pT4N0 larynx - post op radiation volume

[BobbyHeenan]

I have a patient s/p total laryngectomy and bilateral neck dissection (0/19 on one side, 0/23 nodes on the other side). Path showed a ~4 cm tumor, extension through cartilage into soft tissues. Margins negative.

I'm planning post op radiation; classically the neck/nodes would have been treated, but I'm thinking no specific targeting of his nodes (ie just treat his operative bed to 60 Gy).

Any thoughts here? One of my head/neck attendings would have definitely covered nodes, and another probably wouldn't have. Just curious what you all think.

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[medgator]

With post op Tx, you're going to end up covering part of levels 2-4 bilaterally anyways I would imagine

 

[BobbyHeenan]

With post op Tx, you're going to end up covering part of levels 2-4 bilaterally anyways I would imagine

Yeah, I bet with VMAT on that operative bed getting 60 probably a lot of level II-IV will get 40-50 I'd say.

 

[seper]

I'd also cover B/L supraclav and the uppermost mediastinum to 54 Gy - not dissected

 

[scarbrtj]

Still doing ENI for all XRT-worthy postop HN cases (unless you know something I don't). The LR risk is high enough to warrant it, regardless the "orgy" of negative nodes here. IMHO!

 

[mavrik13]

Would only treat the operative bed, without ENI. I'm not aware of any data either way and would love to hear it. Rationale for not doing ENI is that if first echelon nodes are negative, I'd expect a <5% probability of nodes outside of dissected area to have disease.

 

[medgator]

Still doing ENI for all XRT-worthy postop HN cases (unless you know something I don't). The LR risk is high enough to warrant it, regardless the "orgy" of negative nodes here. IMHO!

and with IMRT, I believe the morbidity from ENI in post-op cases is significantly better than historical data in the 2D/3D era, pushing the calculus towards ENI

 

[scarbrtj]

Would only treat the operative bed, without ENI. I'm not aware of any data either way and would love to hear it. Rationale for not doing ENI is that if first echelon nodes are negative, I'd expect a <5% probability of nodes outside of dissected area to have disease.

Less than 5% wouldn't be my metric. Here's why:
1) Pathological examinations are not as comprehensive as we think, and while this guy had a lot of LNs dissected, at the end of the day still only about 10-15% of his neck LNs have been sampled...
2) So the risk for (under-)sampling error might be high even with good dissections...
3) Especially given the fact that ~40% of cT4N0 laryngeal patients wind up having N+ disease at surgery...
4) And this guy had a tumor showing aggressive local behavior, which portends for a tumor that "knows" how to go to nodes too...
5) Plus, he had surgery; given likely microscopic local disease, who knows what kind of loop surgery throws re: screwing up the local lymphatics making a regional nodal risk higher post-surgery vs pre-surgery
6) Finally, how would you feel if you saw a patient back with a pT4N0 laryngeal who you'd given partial neck XRT of 60 Gy now with nodal, in- or edge-of-field recurrence? Me... I'd feel stupid.

Let pathological nodal bulk (±ECE) govern chemoRT/RT decisions, not ±ENI decisions.

 

[scarbrtj]

and with IMRT, I believe the morbidity from ENI in post-op cases is significantly better than historical data in the 2D/3D era, pushing the calculus towards ENI

Yes. What significant toxicities would one significantly prevent by omitting ENI... LR recurrence of the tumor after HN XRT is a horrible toxicity in and of itself.

 

[Palex80]

Yes. What significant toxicities would one significantly prevent by omitting ENI... LR recurrence of the tumor after HN XRT is a horrible toxicity in and of itself.

Lymphedema?
The patient has had bilateral neck dissection with a high number of nodes dissected (thus I presume more or less all levels dissected). There is a considerable risk of turing his head into a baloon if you do bilateral ENI.

 

[2014XRT]

hope you have some really good data for sparing the necks in this case.

this isn't really a borderline case. treat the necks.

draw nice tiny volumes in 2-4 bilaterally, your PTV and 60 Gy isodose lines on top of that will take care of the rest, so makes sense to draw little cute CTVs in this case.

but by all means, treat the necks.

