Effects of exercise on circulating tumor cells among patients with resected stage I-III colon cancer.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 30332430 · doi:10.1371/journal.pone.0204875
What was done
Twenty-three patients with resected stage I-III colon cancer were randomized into three groups: usual-care control, low-dose aerobic exercise (150 min/wk), or high-dose aerobic exercise (300 min/wk) for six months. Circulating tumor cells (CTCs) from venous blood were measured in a blinded manner using a microfluidic antibody-mediated capture device, and logarithmic counts were analyzed with Poisson regression models.
What was found
At baseline, 78% (18/23) of patients had ≥1 CTC. Baseline CTC counts were associated with older age (-0.12±0.06; P = 0.04), lymphovascular invasion (0.63±0.25; P = 0.012), moderate/poor histology (1.09±0.34; P = 0.001), body mass index (0.07±0.02; P = 0.001), visceral adipose tissue (0.08±0.04; P = 0.036), insulin (0.06±0.02; P = 0.011), sICAM-1 (0.04±0.02; P = 0.037), and sVCAM-1 (0.06±0.03; P = 0.045). Over six months, CTCs significantly decreased in the low-dose (-1.34±0.34; P < 0.001) and high-dose (-1.18±0.40; P = 0.004) exercise groups, but did not significantly change in the control group (-0.59±0.56; P = 0.292). Decreases in body mass index (-0.07±0.02; P = 0.007), insulin (-0.08±0.03; P = 0.014), and sICAM-1 (-0.07±0.03; P = 0.005) correlated with CTC reductions.
Why it matters
This pilot study suggests aerobic exercise may decrease circulating tumor cells in stage I-III colon cancer, offering a plausible biological mechanism for exercise-related reductions in disease recurrence.
Limits
The trial had a very small sample size (n = 23 across three groups), used a per-protocol analysis, included a heterogeneous population across cancer stages I-III, and did not evaluate clinical recurrence or survival endpoints.
Cited by
- partial Engaging in physical activity reduces the risk of cancer recurrence and metastasis in individuals with circulating tumor cells.
- partial Studies by Kerry Courneya show that exercise directly destroys circulating tumor cells.