Lymph node metastasis characteristics of papillary thyroid carcinoma located in the isthmus

Abstract

The frequency and pattern of lymph node metastasis and the extent of dissection for isthmic papillary thyroid carcinoma (PTC) remain unclear, and the aim of this present study was to evaluate these characteristics and to attempt to detect the best surgical protocol for isthmic PTCs. A total of 3185 consecutive patients with PTCs were reviewed. Of these patients, 47 with a single isthmic PTC were enrolled in our study, and matched 47 patients with a single PTC located in the unilateral lobe were randomly selected and added for comparison of their baseline tumor characteristics and lymph node metastasis characteristics. Univariate and multivariate analyses were performed to determine the risk factors for central lymph node metastasis in PTCs. The isthmic PTCs showed a higher rate of capsule invasion (P = .013) and advanced pathological N stage (P = .038) compared to the PTCs located in the lobe; meanwhile, pathological evidence of central lymph node metastasis (P = .040) was more frequent in the isthmic PTC group than in the control group. The univariate and multivariate analyses indicated that the tumors located in the isthmus (hazard ratio [HR]: 2.769; 95% confidence interval [CI]: 1.124–6.826; P = .027) and those with advanced (T2–4) pathological classifications (HR: 4.282; 95% CI: 1.224–14.976; P = .023) were independent risk factors for central lymph node metastasis in PTC patients. Due to the higher rate of pathological central lymph node metastasis and independent risk factors for central lymph node metastasis, total thyroidectomy, and bilateral central lymph node dissection should be considered the standard surgical protocol for isthmic PTCs.

<p>The Extent of Therapeutic Central Compartment Neck Dissection in Unilateral cT1N1a or cT2N1a Papillary Thyroid Carcinoma</p>

“…Previous studies have reported that patients with PTC located in the isthmus are more likely to have CLNM, especially pretracheal and prelaryngeal LNM, and bilateral CCND should be considered. [34][35][36] According to this study, male sex (p=0.005, OR=17.545) and the presence of an aggressive pathology (p=0.027, OR=48.063) were independent predictive factors of contralateral paratracheal LNM. Men are known to be at high risk for thyroid cancer.…”

Are clinicopathological features of the isthmic thyroid nodule different from nodules in thyroid lobes? A single center experience

“…In the literature, malignancy rate in isthmus region was reported between 1% and 17.4% in different studies (7,9,10,(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). In a study including 557 nodules with definitive cytologic diagnoses, although isthmic nodules had lower malignancy rate (2.5%), the rate was not significantly different in the isthmus, right (9.6%), or left lobe (7.2%) (8).…”

“…Prevalence of thyroid nodules located in isthmus was found as 4.2-6.4% (7,9,11). The incidence of isthmic papillary thyroid cancer (PTC) ranges from 1% to 12.3% in different studies (12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Although PTC had an indolent course, isthmic PTCs were reported to have more aggressive behaviour, including multifocality, capsular invasion, and frequently having metastasis to lymph nodes in some studies (12,16).…”

Isthmusectomy in selected patients with well‐differentiated thyroid carcinoma

“…4,[12][13][14]17,19 However, there are no specific data available in the literature for the management of WDTC confined to the thyroid isthmus with a long-term follow-up. 4,[12][13][14]17,19 However, there are no specific data available in the literature for the management of WDTC confined to the thyroid isthmus with a long-term follow-up.…”

“…Total thyroidectomy has been practiced for patients with WDTC located in the isthmus at many institutions. 4,[12][13][14]17,19 However, there are no specific data available in the literature for the management of WDTC confined to the thyroid isthmus with a long-term follow-up. 5 Current guidelines, including the 2015 ATA guidelines, 6 Korean Thyroid Association Guidelines, 7 Korean Association of Thyroid and Endocrine Surgeons Guidelines, 8 and British Thyroid Association guidelines 9 do not mention isthmusectomy as an acceptable procedure in the management of WDTC.…”