 

[2014XRT]

Lymphedema?
The patient has had bilateral neck dissection with a high number of nodes dissected (thus I presume more or less all levels dissected). There is a considerable risk of turing his head into a baloon if you do bilateral ENI.

yo, what?

considerably high risk?

for what's essentially a super standard treatment?

how much head and neck lymphedema are you guys seeing?

 

[seper]

40 nodes is not a particularly impressive neck cleanout. I’ve treated 2-3 patients with > 100


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[BobbyHeenan]

Thanks all for the excellent discussion.

I'm leaning toward just treating how I usually would (necks and operative site). I do think that the "data" we have for doing this way is just the way it's always been done and though that's not always the best reason to do something, there isn't much data that I'm aware of that says it's OK to omit ENI like we have in other disease sites (NSCLC, even SCLC now; really nothing strong to show pelvic nodal XRT for prostate is that helpful, etc). I really don't think his nodal recurrence rate is >10%, but a local recurrence is devastating, obviously.

Of note, in re reviewing RTOG 9501 they did allow dose of 54 Gy to areas of "low risk" - defined as "distant areas" away from the site that gave you an indication for post op treatment. So I think it's reasonable here to give 54 Gy to the ENI sites and 60 Gy to operative bed.

Morbidity here of ENI IMO is neck fibrosis, submental edema (not necessarily "balloon head" though that is possible), more dry mouth (though parotid sparing shouldn't be too much of an issue given no gross nodes).

 

[scarbrtj]

There is a considerable risk of turing his head into a baloon if you do bilateral ENI

Heh. Glad you didn't say "literally turning his head into a balloon..." I do a lot of postop HN XRT w/ENI, and spheroencephalopneumonitis complications are rare in my clinic; YMMV. And yes, the elective areas just need elective, subclinical doses (ie ~50 Gy range). Also, there is much data that the LR failure rate is >10% for T4N0 postop.

 

[BobbyHeenan]

Heh. Glad you didn't say "literally turning his head into a balloon..." I do a lot of postop HN XRT w/ENI, and spheroencephalopneumonitis complications are rare in my clinic; YMMV. And yes, the elective areas just need elective, subclinical doses (ie ~50 Gy range). Also, there is much data that the LR failure rate is >10% for T4N0 postop.
[/MEDIA]

To clarify, I meant the failure rate being <10% within ENI volume specifically. I think his failure rate in operative bed is >10%.

 

[Burt Radnolds]

I have treated a lot of head and neck cancer. I tend to use elective doses on the lower end of the spectrum and draw smallish CTVs right in the fat plane, omitting levels not at risk whenever possible. Submental edema is still a real problem in a not insignificant number of cases, and is unpredictable. It can be a major cosmetic issue for some patients and can also in severe cases cause mechanical issues related to swallowing and breathing. That said, I would still treat the necks here.

 

[evilbooyaa]

I can't think of a good scenario where I wouldn't treat the relevant necks in a T4N0 SCC of the head and neck. This one is no different. 54/30 is very reasonable level II-IV and all of VI given extent of primary.

Yes, there is risk of toxicity, but the greatest toxicity is recurrent disease. Palex, if your institution treats these without ENI, please publish the data so we can have some idea that it's not overtly dangerous to spare the necks.

 

[Palex80]

Palex, if your institution treats these without ENI, please publish the data so we can have some idea that it's not overtly dangerous to spare the necks.

Unfortunately these are rare cases which pop up only once or twice per year. But yes, we generally do not treat the neck in these cases. Incidental dose is another issue however. Large parts of level II, III receive dose if you only treat the larynx.

And last but not least not every pT4 is the same.

 

[scarbrtj]

To clarify, I meant the failure rate being <10% within ENI volume specifically.

Idk as the kids say. I feel like it's significantly higher for pT4N0 than 10% for a regional recurrence. If it is <10%, obviously the predominant practice of most radiation oncologists to do ENI here is... wrong-headed.

 

[Palex80]

Idk as the kids say. I feel like it's significantly higher for pT4N0 than 10% for a regional recurrence. If it is <10%, obviously the predominant practice of most radiation oncologists to do ENI here is... wrong-headed.

Are there any data to support either claim?

 

[scarbrtj]

Are there any data to support either claim?

