P27: Follicular Thyroid Carcinoma with Nodal Metastases: A National Study

Friday, March 24, 2023

11:41 AM – 11:46 AM

Location: SSO HUB: Breast & Endocrine Zone

Poster Presenter(s)

Andrew M. Fleming, MD (he/him/his)

Surgery Resident
University of Tennessee Health Science Center
Memphis, Tennessee, United States

Disclosure information not submitted.

Author(s)

Andrew M. Fleming, MD (he/him/his)

Surgery Resident
University of Tennessee Health Science Center
Memphis, Tennessee, United States

Disclosure information not submitted.
LH

Leah E. Hendrick, MD, MS

Surgery Resident
The University of Tennessee Health Science Center, United States

Disclosure information not submitted.
Zachary E. Stiles, DO MS (he/him/his)

Fellow
Roswell Park Comprehensive Cancer Institute
Amherst, New York, United States

Disclosure information not submitted.
JD

Justin A. Drake, MD

Fellow in Complex General Surgical Oncology
Moffitt Cancer Center, United States

Disclosure information not submitted.
Jeremiah L. Deneve, DO

Assistant Professor of Surgery
University of Tennessee Health Science Center
Memphis, Tennessee, United States

Disclosure information not submitted.
OD

Olivia DeLozier, MD

Assistant Professor of Surgery
The University of Tennessee Health Science Center, United States

Disclosure information not submitted.
Paxton V. Dickson, MD

Associate Professor of Surgery
University of Tennessee Health Science Center
Memphis, Tennessee, United States

Disclosure information not submitted.

Introduction: Lymph node metastases (LNM) are uncommon in patients with follicular thyroid carcinoma (FTC). The current study evaluated predictors of LNM, their impact on overall survival (OS) and influence of extent of thyroidectomy and radioactive iodine (RAI) in FTC patients with LNM.

Methods: Patients with FTC who underwent thyroidectomy and lymph node (LN) evaluation were identified from the National Cancer Database. Patients with incomplete nodal staging or stage IV disease were excluded. Simple and multiple logistic regression were performed to assess variables associated with LNM. Time-to-event analysis assessed OS stratified by LN involvement. Cox proportional hazards model analyzed the impact of LNM on OS while adjusting for other risk factors. Subgroup analysis assessed the impact of extent of thyroidectomy and RAI on OS.

Results: Among 3,774 FTC patients identified for evaluation, 211 (5.6%) had LNM. On multivariable analysis of clinicopathologic factors, only tumor multifocality was significantly associated with LNM (OR 3.886; CI 2.290 – 6.525; p< .01). Independent of nodal substratification (N1a or N1b), LNM significantly decreased OS compared to patients with N0 disease (log-rank p< .01; Figure 1A). Cox proportional hazards regression analysis adjusting for age, gender, comorbid disease, tumor size, tumor grade, and tumor multifocality revealed that LNM was independently associated with increased patient mortality (HR 3.024; CI 1.329 – 6.206; p< .01). For each positive LN, the hazard of mortality increased by 9.7% (HR 1.097; CI 1.007 – 1.161; p< .01). Among patients with LNM, total thyroidectomy offered a trend toward improved OS compared with less than total thyroidectomy (log-rank p=.0513; Figure 1B). After total thyroidectomy, RAI did not confer a survival benefit (Figure 1C) except in patients with ≥4 LNM.

Conclusions: LNM are uncommon in patients with FTC but are an independent predictor of worse OS. The number of positive LNs was also associated with death. Tumor multifocality was predictive of LNM and should raise suspicion for pN1 disease. Total thyroidectomy appeared most appropriate in these patients while the benefit of RAI was limited to those with a high nodal burden.

Learning Objectives:

define the incidence of lymph node metastases in follicular thyroid carcinoma.
discuss the impact of lymph node metastases on overall survival for patients with follicular thyroid carcinoma.
describe the impact of extent of thyroidectomy and radioactive iodine therapy on overall survival for patients with follicular thyroid carcinoma and lymph node metastases.