Exercise has long been hailed as cancer-fighting magic, but is there hard evidence behind the hype? In this episode, we tackle the CHALLENGE trial, a large phase III study of colon cancer patients that tested whether prescribed exercise could improve cancer-free survival. We translate clinical jargon into plain English, show why ratio statistics make splashy headlines while absolute differences tell the real story, and take a detour into why statisticians think survival analysis is downright sexy. And we even bring in a classic reality show to make sense of the numbers.
Statistical topics
- Data and Safety Monitoring Board (DSMB)
- Hazard ratios
- Intention-to-treat analysis
- Interim analyses
- Kaplan-Meier curves
- Phase III trials
- Randomized clinical trial
- Rates and rate ratios
- Relative vs absolute differences
- Stratified randomization with minimization
- Survival analysis
- Time-to-event variables
Methodological morals
- “Ratio statistics sell headlines. Absolute differences sell truth.”
- “Survival analysis is this sexy stats tool that makes every moment and every Cox count.”
References
Thanks
Thanks to Caitlin Goodrich for the episode topic tip!
Kristin and Regina’s online courses:
Demystifying Data: A Modern Approach to Statistical Understanding
Clinical Trials: Design, Strategy, and Analysis
Medical Statistics Certificate Program
Writing in the Sciences
Epidemiology and Clinical Research Graduate Certificate Program
Programs that we teach in:
Epidemiology and Clinical Research Graduate Certificate Program
Find us on:
Kristin - LinkedIn & Twitter/X
Regina - LinkedIn & ReginaNuzzo.com
- (00:00) - Intro
- (05:42) - Two different types of cancer studies
- (08:12) - Why might exercise affect cancer?
- (10:05) - Phase III trials are different
- (12:40) - Who was in the CHALLENGE trial?
- (13:31) - Stratified randomization with minimization
- (15:05) - The exercise prescription
- (18:23) - What did the CHALLENGE trial measure?
- (19:10) - Disease-free survival
- (21:05) - Data and Safety Monitoring Board – what do they do?
- (23:41) - Participants and adherence to exercise
- (26:00) - Intention-to-treat analysis
- (29:04) - Survival analysis overview
- (30:57) - Kaplan-Meier curves
- (33:33) - Reality-show analogy
- (36:00) - Ratio statistics are confusing
- (38:36) - Hazard ratios
- (46:09) - Wrap-up, rating, and methodological morals
