It has been widely known that inflammatory biomarkers play a crucial role in tumorigenesis, angiogenesis and metastasis. Exercise training has been proposed as a safe and effective non-pharmacological strategy in modulating inflammatory status among breast cancer patients; however this evidence remains unclear.
To determine the effects of exercise training in the blood parameters of Inflammatory biomarkers in Breast cancer patients through a metaanalysis of randomized-controlled trials.
PRISMA statement and the Cochrane Handbook were followed. Electronic searches were implemented in MEDLINE, CENTRAL, EMBASE, Scopus and DARE database to retrieve trials published between 1980- March 2014 providing effects of exercise interventions on pro-inflammatory biomarkers, such as interleukin (IL) -2, IL-6, IL-8, tumoral necrosis factor alpha (TNF-α) and C-reactive protein (CRP) in Breast cancer survivors. We conducted an Inverse of variance (IV) fixed-effects model in absence of heterogeneity (I2<50%); otherwise a random-effects model was selected. Standardized-Mean Differences (SMD) were calculated to estimate differences between groups (p<0.05 with 95% Confidence interval). Heterogeneity was measured with the Chi2 test (p<0.10) and I2statistics.
A total of 15 studies were included (n=1447; mean age= 51.6 years old). Exercise interventions resulted in positive effects for CRP (MD= 0.37, 95%CI, 0.04 to 0.71; p= 0.03; I2=15%), IL-2 (MD= -6.04, 85%CI, -11.41 to -0.67; p=0.03; I2=0%), IL-10 (-22.90, 95%CI, -41.27 to -4.53; p=0.001, I2=0%) and waist circumference as indicator of body composition (MD= -1.12, 95%CI, -2.06 to -0.18; p=0.02; I2=45%). Non-significant differences were observed for IL-6 and TNF- α. There was no evidence of publication bias.
These findings suggest that exercise improves the pro-inflammatory profile in breast cancer patients and consequently the immunological responses and the carcinogenic processes related to tumoral environment. Differences found for IL-10 provide novel evidence for the role of exercise as an effective anti-inflammatory intervention in Breast cancer patients.