Whole brain dose

[deleted1111261]

Does anyone have an evidence based reason to offer greater than 10 fractions for whole brain radiation therapy?

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[jondunn]

I like this paper as to why we shouldnt be going past 30/10

Optimizing Whole Brain Radiation Therapy Dose and Fractionation: Results From a Prospective Phase 3 Trial (NCCTG N107C [Alliance]/CEC.3) - PubMed

This post hoc analysis does not demonstrate that protracted WBRT courses reduce the risk of cognitive deficit, improve tumor control in the hypoxic surgical cavity, or otherwise improve the therapeutic ratio. Adverse events were significantly higher with the lengthened course of WBRT. For...

pubmed.ncbi.nlm.nih.gov

 

[Mandelin Rain]

Anyone remember the rationale for 0614 going to 3750 cGy in 15 fractions as the standard WBRT dose?

 

[TheWallnerus]

Does anyone have an evidence based reason to offer greater than 10 fractions for whole brain radiation therapy?

NEVER done it but it's evidence

 

[deleted1116990]

Does anyone have an evidence based reason to offer greater than 10 fractions for whole brain radiation therapy?

In the rare circumstances you get a colorectal brain met, you can justify going to 15 or 20 fraction...

Dose escalation in patients receiving whole-brain radiotherapy for brain metastases from colorectal cancer - PubMed

These data suggest that patients with brain metastases from colorectal cancer treated with WBRT alone appeared to benefit from escalation of the radiation dose beyond 10 x 3 Gy in terms of improved OS and LC.

pubmed.ncbi.nlm.nih.gov

 

[deleted1111261]

In the rare circumstances you get a colorectal brain met, you can justify going to 15 or 20 fraction...

Dose escalation in patients receiving whole-brain radiotherapy for brain metastases from colorectal cancer - PubMed

These data suggest that patients with brain metastases from colorectal cancer treated with WBRT alone appeared to benefit from escalation of the radiation dose beyond 10 x 3 Gy in terms of improved OS and LC.

pubmed.ncbi.nlm.nih.gov

Interesting. Not great evidence, but interesting.

 

[deleted1116990]

Interesting. Not great evidence, but interesting.

Caveat: In the rare circumstance you have a colorectal patient with brain mets AND in whom WBRT is indicated. I've had both conditions be met exactly once.

 

[deleted1111261]

So, it’s not that it’s safer to do protracted - the idea is that it is for specific histology?

 

[deleted1116990]

So, it’s not that it’s safer to do protracted - the idea is that it is for specific histology?

That was my understanding, the more radioresistant nature of colorectal potentially benefitted from dose escalation. You could potentially pump more dose in 10 fractions like 35/10 or something, but I wouldn't do that to the whole brain. The a/b of colorectal is about 5. BED5 of 30/10 is 48 Gy. For 40/20 it's 56, and for 45/15 it's 72. They've lumped 40/20 and 45/15 together, and the BED is pretty different between those two. I would do 37.5/15 (same BED as 40/20 in this case) if I were going to deviate, but if you really wanted to dose escalate, I think it would make sense to split the difference and do 42.5 in 17, which gives you a BED5 of 64. Based on nothing of course other than feeling squishy doing an extra 50% of 3 Gy fractions to the brain. I would not consider giving 45 Gy in 15 fractions to the whole brain. Like you said, not great data, but since you asked...

 

[Mandelin Rain]

NEVER done it but it's evidence

This is a huge issue.

As a field, we keep wondering if less radiation is "not worse". Here's a team that wondered if more radiation is "better". And it was. And no one has ever heard of this, done this, or explored it further.

Such a shame.

 

[deleted1111261]

This is a huge issue.

As a field, we keep wondering if less radiation is "not worse". Here's a team that wondered if more radiation is "better". And it was. And no one has ever heard of this, done this, or explored it further.

Such a shame.

Well, comparison to 20/4 seems a bit .. not right, but fair point.

 

[TheWallnerus]

And you have the Patchell (world's biggest WBRT fan and he's not even a rad onc) trial; the only randomized postop WBRT trial? We still refer to that right?

 

[deleted1116990]

I will never forget the time in chart rounds in residency one of the community doctors tried to present a 20 fraction whole brain plan...

