Prevalence and predictor for malignancy of contralateral thyroid nodules in patients with unilateral PTMC: A systematic review and meta-analysis

Abstract

Background: The presence of clinically negative nodules on the contralater al lobe is common in patients with unilateral papillary thyroid microcarci noma (PTMC). The appropriate operational strategies of contralateral thyroid nodules remain controversial. In this study, we analyzed clinical features that could be pred ictors for malignancy of contralateral thyroid nodules coexisting with diagnosed unilateral PTMC. Methods: The literatures published from January 2000 to December 2019 w ere searched in PubMed, Cochrane Library, Embase, Web of Science, CNKI, and Wan Fang database. Odds ratio (OR) with 95% CI was used to describe categorical va riables. Heterogeneity among studies was examined by the Q test and I 2 test; potential publication bias was detected by Harbord test and ‘trim and fill’ method. Results: In this meta-analysis, 2541 studies were searched and 8 studie s were finally included. The results showed that the rate of carcinoma in cont ralateral nodules was 23% (OR = 0.23, 95% CI = 0.18–0.29). The pooled data indicated that contralateral malignancy was not associated with age, gender, primary lesion size, ipsilateral central lymph node metastasis and multifocality of contralateral lesion. The following variables have correlations with an increased risk of contralateral malig nancy: Multifocality of primary carcinomas (OR = 3.93, 95% CI = 2.70–5.73, P < 0.0001), capsular invasion (OR = 1.61, 95% CI = 1.10–2.36, P = 0.01), and Hashimoto's thyroiditis (OR = 1.57, 95% CI = 1.13–2.20, P = 0.008). Conclusions: Based on our meta-analysis, the rate at which contralateral ma lignancies are preoperatively misdiagnosed as benign is 23%. The risk fact ors for contralateral malignancy in unilateral PTMC patients with contralateral clini cal negative nodules include multifocality of primary carcinomas, capsular invasion, and Has himoto's thyroiditis.