The Effects of Physical Exercise on Tumor Vasculature: Systematic Review and Meta-analysis.
Level 5 - mechanism / opinion, no new human data
Systematic review and meta-analysis of preclinical animal studies
PubMed 34341974 · doi:10.1055/a-1533-1876
What was done
Authors conducted a systematic review and meta-analysis across PubMed, Scopus, and EBSCO to evaluate the effects of physical exercise on tumor vascular outcomes in preclinical animal models. Mean differences were calculated using a random-effects model across 13 included animal studies evaluating chronic (11 studies) and acute (2 studies) intratumoral vascular adaptations.
What was found
Across 13 studies involving 373 animals, regular physical exercise induced a statistically significant increase in tumor vascularization of 2.13 (95% CI: [1.07, 3.20], p < 0.0001). Chronic adaptations included higher tumor microvessel density in 4 studies, increased tumor perfusion in 2 studies, and reduced intratumoral hypoxia in 3 studies. Acute exercise adaptations included increased vascular conductance and reduced vascular resistance, improving tumor perfusion and attenuating intratumoral hypoxia.
Why it matters
This review aggregates evidence showing that exercise can improve tumor perfusion and vascularization in animal models, which may have implications for reducing tumor hypoxia and enhancing therapeutic delivery.
Limits
The review is exclusively based on preclinical animal models, limiting direct applicability to human cancer patients. The evidence base is modest (13 studies, 373 animals) with only two studies evaluating acute responses, and the abstract does not specify the exact measurement units or exercise protocols.
Cited by
- supports Preclinical studies show that exercise improves blood vessel density and quality in primary tumors, enhancing chemotherapy delivery and tissue oxygenation.