 

[Mandelin Rain]

Well, comparison to 20/4 seems a bit .. not right, but fair point.

Definitely. But who knows? Maybe that was SOC in Australia in the early 2000s.

Obviously, WBRT kind of died shortly after that paper was published, but we still do it on rare occasion. We should be giving the best outcomes possible for those patients. Not just defaulting to 30/10 for reasons unknown.

 

[TheWallnerus]

WBRT kind of died shortly after that paper was published

Man BACK IN MY DAY whole brain RT patients almost ruled the roost in the RT department. Now they're rare as hen's teeth.

 

[deleted1111261]

Definitely. But who knows? Maybe that was SOC in Australia in the early 2000s.

Obviously, WBRT kind of died shortly after that paper was published, but we still do it on rare occasion. We should be giving the best outcomes possible for those patients. Not just defaulting to 30/10 for reasons unknown.

What is your general approach for dose / fx ?

Honestly, I had not heard in this era doing any thing more than 30 / 10, but sounds like it is more common than I thought. Just trying to sort out if this had some evidence behind it or just a style thing.

 

[Mandelin Rain]

What is your general approach for dose / fx ?

Honestly, I had not heard in this era doing any thing more than 30 / 10, but sounds like it is more common than I thought. Just trying to sort out if this had some evidence behind it or just a style thing.

Oh, I'm definitely part of the problem.

I do 30/10, but honestly, I do like 2 WBRTs per year. Used to be 37.5 in 15 while we were accruing to 0619 and the several years after that. But I've since back slid into the 30/10 comfort zone.

 

[CaesarRO]

I like this paper as to why we shouldnt be going past 30/10

Optimizing Whole Brain Radiation Therapy Dose and Fractionation: Results From a Prospective Phase 3 Trial (NCCTG N107C [Alliance]/CEC.3) - PubMed

This post hoc analysis does not demonstrate that protracted WBRT courses reduce the risk of cognitive deficit, improve tumor control in the hypoxic surgical cavity, or otherwise improve the therapeutic ratio. Adverse events were significantly higher with the lengthened course of WBRT. For...

pubmed.ncbi.nlm.nih.gov

Agreed, this is my go to answer.

Ironically the 40 Gy in 20 BID fractions noted above has more patients and I've also never seen it before.

 

[SneakyBooger]

Depends what you are looking for but maybe you can find something here:

the references:

Title Page:

 

[SneakyBooger]

Agreed, this is my go to answer.

Ironically the 40 Gy in 20 BID fractions noted above has more patients and I've also never seen it before.

Yeah, except post hoc analysis = meh (for me).

And when I look at the graphs, sure looks like longer fractionation might be better actually. If this were an industry sponsored study on a new immunotherapy they would be singing the praises of 3750 with data like that. Imagine what SpaceOAR would do with that $830K data.

 

[TheWallnerus]

What is your general approach for dose / fx ?

Honestly, I had not heard in this era doing any thing more than 30 / 10, but sounds like it is more common than I thought. Just trying to sort out if this had some evidence behind it or just a style thing.

The wikibook WBRT page actually has a good run down of this history. There’s not great evidence that 30/10 is better than 20/5 though either. I also was an ardent user of 37.5/15 after the RTOG WBRT+SRS trial was the number one ASTRO plenary that one year. Anna Gregor gave very fascinating talks on fraction size and cognition back in the day. Patchell believes in lower fraction sizes. At the end of the day, there's scant data there too re: neurocognition.

I always felt that the 40/20 bid WBRT phIII trial was a Type 1 error. (Although it did appealingly use 2 Gy fraction sizes!) But yes it should have been tested further. No one from the Ivory Tower pronounced it worthy of consideration, so it landed with a thud and evaporated from collective memory.

 

[evilbooyaa]

I cannot think of a strong reason to do > 10Fx for someone receiving whole brain for palliation of brain metastases from solid malignancy. I presume that lymphomas, leukemias, etc. are not the question here as there is reason to go ~2Gy/day for upwards of 15+ fx in those situations with whole brain.

Caveat: In the rare circumstance you have a colorectal patient with brain mets AND in whom WBRT is indicated. I've had both conditions be met exactly once.

Agreed. N of 0 for me. CRC with brain mets... those are getting SRS vast majority of time.