FLAME TRIAL prostate boost - ?lymph nodes?

[evilbooyaa]

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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%)."

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

https://www.sciencedirect.com/science/article/pii/S2588931123001992

 

[sirspamalot]

Bowel prep is gasX and watching that diet. And showing up for treatment.

 

[SneakyBooger]

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

https://www.sciencedirect.com/science/article/pii/S2588931123001992

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.

 

[evilbooyaa]

Randomised Ph II, not ph III, hence low pt numbers.

 

[Chartreuse Wombat]

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.

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

 

[evilbooyaa]

?? It's 3 vs 4%. What are CI or HR going to add for you here?

 

[Chartreuse Wombat]

?? It's 3 vs 4%. What are CI or HR going to add for you here?

Confidence in your inference or not.

 

[SneakyBooger]

I keep thinkin bout those low numbers...

They must have used SpaceOAR!

 

[Medapp14]

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.

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).

 

[TheWallnerus]

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).

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.

 

[ramsesthenice]

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.

Thats what I do.

 

[BobbyHeenan]

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.

Thats what I do.

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.

 

[Palex80]

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.

This is basically the essence of our entire profession.

 

[ramsesthenice]

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.

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]

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.

 

[Neuronix]

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.

Which patient outcomes?

MIRAGE studied a common variation (PTV size) rigorously and found a difference in patient outcomes.

 

[TheWallnerus]

Which patient outcomes?

MIRAGE studied a common variation (PTV size) rigorously and found a difference in patient outcomes.

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.

 

[Neuronix]

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.

G2 toxicities very well may be. I don’t think they’re well recorded or reported.

 

[evilbooyaa]

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).

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.