Surgical Management of Low-/Intermediate-Risk Node Negative Thyroid Cancer: A Single-Institution Study Using Propensity Matching Analysis to Compare Thyroid Lobectomy and Total Thyroidectomy

Abstract

<b><i>Background:</i></b> The approach for surgical treatment of patients with low-/intermediate-risk T1T2N0/Nx well-differentiated thyroid cancer (WDTC)-total thyroidectomy (TT) versus thyroid lobectomy (TL)-remains a controversial topic. Conducting a randomized controlled trial (RCT) would be the gold standard to address this issue. However, this is challenging due to excellent survival outcomes, and therefore, high number of patients and long-term follow-up would be required. As an alternative to RCT, we have used propensity score (PS) matching to determine if T1T2N0/Nx patients selected to have TL had equivalent outcomes to a similar group treated with TT. <b><i>Methods:</i></b> After institutional review board approval, a database of 6259 patients with WDTC treated with primary surgery at our institution between 1985 and 2016 was analyzed to identify patients with T1T2N0/Nx cancers. Of 3756 patients identified, 943 were managed by TL and 2813 by TT. To control for possible confounders and reduce potential bias, we selected age, sex, histology, ¹³¹I therapy, American Thyroid Association risk, and American Joint Committee Cancer stage as our PS matching criteria. Subsequently, 918 TL patients were successfully matched with 918 TT patients. The Pearson χ² test or Fisher's exact test was used to compare categorical covariates, and Student's <i>t</i>-test was used for comparison of continuous variables between the two groups. Disease-specific survival (DSS), overall survival (OS), and recurrence-free survival (RFS) were calculated using the Kaplan-Meier method and compared using the log-rank test. <b><i>Results:</i></b> After PS matching, there were no significant differences between TL and TT patients for OS (10-year OS: 92.2% vs. 91.3%, <i>p</i> = 0.9668), DSS (10-year DSS: 100% vs. 99.1%, <i>p</i> = 0.1967), or RFS (10-year RFS: 99.5% vs. 98.3%, <i>p</i> = 0.079). <b><i>Conclusions:</i></b> For low-/intermediate-risk patients with intrathyroidal thyroid cancer <4 cm, patients selected for TL have similar survival outcomes to a comparable group treated by TT.