Another case discussion... Anal boost

[KHE88]

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Going along with the theme of discussing actual day-to-day work, what is everyone one doing for anal boosts?

Sequential? SIB?

Is anyone taking the primary to anything more than 5400? I have a lady with a very large anal mass, about 7 cm longitudinally. I am debating getting an MRI towards the end of treatment and adding a fraction or two to the gross disease + 7mm. I don't know about pushing all the way to 5940. Anybody routinely going higher than 5400 or treating 5940 to a large volume?

Also curious what people are using for margins. I typically dose paint with a 1.5 cm margin around the primary to 5400 and a 2 cm margin to 5040.

 

[xrthopeful]

Some people take T3 and T4 to 59.4 and the NRG is looking at this in their next trial. I think it’s reasonable.

 

[medgator]

Some people take T3 and T4 to 59.4 and the NRG is looking at this in their next trial. I think it’s reasonable.

I do. Have had a few failures even at 4-5 cm tumors only going to 54.

 

[metview]

What does everyone do for the elective nodes? 42 Gy for T1/T2 and 45 Gy for T3/T4 or do you push higher to 50.4 Gy?

 

[Haybrant]

Don’t do it, you’ll own side effects bc you think you need more dose but you don’t really know. I’ve cured 2 guys w 7-8cm tumors going max 54.

 

[RickyScott]

I have been treating sequentially with all nodes to 30-36(if node+) and then a cone down to gross disease to 50-59. Haven’t used much sib, except in some very frail pts where I have taken nodes at lower than 180.

 

[medgator]

I do. Have had a few failures even at 4-5 cm tumors only going to 54.

Don’t do it, you’ll own side effects bc you think you need more dose but you don’t really know. I’ve cured 2 guys w 7-8cm tumors going max 54.

🙂

 

[xrthopeful]

I hate sequential under all circumstances

 

[ramsesthenice]

Don’t do it, you’ll own side effects bc you think you need more dose but you don’t really know. I’ve cured 2 guys w 7-8cm tumors going max 54.

I second this. Dose escalated boosting has been looked at and is not compelling.

I also mostly do sequential but because like Ricky I keep the dose to elective nodes lower (36). I worry about the fraction sizes at that dose. When I do SIB, I kick those up to 45.

 

[ramsesthenice]

What does everyone do for the elective nodes? 42 Gy for T1/T2 and 45 Gy for T3/T4 or do you push higher to 50.4 Gy?

I never understand why people try to get cute with anal cancer. Why would you do this? Do you think microscopic nodal disease from a 4 cm primary takes more dose to kill than microscopic nodal disease from a 1 cm tumor? We don’t do this in most other diseases, so why do it here? I would say make life easy on your self and pick one somewhere between 36-45 for elective volumes.

 

[Palex80]

I do. Have had a few failures even at 4-5 cm tumors only going to 54.

Same for me! T3-T4 get 59.4 Gy. I fractionate with 1.8 Gy/d, no SIB.

On a side note: I've see 2 cases of failures in the skin of the buttocks, within a few cm of so of the anal margin. I presume it was lymphovascular spread.
I think this has to do with IMRT becoming s.o.c. In the old days you would treat open fields up to 30 Gy (at least), meaning that all your buttocks received the full dose. Nowadays with IMRT, dose in those areas may be considerably lowew, so giving a generous CTV to the skin around the anal margin for big& lower lying tumors seems prudent.

 

[BobbyHeenan]

I pretty much stick to 0529 dosing and trained that way and did my boards case that way.
Don’t see anything wrong with sequential boost though.

I have done a case like you said and used a 5.4 gy tunor boost after 54 Gy 0529 style. Has controlled disease but poor sphincter.

No clue as to what the right answer is here. Maybe slightly better tumor control at cost of worsening sphincter control.

 

[deleted1002574]

Going higher seems fraught.

0529 outcomes are good. Better than historic data from RTOG, which used higher doses. Not sure why go higher? Control rate is darn high with 0529 doses.

Nigro did 30/10. 60 Gy seems excessive, and sphincter function is correlated with dose. Would be careful and a bit tough to explain with no evidence for escalation.

