Jay Detsky

Excited to share our publication in @TheLancetOncol on the primary results from the UNITED study: a new paradigm in radiotherapy for patients with glioblastoma /1 @Sunnybrook @UofTDRO thelancet.com/journals/lanon…

New findings in glioblastoma show how MR‑guided adaptive radiotherapy can reduce treatment volumes by 40% while maintaining outcomes and a 4% marginal failure vs 11% historically. A step forward in delivering precise care and helping protect healthy brain tissue. 👉 Read the full study in The Lancet Oncology: bit.ly/4tLKIzT *Study by Detsky et al., UNITED trial investigators at Sunnybrook Health Sciences Centre.

@RO_GreenJournal @SahgalArjun @Elekta @Sunnybrook Here is a link with full article: sciencedirect.com/science/articl…

In fact the full paper was published just yesterday @RO_GreenJournal here: thegreenjournal.com/article/S0167-… @SahgalArjun @Elekta @Sunnybrook

This morning at #ESTRO26 our incredible rad onc fellow Dr Suman Ghosh @Suman_radonc gave a plenary oral digging deep into the inclusion/omission of FLAIR signal from the UNITED study. Well done Suman!

@Sunnybrook is having a pretty good weekend. Here is a nice secondary analysis of UNITED just presented at ESTRO 2026 and published in Green journal. Suggests FLAIR chasing does nit impact margin failure rates. @jaydetsky @SahgalArjun “Influence of FLAIR inclusion on patterns-of-failure and outcomes in glioblastoma: results from the UNITED prospective adaptive radiotherapy trial - Radiotherapy and Oncology” thegreenjournal.com/article/S0167-…

@TylerSbrt @TonyFelefly @joshuapalmermd @SahgalArjun Thanks Tyler! Appreciate the kind words. 1 cm CTV with 1 mid treatment MRI is our standard off trial, but I’d be nervous with smaller than that without close imaging monitoring. Cheers!

@jaydetsky @TonyFelefly @joshuapalmermd @SahgalArjun I hear you. Your paper is a big step forward! I’m a fan. And the impact will be positive. I simply suspect centers without an MRL or even adaptive can also likely adopt smaller margins w/o substantial detriment to local control. Great work!!

Excited to share our publication in @TheLancetOncol on the primary results from the UNITED study: a new paradigm in radiotherapy for patients with glioblastoma /1 @Sunnybrook @UofTDRO thelancet.com/journals/lanon…

@jjnaylor02 @TylerSbrt @TonyFelefly @joshuapalmermd @SahgalArjun I can only analyze what’s been published and I am familiar with the McDonald paper. 46 Gy to the FLAIR plus 7 mm then phase 2 14/7 to cavity/enhancing disease plus 5 mm. Not truly small margin IMHO sciencedirect.com/science/articl…

@TylerSbrt @jaydetsky @TonyFelefly @joshuapalmermd @SahgalArjun Agreed. Emory also has been using <1 cm margins since some of the faculty teaching me were residents themselves

@TylerSbrt @TonyFelefly @joshuapalmermd @SahgalArjun Also huge selection bias with 5-20 mm CTV based on physician discretion per case. Median OS 1 year for 60 Gy is inferior to modern day (maybe driven by less TMZ). No IDH or MGMT info

@TylerSbrt @TonyFelefly @joshuapalmermd @SahgalArjun I like this paper, I really do, but have you read it critically recently? -Literally no definition of GTV and probably 2-phase (?) based on this figure but who knows -Seems like huge volumes not small margin modern RT -Mostly 3D conformal and 1/3 no TMZ

@5_utr To be more specific, prior studies (at the time) had 11% risk of MF with 99% CI 5-23%, hence we thought 10% margin was reasonable. /3

@5_utr And here are more details re: sample size from our statistician, removed during the editing process with Lancet /2

@5_utr We did not believe that such small margins would be superior and were truly concerned about early increased marginal failures. /1

@SahgalArjun Addendum: full text of the paper available with this link: sciencedirect.com/science/articl…

I'd like to thank the patients and their families who volunteered to participate in this study despite a devastating diagnosis of GBM. Thanks to my co-authors and especially senior author and mentor @SahgalArjun /end

@HardenedBeam @Xristodouleas @IJROBP Published or presented anywhere? I’d love to see the outcomes and techniques

@jaydetsky @Xristodouleas @IJROBP This is cool but is certainly not special to an MRI linac as I use interval MRI imaging during proton therapy to keep tight margins and the dosimetry would blow an MRI linac out of the water.

@joshuapalmermd @SahgalArjun The amount of data from tumor dynamics from this cohort (eg methylation impact on migration and volume change, and theoretical coverage of evolving GTV using guideline margin recipes) is massive and more papers are in the pipeline!

@joshuapalmermd @SahgalArjun Hi Josh. I think offline adaptation using MR with contrast once a week would recreate the same results. For methylated tumors after 2-3 weeks q2weeks probably fine; we are trying to model how often repeat MR is needed

@toddscarbrough @SahgalArjun The graphical abstract I see now can be misleading Todd. Long and short course curves and outcomes are no worse than historical. You can’t compare these two groups they always have different outcomes. Better explained in the paper

@jaydetsky @SahgalArjun Hey Jay! How are the survivals not different, but actually different? The curves are pretty separated.