Microvessel density in differentiated thyroid carcinoma: A systematic review and meta-analysis.

Background: Microvessel density (MVD) has been proposed as a direct quantification method of tumor neovascularization. However, the current literature regarding the role of MVD in differentiated thyroid carcinoma (DTC) remains inconclusive.

Aim: To appraise the effect of tumoral MVD on the survival of patients with DTC.

Methods: This meta-analysis was based on the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. The electronic databases Medline, Web of Science, and Scopus were systematically screened. A fixed-effects or random-effects model was used, according to the Cochran Q test. The data were then extracted and assessed on the basis of the Reference Citation Analysis (https://www.referencecitationanalysis.com/).

Results: A total of nine studies were included in the present study. Superiority of low MVD tumors in terms of 10-year disease free survival (OR: 0.21, 95%CI: 0.08-0.53) was recorded. Lowly vascularized thyroid cancers had a lower recurrence rate (OR: 13.66, 95%CI: 3.03-61.48). Moreover, relapsing tumors [weighed mean difference (WMD): 11.92, 95%CI: 6.32-17.52] or malignancies with regional lymph node involvement (WMD: 8.53, 95%CI: 0.04-17.02) presented with higher tumoral MVD values.

Conclusion: MVD significantly correlates with the survival outcomes of thyroid cancer patients. However, considering several study limitations, further prospective studies of higher methodological and quality level are required.