Second generation of familial nonmedullary thyroid carcinoma: A meta-analysis on the clinicopathologic features and prognosis.

Whether the second generation of parent/offspring type familial nonmedullary thyroid carcinoma (FNMTC) is more aggressive and has worse prognosis than their first generation counterpart is controversial. To evaluate the clinicopathologic features and prognosis of the second generation via a comparison between the two groups, We searched three databases (PubMed, EMBASE and the Cochrane library) to review studies published before November 25, 2016. All original studies comparing the clinicopathologic features and prognosis in the first generation of parent/offspring type FNMTC with its second generation counterpart were included. The Q-test and I test were used to evaluate homogeneity and funnel plot with Egger's test was used to evaluate publication bias. 6 studies, including 424 subjects were included. There was significant difference between the first and second generation of parent/offspring type FNMTC in the age of onset (SMD = -1.20, 95% CI: -2.38, -0.03, p = 0.045), gender distribution (OR = 0.48, 95% CI: 0.25, 0.90, p = 0.022) and lymph node metastasis (OR = 1.84, 95%CI: 1.16, 2.92, p = 0.01), while no significant difference in other variables. Thus we conclude that the second generation of parent/offspring type FNMTC patients is in higher risk than their first generation counterpart. We believe continuous study is needed to confirm the result.