Oh yes. Like this paper. It's truly a landmark in the field, ha. But most of the patients did have T4N0 it seems.

 

[BobbyHeenan]

Oh yes. Like this paper. It's tr

Truly a landmark in the field, ha. But most of the patients did have T4N0 it seems.

Just as good as anything else out there on this.

Thanks for the paper. Extrapolating from their local control curves, it looks like overall failure for N0 patients was about 23%. If you then remove the "local only" failures it looks like you'd have about a 13% rate of failure AFTER radiation.

So maybe your > 10% risk of out of field (if operative bed only covered) is correct.

Again - thanks for the discussion - I'm going to be treating comprehensively after reviewing plenty of literature.

As an FYI, the table in Gunderson for neck failure rate without radiation suggests lower than 10%, but these studies are incredibly heterogeneous and a squamous cell that busts through the laryngeal cartilage into the soft tissues of the neck probably doesn't behave like a p16 T2N0 tonsil....

 

[Palex80]

Oh yes. Like this paper. It's truly a landmark in the field, ha. But most of the patients did have T4N0 it seems.

I am sorry, but:

Surgery was the primary treatment modality in all the patients. Total laryngectomy without neck dissection was performed in 61 patients (79.2%). Total laryngectomy with unilateral or bilateral neck dissection was made only in patients with cytological proof of metastatic lymphadenopathy in the neck (16 patients, or 20.8%). Elective neck dissection was not realized in any patient.


This is a problem with this study. Neck dissection was not performed here as standard, which is kind of surprising.
So these are merely cN0-patients.
And like you already pointed out and referrenced, 40% of cN0-patients will end up to be pN+...

I don't think you can extrapolate from these date to make a point on the case we are discussing.

 

[mavrik13]

Less than 5% wouldn't be my metric. Here's why:
1) Pathological examinations are not as comprehensive as we think, and while this guy had a lot of LNs dissected, at the end of the day still only about 10-15% of his neck LNs have been sampled...
2) So the risk for (under-)sampling error might be high even with good dissections...
3) Especially given the fact that ~40% of cT4N0 laryngeal patients wind up having N+ disease at surgery...
4) And this guy had a tumor showing aggressive local behavior, which portends for a tumor that "knows" how to go to nodes too...
5) Plus, he had surgery; given likely microscopic local disease, who knows what kind of loop surgery throws re: screwing up the local lymphatics making a regional nodal risk higher post-surgery vs pre-surgery
6) Finally, how would you feel if you saw a patient back with a pT4N0 laryngeal who you'd given partial neck XRT of 60 Gy now with nodal, in- or edge-of-field recurrence? Me... I'd feel stupid.

Let pathological nodal bulk (±ECE) govern chemoRT/RT decisions, not ±ENI decisions.

What levels are you giving ENI to? Perhaps we have different definitions. Given a surgeon will dissect bilat 2-4 for a pT4N0 larynx, the operative bed includes bilat 2-4, therefore that area is being treated to 60/30. I wouldn't treat 1b, 5 or 6 in a node negative patient - which of those are you including in your ENI volume?

 

[Reaganite]

This issue was mentioned in ACR appropriateness guidelines for adjuvant XRT, but they didn't take a specific stance:

"The typical treatment volume used in PORT for head and neck cancer includes the bilateral neck as well as the surgically dissected primary tumor site. However, it is unclear whether both the neck and primary always need to be within the PORT volume. For patients with completely resected primary tumors whose sole indication for PORT is pathologic cervical adenopathy, some would direct therapy only to the neck. Additionally for patients with a positive margin as the sole indication for treatment in the setting of a comprehensive neck surgery, some would direct treatment to the primary resection bed only."

It's my understanding the adjuvant trials included bilateral neck regardless of nodal status. With a typical postop larynx field, you're including a lot of 2-4 just targeting the primary site operative bed; you're basically just omitting the posterior portion of 2-4. Does that limited nodal exclusion really cut back so substantially on morbidity that it's worth treating differently than the trials?