 

[radoncradonc]

In the UK, they are dose escalating beyond 54Gy

 

[RickyScott]

l

m

In the UK, they are dose escalating beyond 54Gy

I have gone above 54 and I have also had some long term side effects. I treat a lot of this disease. Argument against dose escalation is that as Nigro trial 30 gy @ 2 gy fraction showed us, vast majority of anal cancers are cured with a low dose and there likely is diminishing return after certain point when using 5 fu/mitmoycin. Dose escalation likely to have role in pts who are on xelodabecause can’t tolerate mito.

Imrt was game changer for this disease in avoiding breaks due to skin toxicity (unless you were using McGill technique with 4 field diamond half beam block matched to superior ap/pa and elections.) Failures are very rare in pts who do not break in m experience.

My issue with Kachinics rtog trial is that the volumes and expansion were way too large.

 

[deleted1002574]

Way too big volumes, illogically big
Despite that, toxicity outcomes good. If using reasonable volumes, you’re right they do so well.

l

m

I have gone above 54 and I have also had some long term side effects. I treat a lot of this disease. Argument against dose escalation is that as Nigro trial 30 gy @ 2 gy fraction showed us, vast majority of anal cancers are cured with a low dose and there likely is diminishing return after certain point when using 5 fu/mitmoycin. Dose escalation likely to have role in pts who are on xelodabecause can’t tolerate mito.

Imrt was game changer for this disease in avoiding breaks due to skin toxicity (unless you were using McGill technique with 4 field diamond half beam block matched to superior ap/pa and elections.) Failures are very rare in pts who do not break in m experience.

My issue with Kachinics rtog trial is that the volumes and expansion were way too large.

 

[ramsesthenice]

In the UK, they are dose escalating beyond 54Gy

On trial yes. But there is good reason for pause. the whole point of primary chemorads is organ preservation and you are playing with fire pushing the dose without good evidence it helps. Might consider waiting until you have data showing it helps before jumping in headlong.

 

[xrthopeful]

Now we are on to something interesting. The 0529 margins suck. Illogical.

Interested in how you guys alter practice in your margins - please share!

A 2.5 cm CTV is a joke.

 

[Reaganite]

Good discussion! For me, cure has been more about patient compliance than boost dose. Knock on wood, haven't seen any failures in my compliant private patients usually going no higher than 54 Gy for big lesions. County patients who miss multiple treatments and don't take their xeloda or miss a dose of MMC--recurrence rate close to 100% even going to 59.4 for smaller lesions.

 

[BobbyHeenan]

Now we are on to something interesting. The 0529 margins suck. Illogical.

Interested in how you guys alter practice in your margins - please share!

A 2.5 cm CTV is a joke.

I'm 100% guilty of using 0529 dosing scheme, constraints, yet cutting down on the margins.

When an anal canal tumor 2-3 cm in size is then expanded fully to 0529 rec's and you've got margins way out into gluteal fat, I trim it up some. Also trim it up some when low lying small bowel (especially post hysterectomy females).

I'd say on average I use GTV (CT w/ IV contrast PET) plus closer to 1.5 cm to CTV for anal canal. I also don't typically take the nodal CTV to include the whole nodal chain as rec'd on 0529 (ie if one external iliac node involved teh whole of the external iliac area per protocol gets the whole escalated dose...I don't typically follow that paradigm and just dose escalate the node + 1cm). Just as mentioned above, anal margin tumors that seem to be spreading on skin I"m more generous and closer to 0529 rec's due to fear of skin spread.

My experience is just as above - if you can keep them off of breaks they do well. Though that can be challenging with indigent HIV patients without access to good hygiene products/techniques like sitz baths or regular showers.

 

[PhotonBomb]

i hate the big margins on 0529 but must admit I have not deviated yet.

i hope the next nrg trial better defines these.

 

[Mandelin Rain]

Oh, I deviate.

1-1.5 cm and I subtract further if they make no sense. I TLD every first fraction. Put 2-3 on the anus and make sure it’s within 5% of expected.
No need to treat the genitals to prescription dose.

 

[KHE88]

Great discussion. I was worried I was asking a stupid question. Glad others are just as confused as I am, I suppose.

I frequently cannot get PET scans on these patients, and I'm stuck trying to delineate the GTV based on the CT and MRI. This worries me that I am seriously over contouring, and a 2 cm expansion on a 6-7 cm primary creates an enormous 5400 volume, with a lot of small bowel just getting blasted with 5400.

