Thread by @VPrasadMDMPH

Our new @vkprasadlab article is now out in Cancer Reports

We tackle the frequency (spoiler alert: BRISK) of assessment of progression in RCTs of cancer drugs

Want to learn more?
onlinelibrary.wiley.com/doi/epdf/10.10…
[thread]

First, remember that progression free survival is a time to event, composite endpoint

It is typically the time until 1 of 4 things happen
Death, New lesions, Growth (without shrinkage) or Growth (from Nadir).

Watch my free lecture series to learn more:

As a result PFS is binned

It has a stair-step pattern b/c imaging is assessed not continuously, but at pre-specified time points

One can imagine that as a result: how often you assess the endpoint is important.

Very frequent assessment is rare in the messy reality of life, but might be common in trials

This can turn even trivial changes in tumor growth in stat. significant p values of <0.05!

aka $

We assessed how often PFS was checked in trials in our paper

Indeed it is checked frequently. Often less than 8 weeks is mandated for protocol specified scans.

Relentless scanning may be a tactic to find significant results for small gains

In many cases, the frequency of scanning in trials is more than guideline recommendations

Our study could not find a difference in the hazard ratio comparing different trials with different scan intervals, but this caveat is important to consider 👇👇

A future study should compare real world scan intervals to trial scan intervals. If anyone has access to data & is interested; email our lab, we would love to collaborate
@vkprasadlab

Read the full paper here:
onlinelibrary.wiley.com/doi/epdf/10.10…