Catherine Seet-Lee1,2, Jasmine Yee1,2,3, Heidi Morahan1,2, Lois S Ross1,2,4, Kate M Edwards5,6. 1. Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, 2006, Australia. 2. Charles Perkins Centre, University of Sydney, Camperdown, Australia. 3. Centre for Medical Psychology & Evidence-Based Decision-Making, School of Psychology, The University of Sydney, Camperdown, Australia. 4. Department for Health, University of Bath, Bath, UK. 5. Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, 2006, Australia. kate.edwards@sydney.edu.au. 6. Charles Perkins Centre, University of Sydney, Camperdown, Australia. kate.edwards@sydney.edu.au.
Abstract
PURPOSE: Tumour blood vessels are structurally and functionally abnormal, resulting in areas of hypoxia and heterogeneous blood supply. Aerobic exercise may modulate tumour blood flow and normalise the tumour microenvironment to improve chemotherapy delivery. This systematic review and meta-analysis aimed to evaluate the effect of the aerobic exercise mode on tumour hypoxia, vascularisation and blood flow. METHODS: Four online databases were searched. Preclinical and clinical randomised controlled trials examining the effects of aerobic exercise training on hypoxia, vascularisation or blood flow in solid tumours were included. The risk of bias was assessed and a meta-analysis performed. RESULTS: Seventeen preclinical studies and one clinical study met criteria. Eleven studies assessed hypoxia, 15 studies assessed vascularisation and seven evaluated blood flow. There was large variability in measurement methods, tumour types and exercise program designs. The overall risk of bias was unclear in clinical and preclinical studies, owing to poor reporting. There was no significant effect of aerobic exercise on hypoxia (SMD = -0.17; 95% CI = -0.62, 0.28; I2 = 60%), vascularisation (SMD = 0.07; 95% CI = -0.40, 0.55; I2 = 71%) or blood flow (SMD = 0.01; 95% CI = -0.59, 0.61; I2 = 63%). CONCLUSION: There is heterogeneity in methodology, resulting in evidence that is inconsistent and inconclusive for the effects of aerobic exercise on hypoxia, vascularisation and blood flow. Most evidence of aerobic exercise effects on tumour blood flow is in animal models, with very limited evidence in humans.
PURPOSE: Tumour blood vessels are structurally and functionally abnormal, resulting in areas of hypoxia and heterogeneous blood supply. Aerobic exercise may modulate tumour blood flow and normalise the tumour microenvironment to improve chemotherapy delivery. This systematic review and meta-analysis aimed to evaluate the effect of the aerobic exercise mode on tumour hypoxia, vascularisation and blood flow. METHODS: Four online databases were searched. Preclinical and clinical randomised controlled trials examining the effects of aerobic exercise training on hypoxia, vascularisation or blood flow in solid tumours were included. The risk of bias was assessed and a meta-analysis performed. RESULTS: Seventeen preclinical studies and one clinical study met criteria. Eleven studies assessed hypoxia, 15 studies assessed vascularisation and seven evaluated blood flow. There was large variability in measurement methods, tumour types and exercise program designs. The overall risk of bias was unclear in clinical and preclinical studies, owing to poor reporting. There was no significant effect of aerobic exercise on hypoxia (SMD = -0.17; 95% CI = -0.62, 0.28; I2 = 60%), vascularisation (SMD = 0.07; 95% CI = -0.40, 0.55; I2 = 71%) or blood flow (SMD = 0.01; 95% CI = -0.59, 0.61; I2 = 63%). CONCLUSION: There is heterogeneity in methodology, resulting in evidence that is inconsistent and inconclusive for the effects of aerobic exercise on hypoxia, vascularisation and blood flow. Most evidence of aerobic exercise effects on tumour blood flow is in animal models, with very limited evidence in humans.
Authors: Jennifer M Wiggins; Alexander B Opoku-Acheampong; Dryden R Baumfalk; Dietmar W Siemann; Bradley J Behnke Journal: Exerc Sport Sci Rev Date: 2018-01 Impact factor: 6.230
Authors: Carlijn R Hooijmans; Maroeska M Rovers; Rob B M de Vries; Marlies Leenaars; Merel Ritskes-Hoitinga; Miranda W Langendam Journal: BMC Med Res Methodol Date: 2014-03-26 Impact factor: 4.615