This is why I dose painted 5400 to 1.5 and 5040 to 2.0, but now I'm thinking I will reduce this to 1.25 cm and 1.75 cm. Wish we had some better data on this.

The points about perianal skin margin are well taken.

Next question, do you all bolus inguinals? For instance if you have a very thin patient, as these patients often are, with a gross inguinal node basically right at the skin surface due to lack of subQ fat? Or do you all feel nature of IMRT/VMAT doses skin well enough?

 

[medgator]

You can't get a PET approved in anal scc? Even my medicaid pts usually get one

 

[PhotonBomb]

Chris crane has some great info on this on mednet. Search anal cancer and read them all, I learned a lot from his posts.

 

[deleted1002574]

Yeah, I think VMAT covers skin adequately. And those margins sound very reasonable.

For boost, I contoured GTV, and add 1cm sup and inf. Then extend the volume to include the whole MRE and sacral hollow. Then 0.5-1 PTV based on what kind of imaging and competency of RTTs. Used to add differential margin for ‘gweenals but got away from that with better set up/immobilization.

Great discussion. I was worried I was asking a stupid question. Glad others are just as confused as I am, I suppose.

I frequently cannot get PET scans on these patients, and I'm stuck trying to delineate the GTV based on the CT and MRI. This worries me that I am seriously over contouring, and a 2 cm expansion on a 6-7 cm primary creates an enormous 5400 volume, with a lot of small bowel just getting blasted with 5400.

This is why I dose painted 5400 to 1.5 and 5040 to 2.0, but now I'm thinking I will reduce this to 1.25 cm and 1.75 cm. Wish we had some better data on this.

The points about perianal skin margin are well taken.

Next question, do you all bolus inguinals? For instance if you have a very thin patient, as these patients often are, with a gross inguinal node basically right at the skin surface due to lack of subQ fat? Or do you all feel nature of IMRT/VMAT doses skin well enough?

 

[KHE88]

You can't get a PET approved in anal scc? Even my medicaid pts usually get one

I have a huge population with no insurance at all. Even getting a PET on someone with decent insurance in a rural area is a challenge as we don't have a scanner and it comes on a truck a few times a month.

So I could probably get a PET, maybe, in 1-2 months. I am not going to delay a curative treatment that long and just boost any suspicious nodes assuming they are involved.

Things you take for granted practicing in a highly populated area.

 

[KHE88]

Yeah, I think VMAT covers skin adequately. And those margins sound very reasonable.

For boost, I contoured GTV, and add 1cm sup and inf. Then extend the volume to include the whole MRE and sacral hollow. Then 0.5-1 PTV based on what kind of imaging and competency of RTTs. Used to add differential margin for ‘gweenals but got away from that with better set up/immobilization.

Wait you boost the whole mesorectum to 5400? I treat it, but only to 4500 and boost based off the expansion from GTV.

 

[deleted1002574]

The MRE surrounding the GTV, not the entire MRE top to bottom. Is that what you are asking ?

 

[Krukenberg]

The thing I like about sequential boost is you can treat high pelvic nodes to 30-36 gy. Chris crane and Joel Tepper had a great debate about this on MedNet and I agree that the best way to lower side effects is to reduce dose, not some fancy tech. I know the most common tox is rectal and this wouldn’t change it, but you can’t convince me that lowering dose to small bowel won’t make a difference across populations.

It is more annoying to sign multiple plans though.

 

[medgator]

The thing I like about sequential boost is you can treat high pelvic nodes to 30-36 gy. Chris crane and Joel Tepper had a great debate about this on MedNet and I agree that the best way to lower side effects is to reduce dose, not some fancy tech. I know the most common tox is rectal and this wouldn’t change it, but you can’t convince me that lowering dose to small bowel won’t make a difference across populations.

It is more annoying to sign multiple plans though.

Not a bad thought, but with imrt/vmat, are people really getting that bad of gi toxicity going to 45? Biggest issue continues to be skin toxicity at the primary site for me, but that's just part of how things go and is addressed with hygiene, pt instruction etc

 

[deleted1002574]

The thing I like about sequential boost is you can treat high pelvic nodes to 30-36 gy. Chris crane and Joel Tepper had a great debate about this on MedNet and I agree that the best way to lower side effects is to reduce dose, not some fancy tech. I know the most common tox is rectal and this wouldn’t change it, but you can’t convince me that lowering dose to small bowel won’t make a difference across populations.