 

[2014XRT]

thanks for posting that reaganite.

i would point out that treating the primary site based on a margin issue is different than treating based on T4. the reason we are even treating the primary site in a R0 resected T4 is because something about the biology is nasty enough that we believe there must be microscopic disease there. The same thought process is true for the draining lymphatics. There is a strong indication in my mind to include that in your field. The nodes are at a reasonable enough risk compared to the primary. otherwise, just observe the whole case if you don't think there's microscopic disease there. I mean there are some disease sites we observe T4N0. Wouldnt you observe a pT4N0 lung nsclc that got upfront surgery and is getting adjuvant chemo? but i wouldn't personally observe a T4N0 larynx

With good VMAT planning that can get super conformal, unless you contour that nodal space and ask for coverage, you can't just bank on enough of it getting 54-56 (whatever you like your elective dose to be in this case)

the way to do it is draw nice tiny-ish contours but you need to draw something to get dose there.

 

[medgator]

thanks for posting that reaganite.

i would point out that treating the primary site based on a margin issue is different than treating based on T4. the reason we are even treating the primary site in a R0 resected T4 is because something about the biology is nasty enough that we believe there must be microscopic disease there. The same thought process is true for the draining lymphatics. There is a strong indication in my mind to include that in your field. The nodes are at a reasonable enough risk compared to the primary. otherwise, just observe the whole case if you don't think there's microscopic disease there. I mean there are some disease sites we observe T4N0. Wouldnt you observe a pT4N0 lung nsclc that got upfront surgery and is getting adjuvant chemo? but i wouldn't personally observe a T4N0 larynx

With good VMAT planning that can get super conformal, unless you contour that nodal space and ask for coverage, you can't just bank on enough of it getting 54-56 (whatever you like your elective dose to be in this case)

the way to do it is draw nice tiny-ish contours but you need to draw something to get dose there.

T4 lung cancers rarely go to surgery (by definition they're unresctable at that point). If someone was pT4 , I'm probably giving them post op xrt

 

[2014XRT]

guess it depends on the case and what made it T4 and how much you trust the surgeon.

but for what it's worth, the NCCN guidelines for resectable T4N0 does have surgery and then chemotherapy as the recommendation if there's an R0 resection.

 

[medgator]

guess it depends on the case and what made it T4 and how much you trust the surgeon.

but for what it's worth, the NCCN guidelines for resectable T4N0 does have surgery and then chemotherapy as the recommendation if there's an R0 resection.

I think it would be one of those situations where it was an incidental finding on the final path.

I doubt anyone is taking a cT4 pt to the OR

 

[Palex80]

T4 lung cancers rarely go to surgery (by definition they're unresctable at that point). If someone was pT4 , I'm probably giving them post op xrt

If however I was confronted with a pT4 pN0 NSCLC with a close marging in the lumg hilus, I would only treat the hilar region and not do ENI in order to treat the mediastinum... Even if the pT4 is "bad biology" it does not justify ENI in the context of pN0.
Why should it be different in head&neck?

 

[2014XRT]

1) the supraglottic larynx is ridiculously rich in lymphatics. Even a T2 has up to 40 percent nodal involvement.

2) you have a much better chance of curing the larynx patient with radiation, because of the much higher competing risk of distant failure in the lung patient

3) I ask again - why treat the larynx primary site (in setting of no margin issue) if you’re not going to treat the nodes when the risk of failure is nearly just as high there?

 

[Palex80]

1) the supraglottic larynx is ridiculously rich in lymphatics. Even a T2 has up to 40 percent nodal involvement.

So does a centrally located T2 NSCLC

2) you have a much better chance of curing the larynx patient with radiation, because of the much higher competing risk of distant failure in the lung patient

True.

3) I ask again - why treat the larynx primary site (in setting of no margin issue) if you’re not going to treat the nodes when the risk of failure is nearly just as high there?

I have yet to see any good data on patterns of failure for a pT4 pN0 laryngeal cancer. Can you point me out to some?

 

[evilbooyaa]

I am sorry, but:

Surgery was the primary treatment modality in all the patients. Total laryngectomy without neck dissection was performed in 61 patients (79.2%). Total laryngectomy with unilateral or bilateral neck dissection was made only in patients with cytological proof of metastatic lymphadenopathy in the neck (16 patients, or 20.8%). Elective neck dissection was not realized in any patient.


This is a problem with this study. Neck dissection was not performed here as standard, which is kind of surprising.
So these are merely cN0-patients.
And like you already pointed out and referrenced, 40% of cN0-patients will end up to be pN+...

I don't think you can extrapolate from these date to make a point on the case we are discussing.

Agree with Palex on the above points in regards to the posted article. We're trying to extrapolate data to fit our statements, rather than the other way around. Also, that trial used post-op RT and had a < 10% regional only recurrence rate (6/77 patients), but that doesn't mean anything since the question is what's the risk without RT.

I do think (without data) that the risk of regional recurrence is > 10% in a pT4N0 Laryngeal SCC w/o RT to the nodes. My last point in regards to this is that there isn't great data on this exact clinical scenario, but traditional wisdom is to cover the nodes in this situation (IMO, which may be controversial), and I would need more data to tell me that avoiding that was SAFE, rather than requiring data to prove the value of ENI. I can't find any recent patterns of recurrence papers for pT4N0 laryngeal SCC.

Risk of distant metastatic disease is IMO higher in pT4N0 NSCLC than T4N0 Laryngeal SCC. Even in the group from the previously posted paper that should be at high-risk for mets, 3/77 had metastatic disease, while 21/77 had locoregional recurrence.

Again, Palex, if your institution has routinely been omitting nodes for pT4N0, even a 20 patient series would get published, if you're so inclined.

 

[MDACCRules]

Not completely same situation, but here is T3N0M0 glottic cancer treated with RT to primary alone (which includes much of level III), and has no regional failure.

Seems like if you're very concerned about the toxicity of a larger field, then could consider treating tumor bed and all of level III bilaterally, which keeps you below the parotids.

But, I just don't get why get cute with this. Bilateral 2, 3, 4, and stay below parotids. Not that toxic, especially without chemotherapy.

 

[Palex80]

I believe that this is a gray zone. Perhaps not the gray zone as it is featured in the Red Journal, but a zone where our practice is guided by decades-long traditional treatment.
The problem is that noone can actually challenge this practice because evidence to change practice is minimal or non-existant.

To me it's a bit like the question of treatment volume in rectal cancer.
What is the optimal radiation field for a pT3 pN0 rectal cancer patient in the context of adjuvant RT?
Probably treating the mesorectum alone is sufficient. Perhaps treating only part of the mesorectum is ok too, like 2-3 cm craniocadually of the original tumor extension.
However many radiation oncologists would probably treat the regional nodes too (=pelvis). Why? Because data on treating only the mesorectum is scarce and in all the big trials on adjuvant RT for rectal cancer the treatment volume included regional nodes too.

 

[scarbrtj]

To me it's a bit like the question of treatment volume in rectal cancer.

You can take this argument to many disease sites. Today, I Rx'd whole breast RT for a postop T1NO breast cancer. There's more data for local breast tumor cavity only RT vs whole breast (a lot of data) than there is for local RT only for T4N0 laryngeal (almost no data it's safe or bad) vs "standard" local+neck ENI, correct? So if you're doing any whole breast RT in low risk breast cancer, but only doing local RT only for pT4N0 laryngeal... that's interesting

 

[Radonc90]

OLD thread but my question is NOT about volume but specifically about "subclinical dose".
- Years ago, Fletcher et al established that 44 Gy is "good enough" for subclinical neck.
- The 44 Gy in 22 fx was widely used in the RTOG HN trials (+/- CDDP etc.) in the 1990s.

- More recently (maybe the last 10-12 yrs), ever since IMRT came out and the concept of SIB kicked in, somehow someone writing the RTOG HN protocols decided for "subclinical neck":
1. They reduced the fractional dose to 140-150 cGy but
2. They increased total dose to 56 Gy.

I understand they used alpha/beta equation and all that jazz to arrive at 56 Gy but why???
Why can't they keep "subclinical dose" at 44 Gy in 22 fx?

Maybe they want one single plan with SIB and the entire Tx is completed within ____ days???

Can some smart radonc's make some comments?

 

[Ray D. Ayshun]

OLD thread but my question is NOT about volume but specifically about "subclinical dose".
- Years ago, Fletcher et al established that 44 Gy is "good enough" for subclinical neck.
- The 44 Gy in 22 fx was widely used in the RTOG HN trials (+/- CDDP etc.) in the 1990s.

- More recently (maybe the last 10-12 yrs), ever since IMRT came out and the concept of SIB kicked in, somehow someone writing the RTOG HN protocols decided for "subclinical neck":
1. They reduced the fractional dose to 140-150 cGy but
2. They increased total dose to 56 Gy.

I understand they used alpha/beta equation and all that jazz to arrive at 56 Gy but why???
Why can't they keep "subclinical dose" at 44 Gy in 22 fx?

Maybe they want one single plan with SIB and the entire Tx is completed within ____ days???

Can some smart radonc's make some comments?

I'm not a smart radonc, but I do 44 Gy for elective volumes only with chemo. 50 Gy without, which is perhaps more equivalent. I'm not into sibs for intact H&N.

 

[seper]

the original concept had surgically violated neck, which requires more dose -- true

 

[Radonc90]

I am talking about Clinical N0 neck (the "subclinical neck" in Fletcher's term), un-dissected neck.

 

[gmsquid]

re the neck question: with a pT4N0 tumor there is still significant risk to the upper mediadtinal nodes particularly with anterior extension. I will always treat nodes. I’ve seen tracheoesophageal node failures and they are terrible. These are bad tumors and tissue planes in the neck are violated by the surgical dissection. There is substantial risk of microscopic disease in the dissected neck. Plus you need at least 57.6 in 1.8 Gy to the dissected tissue due to hypoxia according to Peters et al. Plus, I don’t think the morbidity spared in avoiding treating levels 3 and 4 is significant. Treating 2 does add more parotid morbidity and oral cavity low dose with imrt though with a good plan you can reduce those doses pretty substantially., though you don’t have to cover retrostyloids or RPs which add much more morbidity.

T3N0 glottis is a different situation but it also depends on what makes the tumor T3. That paper is T3 without vocal cord fixation which is very select disease with minimal supraglottic, subglottic extent and Parag logic extent to have access to lymphatics.

Regarding the elective dose question, Dosimetrically SIBs are better plans. You can’t keep plans as tight with sequential boosts which minimizes your feasibility in sparing certain structures near or even at a modest distance from gross tumor even though the dose may be lower in certain elective areas. I universally do SIB

 

[Radonc90]

I am not against SIB, I use it often.
The question is: can one use SIB but keep the dose of the cN0 (un-dissected neck) at the lower level such as 44 Gy at 2 Gy/fx?

 

[scarbrtj]

OLD thread but my question is NOT about volume but specifically about "subclinical dose".
- Years ago, Fletcher et al established that 44 Gy is "good enough" for subclinical neck.
- The 44 Gy in 22 fx was widely used in the RTOG HN trials (+/- CDDP etc.) in the 1990s.

- More recently (maybe the last 10-12 yrs), ever since IMRT came out and the concept of SIB kicked in, somehow someone writing the RTOG HN protocols decided for "subclinical neck":
1. They reduced the fractional dose to 140-150 cGy but
2. They increased total dose to 56 Gy.

I understand they used alpha/beta equation and all that jazz to arrive at 56 Gy but why???
Why can't they keep "subclinical dose" at 44 Gy in 22 fx?

Maybe they want one single plan with SIB and the entire Tx is completed within ____ days???

Can some smart radonc's make some comments?

In the early days of IMRT when trilobites swam the seas, a two-plan IMRT was essentially impossible. (Lots of reasons for that.) So SIB wasn't a neat new concept; necessity was the mother of that invention. At the first center in the country to be doing routine linac-based IMRT for HNSCC it was felt that sub-1.8 Gy doses, anywhere, would be "bad," so first what was tried was 30 fraction plans. And the lowest-tier dose was 54/30. And the GTV was Rx'd 72 Gy/30 fx. People got hurt. The docs went "woops" .... let's drop back to 70/35. So if you felt like you **must** devise a plan where the tumor gets the traditional 70 Gy in 35 fractions, this means you're locked in to 35 fractions... for everything. So what will be the lowest Rx dose at 35 fractions you'd like to see? It was chosen to be 56 Gy to low-risk subclinical at 1.6 a day and 1.8 a day (63 Gy) to "high risk" subclinical. Quite empirically. There was in actuality less alpha/beta in this than a decision to go with the nice round numbers of 1.6/1.8/2.0 a day. There was *zero* data that 1.6 a day was OK in HNSCC when it was chosen to be used. Fortunately, it turned out OK I guess.

 

[RadOncMegatron]

I am not against SIB, I use it often.
The question is: can one use SIB but keep the dose of the cN0 (un-dissected neck) at the lower level such as 44 Gy at 2 Gy/fx?

I agree here. I was trained on SIB, but never liked the 56 Gy using 1.6 or 54.12 via 1.64. I find myself boosting a lot more these days Definitely times where 44 Gy followed by a BV beats SIB. This is usually for small volume disease.

 

[Ray D. Ayshun]

Though not really applicable to post-op h&n, I don't do sibs if I think there's a good chance I'll have to replan. Just a thing with me I guess.

 

[evilbooyaa]

OLD thread but my question is NOT about volume but specifically about "subclinical dose".
- Years ago, Fletcher et al established that 44 Gy is "good enough" for subclinical neck.
- The 44 Gy in 22 fx was widely used in the RTOG HN trials (+/- CDDP etc.) in the 1990s.

- More recently (maybe the last 10-12 yrs), ever since IMRT came out and the concept of SIB kicked in, somehow someone writing the RTOG HN protocols decided for "subclinical neck":
1. They reduced the fractional dose to 140-150 cGy but
2. They increased total dose to 56 Gy.

I understand they used alpha/beta equation and all that jazz to arrive at 56 Gy but why???
Why can't they keep "subclinical dose" at 44 Gy in 22 fx?

Maybe they want one single plan with SIB and the entire Tx is completed within ____ days???

Can some smart radonc's make some comments?

Interesting point. I have not routinely seen 44/22 for RTOG trials. I know a fair number of people were doing 50/25 for lower neck (like MSKCC (I think?) for SCV fields junctioned to an IMRT plan for above), so I figured 56/35 was just an extrapolation of 50/25.

One could, theoretically, do 22 fx - lowest risk gets 44Gy, then boost. Where I trained SIB was all the rage - where I currently practice doing two plans is much more commonplace. I was scared by the boogie man of homogeneity but I've seen pretty nice plans (maybe a little cold for the boost) with a 2-plan technique. I think doing original plan + boost + boost is where homogeneity really has to get sacrificed.

 

[Radonc90]

The 44Gy/22fx for "subclinical neck" is very old stuff, going back to Fletcher's, Ang's days...

In the RTOG 1016 (The Cetuximab thingy), the 44Gy/22fx idea is there:

https://clinicaltrials.gov/ProvidedDocs/34/NCT01302834/Prot_SAP_001.pdf

Anyway, I think 56Gy (lower daily fractional dose) is overkill, just my 2 pennies.

 

[gmsquid]

The 44Gy/22fx for "subclinical neck" is very old stuff, going back to Fletcher's, Ang's days...

In the RTOG 1016 (The Cetuximab thingy), the 44Gy/22fx idea is there:

https://clinicaltrials.gov/ProvidedDocs/34/NCT01302834/Prot_SAP_001.pdf

Anyway, I think 56Gy (lower daily fractional dose) is overkill, just my 2 pennies.

Well trials are dropping that dose. 5250 in 35 is the elective dose on HN005 to low echelon nodes albeit in the p16 positive population.

there is a randomized trial trying to argue that 40 Gy in 2 Gy elective may be sufficient though regional nodal failures were higher in the lower dose arm (but not in elective areas): Randomized clinical trial on reduction of radiotherapy dose to the elective neck in head and neck squamous cell carcinoma; update of the long-term tumor outcome - PubMed

 

[scarbrtj]

Well trials are dropping that dose. 5250 in 35 is the elective dose on HN005 to low echelon nodes albeit in the p16 positive population.

there is a randomized trial trying to argue that 40 Gy in 2 Gy elective may be sufficient though regional nodal failures were higher in the lower dose arm (but not in elective areas):

How about 30 Gy... 0% Gr3 or greater(!) toxicity rate. Regardless, 56/35 to elective areas is tougher on patients IMHO versus 50/25 (or 40/20), either of which can only be rationally achieved by staging (ie "two-scan planning," or more) the dosing.