Prostate Single Fraction Treatment Discussion

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Palex80

Palex80

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1699023480832.png



The prostate is in the pelvis.
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TheWallnerus said:
I am convinced single fraction RT will work as well for prostate cancer, especially low to intermediate risk, as >1 fraction.
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It will only if one assumes that the a/b for prostate cancer is truly < 3 and that the formula holds at high doses, especially in a single fraction.

As we have learned thus far from Single Fx HDR data, something in the above statement is incorrect.

Given all the hypofrac trials SHOULD have shown superior oncologic outcomes (similar to ongoing from 70-->78Gy at 2Gy/fx) if a/b of prostate cancer was < 3 but instead have shown equivalent oncologic outcomes, the a/b of prostate cancer cannot be < 3. It may not be 10, but it's definitely not < 3.

I am prophylactically moving this to its own thread as I predict there will be lively dogmatic discussion in this regard.
 
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evilbooyaa said:
Given all the hypofrac trials SHOULD have shown superior oncologic outcomes (similar to ongoing from 70-->78Gy at 2Gy/fx) if a/b of prostate cancer was < 3 but instead have shown equivalent oncologic outcomes, the a/b of prostate cancer cannot be < 3. It may not be 10, but it's definitely not < 3.
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1699032017799.png
 
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evilbooyaa said:
It will only if one assumes that the a/b for prostate cancer is truly < 3 and that the formula holds at high doses, especially in a single fraction.

As we have learned thus far from Single Fx HDR data, something in the above statement is incorrect.

Given all the hypofrac trials SHOULD have shown superior oncologic outcomes (similar to ongoing from 70-->78Gy at 2Gy/fx) if a/b of prostate cancer was < 3 but instead have shown equivalent oncologic outcomes, the a/b of prostate cancer cannot be < 3. It may not be 10, but it's definitely not < 3.

I am prophylactically moving this to its own thread as I predict there will be lively dogmatic discussion in this regard.
Click to expand...


Hmmm.

Even if the a/b was 2, 78/39 still higher BED than 60/20 for example
 
Palex80 said:
View attachment 378645
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A chain is only as strong as its weakest link! A curative dose of radiotherapy is only as curative as the BED experienced by the most relatively radioresistant tumoral clonogen.
evilbooyaa said:
As we have learned thus far from Single Fx HDR data, something in the above statement is incorrect.
Click to expand...
They didn't use a big enough fraction ;)

If α/β for a tumor is 1.5, going from 19Gy/1fx to 20Gy/1fx gives as much BED boost as going from 70Gy/35fx to 78Gy/39fx. And 19Gy to 21Gy would be like going from 70Gy/35fx to ~86Gy/43fx. And so forth. Whether one believes the math or not, it at least serves as an idea about how far we may need to push single fraction doses in prostate to get the outcome we want. (@Palex80, the ideas go a bit kaput without α/β≤1.5 for all the cells.)
2023-11-03 12_33_38-(21_(1+21_1.5))_(19_(1+19_1.5))=(x_(1+2_1.5))_(70_(1+2_1.5)) - Wolfram_Alpha.png
 
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evilbooyaa said:
Given all the hypofrac trials SHOULD have shown superior oncologic outcomes (similar to ongoing from 70-->78Gy at 2Gy/fx) if a/b of prostate cancer was < 3 but instead have shown equivalent oncologic outcomes, the a/b of prostate cancer cannot be < 3. It may not be 10, but it's definitely not < 3.
Click to expand...

drowsy12 said:
Hmmm.

Even if the a/b was 2, 78/39 still higher BED than 60/20 for example
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@evilbooyaa should not have necessarily shown superior onc outcomes because the mathematical juice (lowered total Rx dose) didn't always keep up with the squeeze (increased fractional dose)
 
TheWallnerus said:
They didn't use a big enough fraction ;)

If α/β for a tumor is 1.5, going from 19Gy/1fx to 20Gy/1fx gives as much BED boost as going from 70Gy/35fx to 78Gy/39fx. And 19Gy to 21Gy would be like going from 70Gy/35fx to ~86Gy/43fx. And so forth. Whether one believes the math or not, it at least serves as an idea about how far we may need to push single fraction doses in prostate to get the outcome we want.
Click to expand...

