Management of regional metastases in well-differentiated thyroid cancer

Updates from Our Institutional Experience with Thyroid Nodules Diagnosed as Metastases

BACKGROUND

Thyroid metastases (TMs) are a rare entity, ranging between 0 and 24% in the autopsy series. In the assessment of the best management, the discrimination between a primary and a metastatic thyroid lesion is crucial. In this regard, fine needle aspiration cytology (FNAC) is likely to play a crucial role especially when ancillary techniques (i.e., immunocytochemistry (ICC) and molecular testing) are carried out.

METHODS

We searched for all the TMs diagnosed using FNAC and analyzed between 2014 and 2023. The cases were processed with liquid-based (LBC) and ICC and molecular testing performed on LBC-stored material.

RESULTS

We reported 2.2% (19 cases) of TMs out of 1022 malignancies. TMs included: 1 larynx carcinoma (LX-Ca), 1 melanoma, 2 breast carcinomas (B-Ca), 3 lung carcinomas (LG-Ca), 4 gastro-intestinal carcinomas (GI-Ca), and 8 clear cell renal carcinomas (CCRC). All patients had a previous cancer history, between 300 and 2 months from the primary cancers. The morphological features were supported by ICC, which were contributive in 100% of cases. All TMs cases were characterized by multiple thyroid nodules except the melanoma case. Four cases underwent total thyroidectomy (1 B, 1 LX, 1 melanoma, and 1 CCRC) whilst 15 TMs were treated with radio-chemotherapy.

CONCLUSIONS

FNAC empowered the diagnostic workup of patients with TMs avoiding useless surgery. The low sensitivity of cytology might be reinforced by the application of ancillary techniques. We found a predominant rate of kidney metastatic carcinomas, followed by lung and breast. TMs are frequently multifocal and in a context of a systemic disease so a tailored therapy seems to be the best treatment.

Video mediastinoscopy-assisted superior mediastinal dissection in the treatment of thyroid carcinoma with mediastinal lymphadenopathy: preliminary results

Background

Mediastinal lymph node metastases (MLNM) are not rare in thyroid cancer, but their treatment has not been extensively studied. This study aimed to explore the preliminary application of video mediastinoscopy-assisted superior mediastinal dissection in the diagnosis and treatment of thyroid carcinoma with mediastinal lymphadenopathy.

Materials and methods

We retrospectively reviewed the clinical pathologic data and short-term outcomes of thyroid cancer patients with suspicious MLNM treated with video mediastinoscopy-assisted mediastinal dissection at our institution from 2017 to 2020.

Results

Nineteen patients were included: 14 with medullary thyroid carcinoma and five with papillary thyroid carcinoma. Superior mediastinal nodes were positive in nine (64.3%) patients with medullary thyroid carcinoma and in four (80.0%) patients with papillary carcinoma. No fatal bleeding occurred. There were three cases of temporary recurrent laryngeal nerve (RLN) palsy postoperatively, one of which was bilateral. Four patients had temporary hypocalcemia requiring supplementation, one had a chyle fistula, and one developed wound infection after the procedure. Postoperative serum molecular markers decreased in all patients. One patient died of cancer while the other 18 patients remained disease-free, with a median follow-up of 33 months.

Conclusion

Video mediastinoscopy-assisted superior mediastinal dissection can be performed relatively safely in patients with suspicious MLNM. This diagnostic and therapeutic approach may help control locoregional recurrences.

Lateral neck multilevel fine-needle aspiration cytology and thyroglobulin estimation in papillary thyroid carcinoma

OBJECTIVE

To assess the accuracy of preoperative ultrasound-guided multilevel fine-needle aspiration (FNA) cytology and thyroglobulin (Tg) estimation in mapping metastatic levels in the lateral neck, in patients with papillary thyroid carcinoma (PTC).

METHODS

Patients with PTC clinically metastasizing to the lateral neck who were initially treated at the Peking University Cancer Hospital from June 2018 to September 2020 were included. FNA was performed preoperatively in each suspicious neck level; cytological examination (FNA-C) and Tg measurement of the needle-washout fluid (FNA-Tg) were combined to determine metastasis. FNA-Tg cutoff value was calculated, and the accuracy of FNA at different levels were evaluated.

RESULTS

In total, 111 patients underwent 124 lymph node dissections. The best cutoff value of FNA-Tg for the diagnosis of metastatic level was 1.0 ng/mL. Multilevel FNA showed sensitivity, specificity, positive predictive value, and negative predictive value in predicting single-level metastasis of 100%, 61.0%, 43.9%, and 100%, respectively. In 64 (51.6%) cases, the involved levels diagnosed by FNA were consistent with that diagnosed by postoperative pathology.

CONCLUSION

FNA-Tg improves the diagnostic performance of FNA-C in lateral neck lymph node metastases. However, limited accuracy was obtained for preoperative multilevel FNA in predicting the extent of metastasis in the lateral compartment.

Neck Dissection in the Surgical Treatment of Thyroid Cancer

The incidence of thyroid cancer is increasing, largely attributable to overdetection related to prevalent diagnostic and radiologic imaging modalities. Papillary thyroid cancer remains the most common thyroid malignancy. It has a high tendency for regional metastasis to the cervical lymph nodes. The optimal management of the neck in patients with thyroid carcinoma has long been an important topic of debate. This article addresses central and lateral neck dissection, providing a simplified guide to the most up-to-date and evidence-based practices.