Positive Lymph Node Counts in American Thyroid Association Low‐Risk Papillary Thyroid Carcinoma Patients

Abstract

Background Current American Thyroid Association (ATA) guidelines state that patients with intermediate‐risk papillary thyroid cancer (PTC) may benefit from remnant ablation. One criterion for intermediate‐risk classification is >5 positive lymph nodes (LNs). We investigate whether performing step‐sectioning of LNs increases the metastatic detection rate, thereby influencing ATA risk of recurrence (ROR) classification. Methods A retrospective review was conducted of cases in which ≥ 5 LNs were removed during thyroidectomy and ≤5 LNs were found positive for PTC. Step‐sectioning was performed on the original tissue blocks. All slides were re‐reviewed by a senior pathologist. Results Twenty patients met study criteria. Step‐sectioning significantly increased LN yield compared to standard sectioning. In total, we found 12 new positive lymph nodes; seven (58%) were in totally new lymph nodes, while five (42%) were in lymph nodes previously read as negative. All newly discovered metastases were classified as micrometastases (≤2 mm). Of the 15 patients originally classified as low‐risk, the step‐sectioning protocol impacted two patients (13%), increasing ROR stratification. Conclusion Intensive step‐sectioning reveals additional micrometastases. More detailed analysis did not identify clinically significant nodal disease likely to impact the clinical course of patients in this study. Our study supports current standards of pathology specimen handling related to LN assessment and the impact on ATA ROR classification. Nonetheless, it is important for clinicians to understand their institution's sectioning protocol utilized to report positive and total LN counts, which could impact ATA risk stratification and denote the comprehensive nature of the LN dissection that was performed.

The Impact of Total Tumor Diameter on Lymph Node Metastasis and Tumor Recurrence in Papillary Thyroid Carcinomas

“…Then again, some of the thyroid carcinomas may present in a clinically aggressive manner, mainly due to localized and distant recurrences. Current guidelines stratify the patient groups at risk for PTC based on parameters that predict the recurrence of tumors, such as tumor size, ETE, LNM, and BRAF/TERT mutations [4,38]. Nevertheless, decision making regarding the clinical management of PTCs can be challenging, especially considering the still controversial multifocal and bilateral tumors.…”

MicroRNA profiling predicts positive nodal status in papillary thyroid carcinoma in the preoperative setting

“…However, metastases in lymph nodes are frequently microscopic and may be missed by clinical or ultrasound evaluation, and even by intraoperative frozen section. The clinical impact of underestimating lymph node metastases in papillary carcinoma patients because of microscopic metastases has been recently discussed in an article on American Thyroid Association risk stratification, 48 but it also applies in this context. Therefore, in cN0 patients, the risk of lymph node metastases is not negligible and prophylactic sampling or dissection of homolateral central neck or even homolateral lateral neck compartments (with or without intraoperative frozen section) are considered, although with no strict criteria for patient selection.…”