I do not want a 21 Gy fraction delivered to my urethra or my anterior rectum wall.
 
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Gfunk6 said:
Euthanizing men with prostate cancer by delivery 21 Gy x1 fraction to the whole brain?

So you're telling me we are EXPANDING indications for radiotherapy!! :D
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Murder by cerebrovascular syndrome would be a pretty cool movie or TV crime plot I've always thought. Would be a mysterious healthy person death that would probably baffle the physicians.
 
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Fractionation....the simplest safety tool, yet reviled.
 
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communitydoc13 said:
Fractionation....the simplest safety tool, yet reviled.
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All about one up… basically the “name that tune” type of thing… yes, I’m old!

For those that don’t know, the contestants would try to name a song on the smallest amount of “notes” possible and whoever could name a song with the least amount would win.
 
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RadOncDoc21 said:
All about one up
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Agree. Fractionation is actually the most biologically elegant strategy for improving the therapeutic ratio when dealing with XRT alone.

The problem is...anyone can do it.

Lower fraction treatment is inherently riskier, usually not better for tumor control (with some exceptions) and almost always comes with a toxicity cost when keeping treatment volumes the same.

Not exciting.
 
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communitydoc13 said:
Agree. Fractionation is actually the most biologically elegant strategy for improving the therapeutic ratio when dealing with XRT alone.

The problem is...anyone can do it.

Lower fraction treatment is inherently riskier, usually not better for tumor control (with some exceptions) and almost always comes with a toxicity cost when keeping treatment volumes the same.

Not exciting.
Click to expand...

I should post this phrase around the clinic or put in new prostate patient info folders...
 
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TheWallnerus said:
Murder by cerebrovascular syndrome would be a pretty cool movie or TV crime plot I've always thought. Would be a mysterious healthy person death that would probably baffle the physicians.
Click to expand...
SAW, Chapter 17
 
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It seems increasingly obvious that hypofractionation was a ploy by “academic” centers to attract more patients to be treated by them as opposed to the community. They were never able to talk patients en masse into leaving their home for a full course of standard frac RT so this was a backdoor they could use.

For many years, dose escalation in prostate cancer showed improvement after improvement. They even had studies getting up to 90+ Gy with ever-improving outcomes.

Then they jumped on the hypofrac train and everything since has all been trying to prove equivalence, as opposed to actually improving outcomes. Not a single one of these studies has improved outcomes, but the toxicities are consistently greater in all of these studies, yet they are considered a win. It is a great disservice to our specialty and our patients, but is low hanging fruit for a lazy academic to achieve promotion.

A resident from a major academic institution shared with me a recent case in which a very standard SBRT, using ethos, resulted in a fistula and cystoprostatectomy and colostomy. Have you ever seen that from standard frac? I haven’t. And now they want to try even fewer fractions?
 
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I don't think single fraction will work. If it would, I don't think we'd have seen so many failures with single fraction brachy (19 Gy x 1)
 
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communitydoc13 said:
Agree. Fractionation is actually the most biologically elegant strategy for improving the therapeutic ratio when dealing with XRT alone.

The problem is...anyone can do it.

Lower fraction treatment is inherently riskier, usually not better for tumor control (with some exceptions) and almost always comes with a toxicity cost when keeping treatment volumes the same.

Not exciting.
Click to expand...
I have an honest discussion with patient.
I review the data between hypofrac + conventional including the toxicity difference. Have not had a patient choose hypofrac when given the choice.
 
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thesauce said:
It seems increasingly obvious that hypofractionation was a ploy by “academic” centers to attract more patients to be treated by them as opposed to the community. They were never able to talk patients en masse to leave their home for a full course of standard frac RT so this was a backdoor they could use.

For many years, dose escalation in prostate cancer showed improvement after improvement. They even had studies getting up to 90+ Gy with ever-improving outcomes.

