Hürthle Cell Thyroid Carcinoma Treatment and Characteristics

Introduction to Hürthle Cell Thyroid Carcinoma

Hürthle cell thyroid carcinoma requires total thyroidectomy as the standard treatment, not lobectomy, due to its more aggressive behavior compared to other differentiated thyroid cancers, as recommended by the National Comprehensive Cancer Network (NCCN) 1, 2

Hürthle cell carcinoma (HCC) represents approximately 3% of all thyroid carcinomas 3
It presents most commonly as a solitary nodule, according to the National Comprehensive Cancer Network (NCCN) 3, 2

NCCN specifically notes that molecular diagnostics are not recommended for Hürthle cell neoplasms, due to high false-positive rates for malignancy 1

Total thyroidectomy is the standard treatment for Hürthle cell carcinoma, as recommended by the National Comprehensive Cancer Network (NCCN) 2, 1
If lymph nodes are positive, central neck dissection (level VI) and lateral neck dissection (levels II-IV, consider for level V) are recommended by the National Comprehensive Cancer Network (NCCN) 2
If nodes are negative, prophylactic central neck dissection may be considered (category 2B recommendation) by the National Comprehensive Cancer Network (NCCN) 2
All patients should receive TSH suppression therapy with levothyroxine, as recommended by the National Comprehensive Cancer Network (NCCN) 3
Radioactive iodine (RAI) ablation should be considered for residual thyroid tissue, according to the National Comprehensive Cancer Network (NCCN) 2
For clinically progressive or symptomatic disease not amenable to surgery, consider clinical trials or small molecule kinase inhibitors, as recommended by the National Comprehensive Cancer Network (NCCN) 2

The 10-year relative survival rate for Hürthle cell carcinoma is approximately 76%, which is lower than papillary (93%) and follicular (85%) carcinomas, according to the National Comprehensive Cancer Network (NCCN) 3, 4

Pitfall: Treating HCC with lobectomy alone can lead to inadequate management of this potentially more aggressive cancer, as warned by the National Comprehensive Cancer Network (NCCN) 1, 2

The National Comprehensive Cancer Network (NCCN) notes that molecular diagnostics may not perform well for Hürthle cell neoplasms, with high false-positive rates for malignancy 5, 6
Definitive diagnosis of Hürthle cell carcinoma requires histological evidence of capsular and/or vascular invasion, which can only be determined after surgical excision 7
Hürthle cell carcinoma cannot be definitively diagnosed by fine-needle aspiration (FNA) alone, as cytology cannot reliably distinguish between benign and malignant Hürthle cell neoplasms 8

Unlike some other thyroid cancers, there is no established association between Hürthle cell carcinoma and previous neck radiation exposure 7

"Pure" Hürthle cell carcinomas are defined as those with a Hürthle cell component exceeding 75% of the tumor, and HCC is now classified as a distinct type of differentiated thyroid cancer by the World Health Organization (WHO) 9, 10, 7
HCC presents with molecular abnormalities that distinguish it from conventional follicular carcinomas, and is generally less aggressive and less likely to present with lymph node metastases compared to other high-risk thyroid carcinomas 9

HCC with extensive vascular and/or capsular invasion should be managed like other high-risk carcinomas, with a risk of recurrence classified as high (30-55%) when HCC is associated with extensive vascular invasion (>4 foci) 9, 7
Surgical excision is necessary for definitive diagnosis and treatment of Hürthle cell carcinoma 7

The National Comprehensive Cancer Network (NCCN) notes that molecular diagnostics may not perform well for Hürthle cell neoplasms, with historically high false-positive rates for malignancy, resulting in 86% of patients with suspicious findings undergoing unnecessary surgery, highlighting the need for improved diagnostic tests 11, 12
Newer molecular tests, such as the Afirma Genomic Sequencing Classifier and ThyroSeq v3, show improved performance with sensitivities of 88.9% and 92.9% respectively, but data remain insufficient for routine recommendation 11, 12

For advanced, progressive Hürthle cell carcinoma not amenable to surgery, kinase inhibitors such as lenvatinib may be considered, as per the National Comprehensive Cancer Network (NCCN) guidelines 11, 12