A Role for Resistance Exercise in Cancer: Destruction of Circulating Tumor Cells in Contracting Muscle

OBJECTIVE At the Roswell Park Cancer Institute in the 1980s, Leonard Weiss explored why muscle tissue gets few cancer metastases, despite its large blood flow. (Weiss, L., 1992. Biomechanical interactions of cancer cells with the microvasculature Cancer Metastasis Rev, 11(3), pp.227–235). He found that circulating tumor cells were destroyed in contracting quadriceps muscles and cardiac tissue, and during maximal lung inspiration. He further showed that as cancer cells squeeze through the much smaller capillaries, they elongate to the maximum extension of the cell membrane and hypothesized that additional forces on the cancer cell wall caused cell rupture. We analyzed Weiss’ published lung data during a maximal inspiration, and found this induces radial stress of 8.7 KpA on a 4.6 mm diameter lung capillary. In our study, mathematical models were applied to ultrasound generated architectural data of the contracting biceps muscle, to determine radial stress under different exercise conditions. METHODS 12 hea...