It is more annoying to sign multiple plans though.

I’ve been SIB for my whole career but... I’d have to agree that 30.6 Gy in 17 to elective regions has to have less toxicity than 45/30, there is no doubt, and wouldn’t need a study to convince me. Never thought about it that way.

 

[Krukenberg]

I’ve been SIB for my whole career but... I’d have to agree that 30.6 Gy in 17 to elective regions has to have less toxicity than 45/30, there is no doubt, and wouldn’t need a study to convince me. Never thought about it that way.

And chris crane and tepper both agreed they’ve never seen a failure in a 30-36 gy field. Crane does the higher elective dose just because it’s the only way to SIB.

 

[evilbooyaa]

We usually do sequential. I like the cone-down although the skin toxicity is the main issue.

Stop at 55-59 depending on initial T-stage and response during therapy.

 

[seper]

While local control rates for T3/T4 tumors at 54 Gy are not ideal, going to 60 Gy does not improve them further. I believe there was a 4-arm European study that has addressed this issue.

 

[medgator]

While local control rates for T3/T4 tumors at 54 Gy are not ideal, going to 60 Gy does not improve them further. I believe there was a 4-arm European study that has addressed this issue.

And some of us still treat IIIA/B lung to 63-66, and, gulp, dose-escalate inoperable esophageal CA.

Guilty on all counts. The great thing is I follow my pts long term

 

[Krukenberg]

In the UK, they are dose escalating beyond 54Gy

they’re also running a trial of dose de-escalation

 

[evilbooyaa]

While local control rates for T3/T4 tumors at 54 Gy are not ideal, going to 60 Gy does not improve them further. I believe there was a 4-arm European study that has addressed this issue.

Correct. ACCORD 03 did not show benefits to induction chemo or dose escalation: Induction chemotherapy and dose intensification of the radiation boost in locally advanced anal canal carcinoma: final analysis of the randomized U... - PubMed - NCBI

 

[deleted1002574]

Correct. ACCORD 03 did not show benefits to induction chemo or dose escalation: Induction chemotherapy and dose intensification of the radiation boost in locally advanced anal canal carcinoma: final analysis of the randomized U... - PubMed - NCBI

The abstract is like a scarb post. Hard to understand but probably has some information in it.

Did all 4 arms do induction? If so, I’d disregard the whole thing.

 

[PhotonBomb]

ACCORD is a little hard to interpret. I agree the role for dose escalation is far from proven. I am glad the UK trial is looking at it ( they are looking at DE-ESCALATION too in another trial). NRG also going to look at it again for escalation.

to me anal cancer dose changes still a potential open question.

We know that lung and esophageal escalation is DOA in good pure trials.

some people can still choose to escalate, because of 'gestalt' but you can be sure they will stop once that stops meaning one extra OTR payment!! (once otrs don't matter).

 

[evilbooyaa]

The abstract is like a scarb post. Hard to understand but probably has some information in it.

Did all 4 arms do induction? If so, I’d disregard the whole thing.

It's written somewhat awkwardly, agreed, but it's a 2x2 factorial with Induction chemo as one of the expermiental variables and dose escalation as the other experimental variable.

Although the 'standard' on this was 60Gy (45+15) and high-dose was 65-70 (45+20-25), which is different than what most are saying on here about a difference between 54 and 60.

 

[deleted1002574]

I’m much more curious about 50-54 vs 60-64. Another trial that I wonder why was done. Who is doing 60 “standard”?

 

[medgator]

I’m much more curious about 50-54 vs 60-64. Another trial that I wonder why was done. Who is doing 60 “standard”?

Did anyone ever treat their stage IIIA nsclc pts to 74 with chemo? I sure as hell never have.

 

[seper]

Bunch of people I've worked with did 74 Gy. I've also heard in late 2000's UPMC had their "standard protocol" to do 79.2 Gy/44 for stage III lung. Scary to think how many people have died prematurely.

Did anyone ever treat their stage IIIA nsclc pts to 74 with chemo? I sure as hell never have.

 

[deleted1002574]

Not 44 fractions. They used 2.1 Gy / fx for stage III lung to 78.7 Gy - they may have published?
I did 74 Gy once in practice when it was still an approved dose. 3D plan, and his back got SCORCHED.

 

[Krukenberg]

Relating to the elective dose: