FLAME TRIAL prostate boost - ?lymph nodes?

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SneakyBooger said:
POP-RT inclusion was >20% LN risk per Roach formula (median est. risk was 37.8%).

Median PSA 28.

Gleason Group 4-5 = 49%.

DFS benefit not seen for those >66YO and LN risk <40%.

DMFS benefit (unplanned subgroup analysis) not seen in >66YO.

Thanks for the article. Lots of ideas in there. I'm digging through it now. Do you have the supplement? I love supplements. A lot of good stuff is often hidden in the supplements. Maybe I missed it at the link you gave.

We each can have different take homes from that study.

Totally agree, no wrong answer. For me, I suspect the differences seen in regards to bDFS and MFS is more likely due to this: "the use of adjuvant ADT was not standardized for these patients, with a substantial difference in use of adjuvant ADT between both treatment groups (SBRT: 23% vs. ENRT: 60%)."
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Relevant: acute GU/GI toxicity appear to be similar from early results of PEACE V STORM

 
evilbooyaa said:
Relevant: acute GU/GI toxicity appear to be similar from early results of PEACE V STORM

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Thanks for the timely link regarding acute toxicities.

I would have thought there would more than 196 pts in this trial. Only 7 pts had grade 2+ toxicity.

It's paywalled, but here is part of the abstract. As always, looking forward to digesting this. (But that will have to wait as I am on a different mission this morning.)

Results and limitations​

Between June 2018 and April 2021, 196 patients were assigned randomly to MDT or ENRT. Ninety-seven of 99 patients allocated to MDT and 93 of 97 allocated to ENRT received per-protocol treatment. Worst acute GI toxicity proportions were as follows: grade ≥2 events in three (3%) in the MDT group versus four (4%) in the ENRT group (p = 0.11). Worst acute GU toxicity proportions were as follows: grade ≥2 events in eight (8%) in the MDT group versus 12 (13%) in the ENRT group (p = 0.95). We observed no significant difference between the study groups in the proportion of patients with a clinically significant QoL reduction from baseline for any subdomain score area.
 
SneakyBooger said:
Thanks for the timely link regarding acute toxicities.

I would have thought there would more than 196 pts in this trial. Only 7 pts had grade 2+ toxicity.

It's paywalled, but here is part of the abstract. As always, looking forward to digesting this. (But that will have to wait as I am on a different mission this morning.)

Results and limitations​

Between June 2018 and April 2021, 196 patients were assigned randomly to MDT or ENRT. Ninety-seven of 99 patients allocated to MDT and 93 of 97 allocated to ENRT received per-protocol treatment. Worst acute GI toxicity proportions were as follows: grade ≥2 events in three (3%) in the MDT group versus four (4%) in the ENRT group (p = 0.11). Worst acute GU toxicity proportions were as follows: grade ≥2 events in eight (8%) in the MDT group versus 12 (13%) in the ENRT group (p = 0.95). We observed no significant difference between the study groups in the proportion of patients with a clinically significant QoL reduction from baseline for any subdomain score area.
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Another example of overutilization of p-values. In small studies like this the authors should emphasize CI of HR. I expect they are very wide and probably cannot conclude much of anything. If p>0.05 please provide CI of HR
 
BobbyHeenan said:
I know on the FLAME trial they did not cover lymph nodes electively.

I have had good outcomes with mostly unfav int risk patients that I've treated per the flame regimen (35 fractions). I've tried to keep my treatment as close to protocol parameters as possible. I really like it for patients that fit enrollment criteria and there is a well definted boost target with congruent biopsy findings.

I have a guy now that is a great candidate for this - very well delineated MRI target, congruent location on biopsy, even his PSMA is focally hot here and no where else in prostate. He has G9 disease but no lymph node mets on PSMA. PSA single digits.

I often cover lymph nodes for high risk non FLAME cases. Usually I do 70 Gy prostate and 50.4 nodes here in 28 fractions. POP-RT says maybe this is helpful.

I have contemplated something like 1.6 Gy (56 Gy) to nodes, 77 Gy to Prostate PTV, then the intraprostatic boost....but it doesn't set right with me.

I have been doing some FLAME-like cases at 70/28 to prostate and then like 80ish to the boost. I guess I could treat nodes 50.4 Gy in that situation.

Any thoughts here? I think I may just stick to no elective XRT here...with a VERY hot PSMA scan in the prostate focal lesion (SUV > 40) I feel like maybe no nodes are truly involved now.
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FWIW (now three years later) I have settled on 52.5 Gy in 35 Fx (1.5 Gy/Fx) for these cases. I am most comfortable using the exact dose and fractionation that the original FLAME trial used for the prostate/boost, and the EQD2 of 52.5 Gy/35 Fx is in the ballpark of what I would use in other elective nodal situations.

Regarding the 1.5 Gy/Fx, RTOG 0529 used 1.5 Gy/Fx for elective nodal treatment, so there is a precedent for that fraction size in the pelvis (though that was of course an anal cancer trial).
 
Medapp14 said:
FWIW (now three years later) I have settled on 52.5 Gy in 35 Fx (1.5 Gy/Fx) for these cases. I am most comfortable using the exact dose and fractionation that the original FLAME trial used for the prostate/boost, and the EQD2 of 52.5 Gy/35 Fx is in the ballpark of what I would use in other elective nodal situations.

Regarding the 1.5 Gy/Fx, RTOG 0529 used 1.5 Gy/Fx for elective nodal treatment, so there is a precedent for that fraction size in the pelvis (though that was of course an anal cancer trial).
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Maybe I’m missing the “problem,” but what is with our occasional compulsion to awkwardly shoehorn weird daily fraction sizes into a regimen based on its fraction number. Why not make two plans, one flaming the prostate and the other treating nodes 50/25, and then that one is done and it’s 10 prostate flames in plan 2.
 
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TheWallnerus said:
Maybe I’m missing the “problem,” but what is with our occasional compulsion to awkwardly shoehorn weird daily fraction sizes into a regimen based on its fraction number. Why not make two plans, one flaming the prostate and the other treating nodes 50/25, and then that one is done and it’s 10 prostate flames in plan 2.
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Thats what I do.
 
TheWallnerus said:
Maybe I’m missing the “problem,” but what is with our occasional compulsion to awkwardly shoehorn weird daily fraction sizes into a regimen based on its fraction number. Why not make two plans, one flaming the prostate and the other treating nodes 50/25, and then that one is done and it’s 10 prostate flames in plan 2.
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ramsesthenice said:
Thats what I do.
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I will start doing this.

Though I’ve been doing Flame-ish 28 fractions - 70 to prostate, DIL boost, 50.4 to nodes) fraction regimens but I think what you’re saying here is more true to the trial where it matters most - in the prostate.
 
BobbyHeenan said:
I will start doing this.

Though I’ve been doing Flame-ish 28 fractions - 70 to prostate, DIL boost, 50.4 to nodes) fraction regimens but I think what you’re saying here is more true to the trial where it matters most - in the prostate.
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Oh, I should clarify...this is my preference. But Evicore has shut down 35 fractions for intact prostate even when boosting and I still do a lot of what you describe. I take the nodes to 45 and the prostate to 62.5 in the first 25 fx and then do a 3 fx boost. Take the DIL to around 85 total. It seems to work just as well but it felt a little more "made up" to me and was not my preference.
 
TheWallnerus said:
I’m not being churlish or sarcastic but isn’t it wild that every radiation oncologist irradiates the prostate slightly differently but patient outcomes are so homogenous.
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Which patient outcomes?

MIRAGE studied a common variation (PTV size) rigorously and found a difference in patient outcomes.
 
Neuronix said:
Which patient outcomes?

MIRAGE studied a common variation (PTV size) rigorously and found a difference in patient outcomes.
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That’s true! I don’t really see differences anecdotally or with my own eyes but we have the MIRAGE.

I recant. Even slight irradiation technique variances yield different patient outcomes. So patient outcomes must be highly variable across the US because rad oncs all irradiate the prostate variably.
 
TheWallnerus said:
That’s true! I don’t really see differences anecdotally or with my own eyes but we have the MIRAGE.

I recant. Even slight irradiation technique variances yield different patient outcomes. So patient outcomes must be highly variable across the US because rad oncs all irradiate the prostate variably.
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G2 toxicities very well may be. I don’t think they’re well recorded or reported.
 
Medapp14 said:
FWIW (now three years later) I have settled on 52.5 Gy in 35 Fx (1.5 Gy/Fx) for these cases. I am most comfortable using the exact dose and fractionation that the original FLAME trial used for the prostate/boost, and the EQD2 of 52.5 Gy/35 Fx is in the ballpark of what I would use in other elective nodal situations.

Regarding the 1.5 Gy/Fx, RTOG 0529 used 1.5 Gy/Fx for elective nodal treatment, so there is a precedent for that fraction size in the pelvis (though that was of course an anal cancer trial).
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This is one of the silliest things I've heard. Low dose/Fx for prostate cancer? Why? RTOG 0529 was for anal cancer. Anal SCC. Different radiosensitivity than prostate cancer.

Lots of ways to skin the cat. This is one of the silliest ones I've heard.

For 28Fx mine is 70to Primary, 50.4 to nodes, 56 to entire SV (if indicated) 84 to GTV all in 1 plan.

For 44Fx 79.2 to primary, 45 to nodes (in 25), 54 to entire SV (if indicated, in 30), 101.2 to GTV, in 2-3 plans.
 
who are the patients that people still doing ENI for?
 
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Curious to those doing microboost with 28 or 45 fx - why not just use 35 since we have data for it and it works and is isotoxic? Is it just b/c 35 is "weird"?
 
WildRivers said:
Curious to those doing microboost with 28 or 45 fx - why not just use 35 since we have data for it and it works and is isotoxic? Is it just b/c 35 is "weird"?
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I imagine sometimes insurance doesn’t allow 35 instead of 28, easier to just give 28. That said insurance companies have no problem at all with a doctor giving more fractions than are allowed… for free.

And when fraction number is not prior auth’d 45 vs 35 is profit margin, the other important margin in rad onc.
 
FLAME is on NCCN; have not had issue with authorization. See footnote b.

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RadOncMegatron said:
What are people thoughts on DELINEATE? 67/60 in 20 fractions.
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I have been doing 60 Gy with SIB to 68 to dominant nodule for about 3-5 years and it seems well tolerated. I allow coverage of GTV to be lower if within proximity of urethra/rectum/bladder. I started doing it on trial with the NRG studies and was happy with the results.
 
salubalu said:
I have been doing 60 Gy with SIB to 68 to dominant nodule for about 3-5 years and it seems well tolerated. I allow coverage of GTV to be lower if within proximity of urethra/rectum/bladder. I started doing it on trial with the NRG studies and was happy with the results.
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I have used this pretty much the same and have good results. I have been getting fiducials and spacers just to be extra paranoid.
 
WildRivers said:
Curious to those doing microboost with 28 or 45 fx - why not just use 35 since we have data for it and it works and is isotoxic? Is it just b/c 35 is "weird"?
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Because I don't know how to counsel patients on the general toxicities of radiation with a 35Fx regimen (ignoring the microboost bit).

conventional (44 for me) vs mod hypo (20-28) I have lots of good data. If not treating nodes, 44 has lower acute GI but otherwise similar. If treating LNs , 44 has lower late GI per pHART2 trial.

I don't know what the toxicity profile of 35 is, and thus I am loathe to let the FLAME microboost define my # of fx for the rest of the prostate.
 
evilbooyaa said:
Because I don't know how to counsel patients on the general toxicities of radiation with a 35Fx regimen (ignoring the microboost bit).

conventional (44 for me) vs mod hypo (20-28) I have lots of good data. If not treating nodes, 44 has lower acute GI but otherwise similar. If treating LNs , 44 has lower late GI per pHART2 trial.

I don't know what the toxicity profile of 35 is, and thus I am loathe to let the FLAME microboost define my # of fx for the rest of the prostate.
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Just read the paper 🙂 All the data is there.

If you look at the study, the GU toxicity looks worse in FLAME study as compared to some of our 70 in 28 studies. 40% vs 20%. Discrepancy is probably b/c of the way the Dutch proactively prescribe Flomax at a lower threshold than we do. "Dutch Effect" - this was seen in HYPRO (60%!), as well. This is discussed in the literature.

It's a bit hotter, 7% or so. But, I suspect the patients do about as well as they do with 70/28. If you look at CHIP (not Dutch, but also across pond), they had 50% gr2 acute urinary toxicity, as well. GI was same. The 77 Gy < 1cc constraint is tight!

It's well tolerated. Patients do very well, at least in my experience. With the dose being so high, I've not wanted to experiment off study. But, I guess what you're saying makes sense - the devil you know.

Here is acute urinary toxicity from representative studies:

1776193869175.png
 
WildRivers said:
If you look at the study, the GU toxicity looks worse in FLAME study as compared to some of our 70 in 28 studies. 40% vs 20%. Discrepancy is probably b/c of the way the Dutch proactively prescribe Flomax at a lower threshold than we do. "Dutch Effect" - this was seen in HYPRO (60%!), as well. This is discussed in the literature.
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This has been looked into and comes from hotspots at the bladder neck and mainly the urethra.
There is a secondary analysis of FLAME showing that when the microboost is placed near the urethra and no constraint is defined for the urethra (there was no constraint in the protocol), toxicity goes up, pretty fast.
pubmed.ncbi.nlm.nih.gov

Urethral and bladder dose-effect relations for late genitourinary toxicity following external beam radiotherapy for prostate cancer in the FLAME trial - PubMed

Further increasing the dose to the bladder and urethra will result in a significant increase in GU toxicity following EBRT. Focal boost treatment plans should incorporate a urethral dose-constraint. Further treatment optimization to increase the focal boost dose without increasing the dose to...
pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov
Very elegantly shown here.
1776201038234.png

The solution is simple: Define the urethra and set a constraint, avoiding hotspots to it. If you want to be even more safe, add a PRV.

The DELINEATE trial, microboosting in 20fx, defined a constraint for the urethra.
 
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Palex80 said:
This has been looked into and comes from hotspots at the bladder neck and mainly the urethra.
There is a secondary analysis of FLAME showing that when the microboost is placed near the urethra and no constraint is defined for the urethra (there was no constraint in the protocol), toxicity goes up, pretty fast.
pubmed.ncbi.nlm.nih.gov

Urethral and bladder dose-effect relations for late genitourinary toxicity following external beam radiotherapy for prostate cancer in the FLAME trial - PubMed

Further increasing the dose to the bladder and urethra will result in a significant increase in GU toxicity following EBRT. Focal boost treatment plans should incorporate a urethral dose-constraint. Further treatment optimization to increase the focal boost dose without increasing the dose to...
pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov
Very elegantly shown here.
View attachment 417821
The solution is simple: Define the urethra and set a constraint, avoiding hotspots to it. If you want to be even more safe, add a PRV.

The DELINEATE trial, microboosting in 20fx, defined a constraint for the urethra.
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It’s crazy not to define and constrain the urethra. I do exactly what you suggested. If I can’t see the urethra well on their pre-sim MRI, I put a foley in for sim. Then do a PRV by contouring urethra avoid as an 8 mm circle centered on the urethra on axial imaging. It’s conservative but almost never compromises GTV coverage. I’ve seen absolutely no perceptible changes in toxicity when doing flame boosting this way.
 
ramsesthenice said:
It’s crazy not to define and constrain the urethra. I do exactly what you suggested. If I can’t see the urethra well on their pre-sim MRI, I put a foley in for sim. Then do a PRV by contouring urethra avoid as an 8 mm circle centered on the urethra on axial imaging. It’s conservative but almost never compromises GTV coverage. I’ve seen absolutely no perceptible changes in toxicity when doing flame boosting this way.
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Do you sim the patients with an MRI with a Foley in as well? How do you define your GTV with a Foley in place? Won't there be deformation of the gland compared to the pre-sim MRI?
 
WildRivers said:
Just read the paper 🙂 All the data is there.

If you look at the study, the GU toxicity looks worse in FLAME study as compared to some of our 70 in 28 studies. 40% vs 20%. Discrepancy is probably b/c of the way the Dutch proactively prescribe Flomax at a lower threshold than we do. "Dutch Effect" - this was seen in HYPRO (60%!), as well. This is discussed in the literature.

It's a bit hotter, 7% or so. But, I suspect the patients do about as well as they do with 70/28. If you look at CHIP (not Dutch, but also across pond), they had 50% gr2 acute urinary toxicity, as well. GI was same. The 77 Gy < 1cc constraint is tight!

It's well tolerated. Patients do very well, at least in my experience. With the dose being so high, I've not wanted to experiment off study. But, I guess what you're saying makes sense - the devil you know.

Here is acute urinary toxicity from representative studies:

View attachment 417809
Click to expand...

I prefer 70/28 if I'm doing mod hypo and thus put my patients at a numerically lower risk of acute GU toxicity than either FLAME arm WHILE also delivering 7 less treatments of radiation. Double Winning!

Palex80 said:
This has been looked into and comes from hotspots at the bladder neck and mainly the urethra.
There is a secondary analysis of FLAME showing that when the microboost is placed near the urethra and no constraint is defined for the urethra (there was no constraint in the protocol), toxicity goes up, pretty fast.
pubmed.ncbi.nlm.nih.gov

Urethral and bladder dose-effect relations for late genitourinary toxicity following external beam radiotherapy for prostate cancer in the FLAME trial - PubMed

Further increasing the dose to the bladder and urethra will result in a significant increase in GU toxicity following EBRT. Focal boost treatment plans should incorporate a urethral dose-constraint. Further treatment optimization to increase the focal boost dose without increasing the dose to...
pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov
Very elegantly shown here.
View attachment 417821
The solution is simple: Define the urethra and set a constraint, avoiding hotspots to it. If you want to be even more safe, add a PRV.

The DELINEATE trial, microboosting in 20fx, defined a constraint for the urethra.
Click to expand...
Can't blame the microboost int he arm that didn't get the microboost....

And yes, I constraint urethra regardless of the non-FLAME regimen I do.

Ya'll do what you like, let me do what I like.

A lot of patients are getting ENI now even with FLAME boosts. FLAME didn't allow ENI at all. We all thought mod hypo with ENI would be similar outcomes to mod hypo without ENI.... until an actual randomized trial came out showing G3 late GI toxicity of ~10%, higher than conventional RT... Randomized Trial of Concomitant Hypofractionated Intensity Modulated Radiation Therapy Boost Versus Conventionally Fractionated Intensity Modulated Radiation Therapy Boost for Localized High-Risk Prostate Cancer (pHART2-RCT) - PubMed
 
evilbooyaa said:
I prefer 70/28 if I'm doing mod hypo and thus put my patients at a numerically lower risk of acute GU toxicity than either FLAME arm WHILE also delivering 7 less treatments of radiation. Double Winning!


Can't blame the microboost int he arm that didn't get the microboost....

And yes, I constraint urethra regardless of the non-FLAME regimen I do.

Ya'll do what you like, let me do what I like.

A lot of patients are getting ENI now even with FLAME boosts. FLAME didn't allow ENI at all. We all thought mod hypo with ENI would be similar outcomes to mod hypo without ENI.... until an actual randomized trial came out showing G3 late GI toxicity of ~10%, higher than conventional RT... Randomized Trial of Concomitant Hypofractionated Intensity Modulated Radiation Therapy Boost Versus Conventionally Fractionated Intensity Modulated Radiation Therapy Boost for Localized High-Risk Prostate Cancer (pHART2-RCT) - PubMed
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Did not know about that study about the nodal SIB. Just goes to show that SIBs have been picked up for every site without any sort of data or concern that it may not be as good as SEQ. I've reverted back to SEQ for head/neck and anal; I find they tolerate treatment better. I had a long conversation with Gemini about this 🙂 I think this is the sort of practical trial that only a place like TATA could do, but I bet in at least a few sites SIB would be worse than SEQ.
 
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WildRivers said:
Did not know about that study about the nodal SIB. Just goes to show that SIBs have been picked up for every site without any sort of data or concern that it may not be as good as SEQ. I've reverted back to SEQ for head/neck and anal; I find they tolerate treatment better. I had a long conversation with Gemini about this 🙂 I think this is the sort of practical trial that only a place like TATA could do, but I bet in at least a few sites SIB would be worse than SEQ.
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In today’s reimbursement landscape, versus sequential … what does SIB stand for? Shriveled Income Blueprint?
 
WildRivers said:
pubmed.ncbi.nlm.nih.gov

A prospective randomized study of sequential boost versus simultaneous integrated boost intensity-modulated radiation therapy with concurrent chemotherapy in locally advanced head and neck cancer - PubMed

Reduced overall treatment time and convenience in RT planning are significant advantages of SIB, especially in high-volume centers. Anticipation of higher grades of dysphagia and management of the same is necessary.
pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov
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That's a wild conclusion.

SIB-IMRT showed a higher grade 3 or more dysphagia (45.5% vs. 24.2%, P 0.001) and higher nasogastric tube dependency.
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But, don't let 21% higher grade 3 tox get in the way of your high volume efficiency. 🤯🤯

Conclusion: Reduced overall treatment time and convenience in RT planning are significant advantages of SIB, especially in high-volume centers. Anticipation of higher grades of dysphagia and management of the same is necessary.
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Another head neck RCT - A randomized prospective study comparing acute toxicity, compliance and objective response rate between simultaneous integrated boost and sequential intensity-modulated radiotherapy for locally advanced head and neck cancer

Not randomized, but anal cancer study showed skin better, but worse fecal incontinence with SIB - Comparative analysis of toxicity in patients with anal cancer undergoing definitive simultaneous integrated boost (SIB) or sequential integrated boost (SeqB) radiotherapy - PMC .. odd how they phrased the conclusion, though. 22% vs 10% fecal incontinence is a big deal

There's a few other, I'll likely write a post about this. Thesis - "SIBs are good for physicists and administrators focused on conformality and efficiency, while SEQ is better for biologic recovery and relevant adverse effects"
 
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WildRivers said:
Another head neck RCT - A randomized prospective study comparing acute toxicity, compliance and objective response rate between simultaneous integrated boost and sequential intensity-modulated radiotherapy for locally advanced head and neck cancer

Not randomized, but anal cancer study showed skin better, but worse fecal incontinence with SIB - Comparative analysis of toxicity in patients with anal cancer undergoing definitive simultaneous integrated boost (SIB) or sequential integrated boost (SeqB) radiotherapy - PMC .. odd how they phrased the conclusion, though. 22% vs 10% fecal incontinence is a big deal

There's a few other, I'll likely write a post about this. Thesis - "SIBs are good for physicists and administrators focused on conformality and efficiency, while SEQ is better for biologic recovery and relevant adverse effects"
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Paper is terribly written so its hard to tell but it seems like this is really a comparison of 3D Seq B versus IMRT SIB.

Another banger from the Italians 🙂

1776778232245.png
 
Sure, some of the data is 3D vs IMRT instead of pure IMRT vs IMRT, but many of the papers are true IMRT vs IMRT comparisons.

Point is, why did we change without having data and why do the studies now if we decided already that SIB is better? I'm not a scientist, but this seems like kind of a bad way to do science.
 
WildRivers said:
Sure, some of the data is 3D vs IMRT instead of pure IMRT vs IMRT, but many of the papers are true IMRT vs IMRT comparisons.

Point is, why did we change without having data and why do the studies now if we decided already that SIB is better? I'm not a scientist, but this seems like kind of a bad way to do science.
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We changed to sib because at the time imrt computation was very resource intensive and took so much more effort and skill than today. Ultimately we need to really limit elective volumes and doses to begin with. 30gy sequential is a great start in head and neck.
 
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RickyScott said:
We changed to sib because at the time imrt computation was very resource intensive and took so much more effort and skill than today. Ultimately we need to really limit elective volumes and doses to begin with. 30gy sequential is a great start in head and neck.
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I don't know if that's a primary reason. IMRT came out in '94-'95. Every thing was sequential for nearly a decade. The treatment planning software improved considerably over the course of a decade and SIB wasn't published about until 2003ish. It didn't become mainstream for head neck until well past 2010. I am sure certain practices used it, but the first decade was almost entirely sequential and then around 2008ish SIB picked up and became dominant.

I guess maybe if the utilization overall rose quicker than the tx planning software, perhaps in late 2000s or early 2010s, since SIB was a capability, they transitioned to do it to improve throughput. But, no one was pushing me ever to do SIB at any point or seemed annoyed when not doing SIB.
 
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WildRivers said:
I don't know if that's a primary reason. IMRT came out in '94-'95. Every thing was sequential for nearly a decade. The treatment planning software improved considerably over the course of a decade and SIB wasn't published about until 2003ish. It didn't become mainstream for head neck until well past 2010. I am sure certain practices used it, but the first decade was almost entirely sequential and then around 2008ish SIB picked up and became dominant.

I guess maybe if the utilization overall rose quicker than the tx planning software, perhaps in late 2000s or early 2010s, since SIB was a capability, they transitioned to do it to improve throughput. But, no one was pushing me ever to do SIB at any point or seemed annoyed when not doing SIB.
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SIB seems problematic when the boost volume changes so much a la p16+ head and neck cancer. Maybe less of a big deal in anal given prescription dose.
 
RickyScott said:
We changed to sib because at the time imrt computation was very resource intensive and took so much more effort and skill than today. Ultimately we need to really limit elective volumes and doses to begin with. 30gy sequential is a great start in head and neck.
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WildRivers said:
I don't know if that's a primary reason. IMRT came out in '94-'95. Every thing was sequential for nearly a decade. The treatment planning software improved considerably over the course of a decade and SIB wasn't published about until 2003ish. It didn't become mainstream for head neck until well past 2010. I am sure certain practices used it, but the first decade was almost entirely sequential and then around 2008ish SIB picked up and became dominant.

I guess maybe if the utilization overall rose quicker than the tx planning software, perhaps in late 2000s or early 2010s, since SIB was a capability, they transitioned to do it to improve throughput. But, no one was pushing me ever to do SIB at any point or seemed annoyed when not doing SIB.
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Ray D. Ayshun said:
SIB seems problematic when the boost volume changes so much a la p16+ head and neck cancer. Maybe less of a big deal in anal given prescription dose.
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This is a presentation given at Varian users meeting (I think that was name) at ASTRO in 2001. About 2000 people in attendance iirc. I would call the presenter someone who most dosimetrists/physicists venturing into IMRT at that time very much listened to, for better or worse.

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I recall my attendings at one point, very very early on, doing 72/30 to tumor and 54/30 to ENI, SIB. (Why? 1.8 Gy should be the minimal daily Rx dose for H/N. Ergo, 30 fractions, and 70 divided by 30 didn't give a nice round number.) Those patients did quite poorly (laryngeal necrosis type stuff e.g.). I think 70/33 and 63/33 and 56/33 as SIB came from MSKCC. It was math/rad bio machinations, right? How to divide up the intended GTV-PTV Rx dose and keep the minimal ENI CTV at some reasonable "microscopic rad bio" dose.

I think getting a true reliable plan sum from different IMRT plans was difficult (if not annoying to try and do) prior to ~2000-2005.

This was also an era where people were widespread "doing stuff" before any stuff would be published.
 
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WildRivers said:
Another head neck RCT - A randomized prospective study comparing acute toxicity, compliance and objective response rate between simultaneous integrated boost and sequential intensity-modulated radiotherapy for locally advanced head and neck cancer

Not randomized, but anal cancer study showed skin better, but worse fecal incontinence with SIB - Comparative analysis of toxicity in patients with anal cancer undergoing definitive simultaneous integrated boost (SIB) or sequential integrated boost (SeqB) radiotherapy - PMC .. odd how they phrased the conclusion, though. 22% vs 10% fecal incontinence is a big deal

There's a few other, I'll likely write a post about this. Thesis - "SIBs are good for physicists and administrators focused on conformality and efficiency, while SEQ is better for biologic recovery and relevant adverse effects"
Click to expand...

As a physicist, I'm not sure why I'm supposed to like it? Especially since boost volumes change sometimes regularly. A true composite of mid-course replans with SIB would be more complex...
 
photonpowder said:
As a physicist, I'm not sure why I'm supposed to like it? Especially since boost volumes change sometimes regularly. A true composite of mid-course replans with SIB would be more complex...
Click to expand...
Glad you said that. Everyone tells me that physics and dosi prefer. Actually just got a text from someone that says the prefer sequential as well for anal unless the dosi gives him ****. I am not as familiar with dosi and physics workflows to know if it is harder.
 
WildRivers said:
Glad you said that. Everyone tells me that physics and dosi prefer. Actually just got a text from someone that says the prefer sequential as well for anal unless the dosi gives him ****. I am not as familiar with dosi and physics workflows to know if it is harder.
Click to expand...
maybe be harder but twice or more the remuneration
 
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