Complication Rates of Total Thyroidectomy vs Hemithyroidectomy for Treatment of Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-analysis

Abstract

Importance: Papillary thyroid microcarcinomas (PTMCs) have been associated with increased thyroid cancer incidence in recent decades. Total thyroidectomy (TT) has historically been the primary treatment, but current guidelines recommend hemithyroidectomy (HT) for select low-risk cancers; however, the risk-benefit ratio of the 2 operations is incompletely characterized.

Objective: To compare surgical complication rates between TT and HT for PTMC treatment.

Data sources: SCOPUS, Medline via the PubMed interface, and the Cochrane Central Register of Controlled Trials (CENTRAL); through January 1, 2021, with no starting date restriction. Terms related to papillary thyroid carcinoma and its treatment were used for article retrieval. This meta-analysis used the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline and was written according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) proposal.

Study selection: Original investigations of adults reporting primary surgical treatment outcomes in PTMC and at least 1 complication of interest were included. Articles evaluating only secondary operations or non-open surgical approaches were excluded. Study selection, data extraction, and risk of bias assessment were performed by 2 independent reviewers and conflicts resolved by a senior reviewer.

Data extraction and synthesis: Pooled effect estimates were calculated using a random-effects inverse-variance weighting model.

Main outcomes and measures: Cancer recurrence and site, mortality (all-cause and disease-specific), vocal fold paralysis, hypoparathyroidism, and hemorrhage/hematoma. Risk of bias was assessed using the McMaster Quality Assessment Scale of Harms scale.

Results: In this systematic review and meta-analysis, 17 studies were analyzed and included 1416 patients undergoing HT and 2411 patients undergoing TT (HT: pooled mean [SD] age, 47.0 [10.0] years; 1139 [84.6%] were female; and TT: pooled mean [SD] age, 48.8 [10.0] years; 1671 [77.4%] were female). Patients undergoing HT had significantly lower risk of temporary vocal fold paralysis compared with patients undergoing TT (3.3% vs 4.5%) (weighted risk ratio [RR], 0.4; 95% CI, 0.2-0.7), temporary hypoparathyroidism (2.2% vs 21.3%) (weighted RR, 0.1; 95% CI, 0.0-0.4), and permanent hypoparathyroidism (0% vs 1.8%) (weighted RR, 0.2; 95% CI, 0.0-0.8). Contralateral lobe malignant neoplasm recurrence was 2.3% in the HT group, while no such events occurred in the TT group. Hemithyroidectomy was associated with a higher overall recurrence rate (3.8% vs 1.0%) (weighted RR, 2.6; 95% CI, 1.3-5.4), but there was no difference in recurrence in the thyroid bed or neck.

Conclusions and relevance: The results of this systematic review and meta-analysis help characterize current knowledge of the risk-benefit ratio of HT vs TT for treatment of PTMC and provide data that may have utility for patient counseling surrounding treatment decisions.

Figure 1.. Summary of VFP Complications From Meta-analysis Results

Forest plots summarizing the effect size of HT vs total thyroidectomy and risk of temporary VFP (A) and permanent VFP (B). Studies are shown in ascending order of their weight in the meta-analysis according to the inverse-variance weighting technique. The 95% confidence interval is shown for each individual study, and represented by the width of the diamond in the pooled estimate. HT indicates hemithyroidectomy; VFP, vocal fold paralysis.

Figure 2.. Summary of Hypoparathyroidism Complications From Meta-analysis Results

Forest plots summarizing the effect size of HT vs total thyroidectomy and risk of hypoparathyroidism (A) or permanent hypoparathyroidism (B). Studies are shown in ascending order of their weight in the meta-analysis according to the inverse-variance weighting technique. The 95% confidence interval is shown for each individual study, and represented by the width of the diamond in the pooled estimate. HT indicates hemithyroidectomy.

Figure 3.. Summary of Recurrence From Meta-analysis Results

Summary of risk and site of recurrence in HT vs TT. A, Funnel plot showing relative risk of recurrence in HT compared with TT reported by each study included in the weighted meta-analysis; points marked by different symbols for each site of recurrence. Each point is a single study. Points to the right of the vertical dotted line represent higher recurrence risk in HT. Points higher on the plot represent studies with lower variance in reported recurrence rates. B, Forest plot summarizing the effect size of HT vs TT on risk of recurrence at any site. Studies shown in ascending order of their weight in the meta-analysis according to the inverse-variance weighting technique. The 95% CI is shown for each study and is represented by the width of the diamond in the pooled estimate. HT indicates hemithyroidectomy; OR, odds ratio; SE(log[OR]), standard error of the log odds ratio; TT, total thyroidectomy.

Figure 4.. Risk of Bias

Risk of bias analyses for all included studies. A, Bar chart of magnitude and sources of bias for each of 4 questions selected from the McMaster Quality Assessment Scale of Harms (McHarm); B, Risk of bias assessment for each study, in order of publication date.