CHEERS Trial and Hardcore statistical discussion

[Palex80]

Pembrolizumab Alone vs After Stereotactic Body Radiotherapy in Patients With Advanced NSCLC

This phase 2 randomized clinical trial assesses whether pembrolizumab after stereotactic body radiotherapy vs pembrolizumab alone enhances tumor response in patients with metastatic non–small cell lung cancer.

jamanetwork.com

Reminds me of the PEMBRO-RT trial - another negative positive trial (or positive negative trial?)...

"A statistical analysis indicated that with a sample of 74 patients, 37 in each arm, the trial would have a power of 82% with an odds ratio of 4 to detect the difference between a response rate of 20% in the control arm and 50% in the experimental arm at a 2-sided significance level of P < .10."

People seem to believe that RT-induced abscopal effects are going to be as effective and common as ... Imatinib for CML!

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[Mandelin Rain]

People seem to believe that RT-induced abscopal effects are going to be as effective and common as ... Imatinib for CML!

People in power are trying to convince medical students of this every day. Oligomets will save the field.....

Just another bad bet.

 

[theradiator]

People in power are trying to convince medical students of this every day. Oligomets will save the field.....

Just another bad bet.

Actually...the biggest proponent of the abscopal effect is Sylvia Formenti who ran a residency program that was shut down by the much maligned ACGME. Perhaps in some bizzaro world twist, she emerges as some type of hero?

 

[Mandelin Rain]

I have no doubt that the abscopal effect has occurred anecdotally in scattered patients in many practices. It's hard not to be enthusiastic when you see it in vivo, in one of your patients. 10 years ago, an IR doctor showed a series of images in tumor board after a cryoablation which pretty clearly demonstrated regression of distant disease off systemic therapy. Dude was over the moon, and referred to it as the abscopal effect of cryo and cited some retrospective literature. I'm sure caught a bunch of referrals from it. No such clinical presentations since.

Probably a fairly rare phenomenon. If you want to make your nut as a bench researcher, develop a predictive genomic or immunoresponse test for abscopal effects.

 

[evilbooyaa]

My only point about the 'abscopal' effect is that we are defining it differently than the seminal NEJM case report from melanoma.

RIght now everyone is obsessed with IO +/- SBRT all at the same time. This trial, the MSKCC H&N trial, Pembro-RT (although you could argue that was a positive trial)

The NEJM case report was patient on IO --> initial response/stable disease --> pt progresses in multiple sites --> SBRT to one of the growing lesions --> other lesions start to shrink as well.

I'm not a basic scientist so I'm sure somebody has some in vitro data to suggest why that's not the case, but that's the next venue to investigate before we completely write off the concept of abscopal effect. Similar to how we do SBRT for oligoprogressive disease.