Thread by @cancerphysicist

Part II of today’s tweetorial for International clinical trials day: #CTD2019 #ICTD2019

Why do you want to give physicists a central role in your radiotherapy trials?

https://twitter.com/cancerphysicist/status/1130374463730671618

#medphys #radonc
@ipemnews @EFOMP_org @aapmHQ @EORTC @CTRad_CChan

First, what characterises medical physicists?
- We're quantitative, systematic & analytical
- We're trained in modelling, data visualisation, & interpretation of evidence

(And sometimes we - by which I mean me - go exploring in caves, which is almost like running a trial 😅)

But importantly, we understand the opportunities and limitations in current technology & are uniquely placed to understand current gaps in knowledge.

We can ask

“How can we best utilise technology to improve outcomes?”
“Will this be achievable in daily practice?”

Want to see examples? How about a phase I trial of failure probability-driven dose redistribution, designed by @IvanVogelius
ncbi.nlm.nih.gov/pubmed/26993418
This trial was based on outcome modelling and in silico studies, largely led by medical physicists

Or, for something more involved: The phase III NARLAL2 trial, an international trial of PET-driven dose escalation in NSCLC:
ncbi.nlm.nih.gov/pubmed/28688525
clinicaltrials.gov/ct2/show/NCT02…

This is based on years of work by a national Danish group of physicists: multicentre plan benchmarking to establish dose escalation technique, feasibility and effect size; simulations for sample size; national workshops on adaptive techniques; PET phantom benchmarking, etc.

(I’m not forgetting the dedicated clinicians involved, but today is all about the physicists 😉 )

Both trials are good examples of how physicists have used outcome modelling to drive radiotherapy trial designs

But we can do more!
(Even if you don’t feel comfortable letting us run conceptualization, development and trial design …)

How about adding a an imaging biomarker sub-study to your trial?

IQ-EMBRACE is an imaging sub-study of the EMBRACE II trial. It prospectively collects quantitative MRI for imaging biomarker discovery

sciencedirect.com/science/articl…
embracestudy.dk/UserUpload/Pub…

Or an IGRT sub-study?
clinicaloncologyonline.net/article/S0936-…

And when all the hard work is done and over, the trial has been completed, and you have collected all that data - why not use it for explorative analyses?

You could explore variations in outcome, as has been done for RTOG 0617:
ncbi.nlm.nih.gov/pubmed/28034064

But you could also look at that massive pile of complex radiotherapy data (hopefully collected as part of your trial QA?) and the excellent clinical outcome data ...
... and give it to the ones who have been exactly training to handle large data sets - the physicists! 😀

I’ll particularly highlight the data from the TROG 03.04-RADAR trial, which have been used for a series of exciting outcome modelling publications. E.g. spatial models of bladder dysfunction for different toxicity endpoints:
sciencedirect.com/science/articl…

Finally, you have your awesome trial of a completely novel radiotherapy technique - it’s positive! And you are going to change clinical practice! How is this going to happen?

Well, possibly something like this.

Clinicians all over the world will hand over the published protocol to their local physicists with “implement this!”

(Okay, they might do some of the work themselves. If we are lucky 😅)

Why not plan for this? Write the best possible trial radiotherapy guideline. But go further! Create a model for knowledge based planning & publish with your trial, for quick clinical implementation. See e.g. the FASTRACKII trial (TROG15.03) @HardcastleNick bmccancer.biomedcentral.com/articles/10.11…

Central message:
For a major radiotherapy trial, don't have "a trial physicist". Have a team of trial physicists!

This is the Danish Lung Cancer Radiotherapy group, who developed the NARLAL2 trial. Half of the group are physicists @MirjanaMedPhys

I hope I have convinced you of the value of medical physics for clinical trials! If not, we're just going to have to try with more cake 😁

(One of my own creations this time ...)

These tweetorials have been based on a talk that I gave at #ESTRO38 - where I also covered barriers to change, tips and tricks to get started, and more.

If you have access to the online content, why not go listing to me talk for half an hour?
webcasting.streamdis.eu/Mediasite/Play…

I got A LOT of help from many, many people in the radiotherapy community to prepare this - far too many to list here. But thank you! @marianneaznar @HardcastleNick @cementino @IvanVogelius @RTTQA_UK @MontefioreD

Why caving is like conducting a clinical trial
- requires teamwork to succeed
- half the time you're being led by somebody more experienced, hoping they know what they are doing
- the other half, you're just stumbling in the dark
- you come out the other end completely knackered