Insignificance of prophylactic upper mediastinal lymph node dissection by sternotomy for papillary thyroid carcinoma

Investigating the Involvement of Mediastinal Lymph Nodes in Patients with Papillary Thyroid Carcinoma

Background

Papillary thyroid carcinoma (PTC) is also the most common endocrine malignancy. In the present study, we aimed to evaluate the metastasis pattern of upper mediastinal lymph node involvement in patients with PTC.

Materials and Methods

This is a descriptive cross-sectional study that was performed in 2020 in Isfahan, Iran, on 73 patients with PTC who were candidates for total thyroidectomy. Demographic data including age and gender were collected. The frequency distribution of upper mediastinal lymph node involvements and their relationships with mass size, gender, and age, location of tumor in the thyroid gland and involvement of lateral lymph nodes in the neck were evaluated.

Results

The mean mass size was 17.27 mm. The most involved thyroid lobe in patients with upper mediastinal lymph node involvement was the right lobe (16.5%). In terms of mediastinal lymph node involvement, there were no significant relationships between the two sexes (P = 0.161), primary mass size (P = 0.151), and thyroid mass location (P = 0.739) with mediastinal lymph node involvement. There was a significant relationship between lateral lymph node involvement of the neck (P = 0.007) and age groups (P = 0.042) with involvement of the upper mediastinal lymph nodes. Based on our results, the upper mediastinal lymph node involvement was more frequent among patients under 40 years of age.

Conclusion

Upper mediastinal lymph node metastasis in PTC was significantly more frequent in cases with younger ages (lower than 40 years) and involvements of lateral lymph nodes in the neck.

Surgical indications for upper mediastinal dissection by sternotomy in patients with papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is a relatively indolent disease, despite the high incidence of lymph node metastases. Although less frequent, some upper mediastinal metastases of PTC cannot be removed without sternal resection. In this study, we investigated the prognostic impact of upper mediastinal dissection (UMD) by sternotomy on patients with mediastinal metastases of PTC. Charts of patients with PTC who underwent surgical treatment at our institution between 2006 and 2018 were retrospectively reviewed. Fifty-eight patients with upper mediastinal metastases were enrolled. Kaplan-Meier survival curves were compared, and Cox hazard regression models were used for analyses. Of the 58 patients with mediastinal metastasis, 12 (20.7%) underwent dissection of the prevascular nodes, 51 (87.9%) underwent dissection of the upper paratracheal nodes, and 14 (24.1%) underwent dissection of the lower paratracheal node. The preferred site of mediastinal metastasis was the upper paratracheal nodes. The 5 and 10-year disease-specific survival rates for patients after UMD were 74.6% and 58.7%, respectively. Among 25 patients (43.1%) with locoregional recurrence, 12 (20.7%) had mediastinal recurrence and 7 were eligible for additional UMD. Although distant metastasis was the predominant poor prognostic factor, mediastinal recurrences were more frequently unresectable than cervical recurrences, suggesting that mediastinal recurrence is a poor prognostic factor. Mediastinal metastases larger than 30 mm or metastases to the lower paratracheal nodes are considered a risk factor for mediastinal recurrence. UMD by sternotomy for patient with upper mediastinal metastases which are difficult to resect via transcervical approach is an effective treatment option to improve patient prognosis.

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.

Mediastinal Lymph Node Metastases in Thyroid Cancer: Characteristics, Predictive Factors, and Prognosis

BACKGROUND

Mediastinal lymph node metastases (MLNM) have not been extensively studied. The aim of this study is to investigate the characteristics, predictive factors, and prognosis of MLNM in thyroid cancer.

METHODS

This is a retrospective study based on the thyroid cancer patients with MLNM at our institution from 2008 to 2015.

RESULTS

In total, 73 thyroid cancer patients with positive MLNM were included in this study. It contained sixty patients (82.2%) with papillary thyroid carcinoma (PTC), twelve (16.4%) with medullary thyroid carcinoma, and one (1.4%) with anaplastic thyroid carcinoma. Forty-eight patients had the surgery as initial treatment. Fifty-three (72.6%) patients remained disease-free, and fifteen (20.5%) developed a regional recurrence. Distant metastases occurred in four (5.5%) patients and five (6.8%) patients died. Five-year overall survival rate and disease-free survival (DFS) rate of the PTC patients for initial treatment are 95.4% and 77.2%, respectively. Extrathyroidal extension and multiple lymph nodes involved were associated with DFS in PTC patients.

CONCLUSIONS

Initial therapeutic control is very important for the thyroid cancer patients. Extrathyroidal extension and multiple mediastinal lymph nodes involved were the influence factors of prognosis in the thyroid cancer patients with MLNM.

Impact of superior mediastinal metastasis on the prognosis of papillary thyroid carcinoma

The impact of lymph node (LN) metastasis on survival or tumor recurrence in patients with papillary thyroid carcinoma (PTC) is controversial. The objective of this study was to investigate the effect of superior mediastinal metastasis on the prognosis of patients with PTC and to identify any correlations between such metastasis and clinical indicators. Medical records of PTC patients who underwent surgery as their initial treatment between 1981 and 2008 at our institution were retrospectively reviewed. Patients with or without superior mediastinal metastasis were selected. Prognosis was determined using the Kaplan-Meier method and Cox-hazard regression model with the forward stepwise method. Correlations between multiple factors and superior mediastinal metastasis were investigated using a binary logistic regression analysis. The study cohort included 488 patients of whom 75 (15.4%) had superior mediastinal metastasis. The survival differences between patients with superior mediastinal metastasis dissected via the transcervical approach and patients without metastasis were not significant. The prognosis of patients with superior mediastinal metastasis dissected by sternotomy was significantly poorer. As for disease-free survival, significant differences were found between patients with superior mediastinal metastases dissected by either method and patients without metastases. The main variables predicting superior mediastinal metastasis were an age of 45 years or older and the total number of cervical LN metastases. Superior mediastinal metastasis was an independent predictive factor for recurrence-free survival in PTC patients. The main variables predicting superior mediastinal metastasis were being 45 years of age or older, and having a greater total number of cervical LN metastases.