Then they jumped on the hypofrac train and everything since has all been trying to prove equivalence, as opposed to actually improving outcomes. Not a single one of these studies has improved outcomes, but the toxicities are consistently greater in all of these studies, yet they are considered a win. It is a great disservice to our specialty and our patients, but is low hanging fruit for a lazy academic to achieve promotion.

A resident from a major academic institution shared with me a recent case in which a very standard SBRT, using ethos, resulted in a fistula and cystoprostatectomy and colostomy. Have you ever seen that from standard frac? I haven’t. And now they want to try even fewer fractions?
Click to expand...

I've seen it with standard frac once
 
We are approaching the realm of do you honestly have equipoise that one fraction could be safer or more effective . And if not, how do you enroll patients
Isn’t there already hdr data that 2 fractions is better than 1
 
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I don’t know. They kind of waffle in their conclusions.
 
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44, 39, 28, 25, 20, 5, 1...

michael cohen GIF


#fractionshaming
#ROCR
#deathtoRO
#noOARnocolostomy

I do 68/25 and bruh thats if they don't have a ginormous prostate/AUA issue.

Say it loud and proud kids: "I refuse to contribute to the demise of my specialty by literally fraction shaming ourselves right into oblivion."
 
sirspamalot said:
44, 39, 28, 25, 20, 5, 1...

michael cohen GIF


#fractionshaming
#ROCR
#deathtoRO
#noOARnocolostomy

I do 68/25 and bruh thats if they don't have a ginormous prostate/AUA issue.

Say it loud and proud kids: "I refuse to contribute to the demise of my specialty by literally fraction shaming ourselves right into oblivion."
Click to expand...
I do 70/28. Stop being part of the problem.😉
 
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radoncftw said:
I have an honest discussion with patient.
I review the data between hypofrac + conventional including the toxicity difference. Have not had a patient choose hypofrac when given the choice.
Click to expand...

💯 When fully and honestly informed, very few patients would choose hypofrac. A very short term improvement in convenience in exchange for increased risk of toxicity and ABSOLUTELY NO CLINICAL BENEFIT
 
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"She says the big ones hurt, but my spouses noninferiority study says its all good in the end"


noninferiority studies: making you feel inferior since 2015...

#fractionsizeshaming
 
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thesauce said:
💯 When fully and honestly informed, very few patients would choose hypofrac. A very short term improvement in convenience in exchange for increased risk of toxicity and ABSOLUTELY NO CLINICAL BENEFIT
Click to expand...
Just bad another pt choose standard yesterday. It's probably 60/40 favoring hypo. This isn't breast
 
thesauce said:
💯 When fully and honestly informed, very few patients would choose hypofrac. A very short term improvement in convenience in exchange for increased risk of toxicity and ABSOLUTELY NO CLINICAL BENEFIT
Click to expand...
the other elephant in the room is the RVU/revenue piece. I am constantly being scrutinized for how busy (or not busy) I am. It is nice to have some 44 Fx prostate patients on treat. I don't feel "greedy" because I have given them all of the options. I offer SBRT to all low and intermediate risk patients, but if I am treating nodes I am too chicken to do 25/5 to the whole pelvis.
 
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radoncftw said:
the other elephant in the room is the RVU/revenue piece. I am constantly being scrutinized for how busy (or not busy) I am. It is nice to have some 44 Fx prostate patients on treat. I don't feel "greedy" because I have given them all of the options. I offer SBRT to all low and intermediate risk patients, but if I am treating nodes I am too chicken to do 25/5 to the whole pelvis.
Click to expand...

Standard frac is a safe and appropriate treatment. If capitated payments come in, those doing standard frac will instantly go from greedy to a selfless person doing the right thing. Most of the “scrutiny” is virtue signaling and sour grapes and not worth being concerned over.
 
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Gfunk6 said:
We ought to ask the proton centers how many fractions they are delivering with their ultra-precise Bragg peak particles. 44 fractions???? What a shock.
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That’s what I see from academic centers in PA land
 
I like my rectum just the way it is, thank you very much. Please, try not to injure it.

