual effect when given together, and that often requires reducing doses. There is some boring math, but for a dumbed down example: lets say drug A gives cure rate of 40% and drug B gives cure rate of 40%. For synergy, if you give them together you need cure rate of >80%. If Drug A gives a cure rate of 51%, and Drug B gives cure rate of 50% and together they give a 99% cure rate, that would still not be true synergy. So synergy almost never happens clinically since you would almost never give a lower doses just show synergy. Seminal paper this here:

Drug Combination Studies and Their Synergy Quantification Using the Chou-Talalay Method

This brief perspective article focuses on the most common errors and pitfalls, as well as the do's and don'ts in drug combination studies, in terms of experimental design, data acquisition, data interpretation, and computerized simulation. The Chou-Talalay method for drug combination is based on...

cancerres.aacrjournals.org

Is it possible to “determine” synergism in clinical trials or in clinics? The answer is generally no for the disease per se (e.g., cancer or AIDS). This is based on scientific, practical, and ethical reasons