Increased blood flow and shear forces during exercise cause cell death of circulating tumor cells in a dose-dependent manner based on exercise intensity and duration.
"These circulating tumor cells are very sensitive to the shearing forces of blood flow. So when you exercise and blood flow increases, those circulating tumor cells, they actually die. And this happens in a dose-dependent manner: so the more intense the exercise, the more sensitive they are to cell death." (said at 0:48:45)
The claim is overstated because it presents an in vitro microfluidic finding as an established human in vivo phenomenon. In a laboratory circulatory system simulating exercise-associated hemodynamic forces (60 dynes/cm² vs. 15 dynes/cm² at rest), high shear stress caused substantial mechanical destruction (necrosis and subsequent apoptosis) of various cancer cell lines (PMID 28054593). However, this effect has not been directly demonstrated to eliminate circulating tumor cells in a dose-dependent manner in exercising human cancer patients.
- partial: High Shear Stresses under Exercise Condition Destroy Circulating Tumor Cells in a Microflu… (Scientific reports 2017)
"High shear stress of 60 dynes/cm 2 achievable during intensive exercise killed more CTCs than low shear stress of 15 dynes/cm 2 present in human arteries at the resting state. 2) High shear stress caused necrosis in over 90% of CTCs within the first 4 h of circulation." (abstract, results, passage verified)
pubmedfull study (doi)