-prostate standard fraction patient
 
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Palex80 said:
View attachment 378645
Click to expand...
Agreed, so we better stop assuming extremes if we want to kill all the cancer, right?

TheWallnerus said:
A chain is only as strong as its weakest link! A curative dose of radiotherapy is only as curative as the BED experienced by the most relatively radioresistant tumoral clonogen.

They didn't use a big enough fraction ;)

If α/β for a tumor is 1.5, going from 19Gy/1fx to 20Gy/1fx gives as much BED boost as going from 70Gy/35fx to 78Gy/39fx. And 19Gy to 21Gy would be like going from 70Gy/35fx to ~86Gy/43fx. And so forth. Whether one believes the math or not, it at least serves as an idea about how far we may need to push single fraction doses in prostate to get the outcome we want. (@Palex80, the ideas go a bit kaput without α/β≤1.5 for all the cells.)
View attachment 378648
Click to expand...

21Gy in 1 Fx to whole gland still failed: https://www.sciencedirect.com/science/article/pii/S1538472122001787
21Gy DIL also failed: https://www.thegreenjournal.com/article/S0167-8140(21)06144-2/fulltext
As did 20Gy in 1 Fx: https://www.sciencedirect.com/science/article/pii/S2405630822000696
 
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At what point does it become unethical to run a single-fraction prostate trial? Given the failed trials above, I would say we are past that point.
 
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OTN said:
At what point does it become unethical to run a single-fraction prostate trial? Given the failed trials above, I would say we are past that point.
Click to expand...
Right, when something is way more dangerous for little to nothing to gain.
 
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Coming soon to a Red Journal near you:


BRIEF REPORT|ARTICLES IN PRESS

Trends in Utilization and Medicare Spending on Short-Course Radiotherapy for Breast and Prostate Cancer: An Episode-Based Analysis from 2015-2019

Published December 07, 2023

PURPOSE
Evidence supports the value of shorter, similarly efficacious, and potentially more cost-effective hypofractionated radiotherapy (RT) regimens in many clinical scenarios for breast cancer (BC) and prostate cancer (PC). However, practice patterns vary considerably. We used the most recent Centers for Medicare and Medicaid Services data to assess trends in RT cost and practice patterns among episodes of BC and PC.

METHODS AND MATERIALS
We performed a retrospective cohort analysis of all external beam episodes RT (EBRT) for BC and PC from 2015-2019 to assess predictors of short-course RT (SCRT) utilization and calculate spending differences. Multivariable logistic regression defined adjusted odds ratios of receipt of SCRT over longer-course RT (LCRT) by treatment modality, age, year of diagnosis, type of practice, as well as the interaction between year and treatment setting. Medicare spending was evaluated using multivariable linear regression controlling for duration of RT regimen (SCRT vs LCRT) in addition to the covariables above.

RESULTS
Of 143,729 BC episodes and 114,214 PC episodes, 80,106 (55.73%) and 25,955 (22.72%) were SCRT regimens, respectively. Median total spending for SCRT regimens among BC episodes was $9,418 (IQR, $7,966-$10,982) vs. $13,601 (IQR, $11,814-$15,499) for LCRT. Among PC episodes, median total spending was $6,924 (IQR, $4,509-$12,905) for SBRT, $18,768 (IQR, $15,421-$20,740) for moderate hypofractionation, and $27,319 (IQR, $25,446-$29,421) for LCRT. On logistic regression, receipt of SCRT was associated with older age among both BC and PC episodes, as well as treatment at hospital-affiliated over freestanding sites (p<0.001 for all).

CONCLUSIONS
In this evaluation of BC and PC RT episodes from 2015-2019, we found that shorter-course RT resulted in lower costs vs. longer-course RT. SCRT was also more common in hospital-affiliated sites. Future research focusing on potential payment incentives encouraging SCRT when clinically appropriate and applicable in the two most common cancers treated with RT will be valuable as the field continues to prospectively evaluate cost-effective hypofractionation in other disease sites.
 
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