(BioMed Central, 2016) Meneses Echávez, José Francisco; González Jiménez, Emilio; Schmidt Río-Valle, Jacqueline; Correa Bautista, Jorge Enrique; Izquierdo Redín, Mikel; Ramírez Vélez, Robinson; Ciencias de la Salud; Osasun Zientziak
Background: Insulin-like growth factors (IGF´s) play a crucial role in controlling cancer cell proliferation,
differentiation and apoptosis. Exercise has been postulated as an effective intervention in improving cancerrelated
outcomes and survival, although its effects on IGF´s are not well understood. This meta-analysis aimed
to determine the effects of exercise in modulating IGF´s system in breast cancer survivors.
Methods: Databases of PuMed, EMBASE, Cochrane Central Register of Controlled Trials, EMBASE, ClinicalTrials.
gov, SPORTDiscus, LILACS and Scopus were systematically searched up to November 2014. Effect estimates were
calculated through a random-effects model of meta-analysis according to the DerSimonian and Laird method.
Heterogeneity was evaluated with the I2 test. Risk of bias and methodological quality were evaluated using the
PEDro score.
Results: Five randomized controlled trials (n = 235) were included. Most women were post-menopausal. Highquality
and low risk of bias were found (mean PEDro score = 6.2 ± 1). Exercise resulted in significant improvements
on IGF-I, IGF-II, IGFBP-I, IGFBP-3, Insulin and Insulin resistance (P < 0.05). Non-significant differences were found for
Glucose. Aerobic exercise improved IGF-I, IGFBP-3 and Insulin. No evidence of publication bias was detected by
Egger´s test (p = 0.12).
Conclusions: Exercise improved IGF´s in breast cancer survivors. These findings provide novel insight regarding the
molecular effects of exercise on tumoral microenvironment, apoptosis and survival in breast cancer survivors.
