The effects of vascularization on tumor development: a systematic review and meta-analysis of pre-clinical studies.

Abstract Purpose This review aimed to systematize and quantify the existing evidence about the effect of tumor vascularization on its growth, in preclinical studies. Methodology A computerized research on databases PubMed, SCOPUS and EBSCO was performed to identify studies that evaluate both the vascularization parameters and the development of the tumors in animal models and the mean differences were calculated through a random effects model. Results Thirteen studies met the inclusion criteria and were included in the systematic review, of which, 6 studies were included in the meta-analysis. Besides tumor vascular density that all studies evaluated, 3 studies analysed the tumor perfusion, 2 studies the tumor hypoxia and 3 studies assessed the grade of vessel maturation. Most of the studies (11) related decreased tumor vascularization and a concomitant inhibition of tumor growth or metastasis development. Quantitatively, the decrease in tumor vascularization contributed to a significant decrease in the tumor growing rate of 5.23 (-9.20, -1.26). Conclusion A reduced level of tumor vascularization seems to be able to inhibit tumor growth and progression.