Usefulness of 1-year of thyroid stimulating hormone suppression on additional levothyroxine in patients who underwent hemithyroidectomy with papillary thyroid microcarcinoma

Is Maintaining Thyroid-Stimulating Hormone Effective in Patients Undergoing Thyroid Lobectomy for Low-Risk Differentiated Thyroid Cancer? A Systematic Review and Meta-Analysis

Simple Summary

In order to reduce the recurrence rate after surgical treatment of differentiated thyroid cancer (DTC), suppression of thyroid-stimulating hormone (TSH) or maintenance of a certain level after surgery are important. However, the effectiveness of TSH maintenance in the mid to lower reference range (0.5–2 mU/L) in patients undergoing thyroid lobectomy for low-risk DTC is uncertain. In this systematic review and meta-analysis, we compared and analyzed the recurrence rate according to whether TSH maintenance was performed in patients who underwent thyroid lobectomy for low-risk DTC. There was no difference in the recurrence rate with or without TSH control. Therefore, the recommendation to maintain TSH to reduce the recurrence rate after thyroid lobectomy is still controversial.

Abstract

There is no clear evidence that post-operative maintenance of thyroid-stimulating hormone (TSH) in the mid to lower reference range (0.5–2 mU/L) improves prognosis in patients undergoing thyroid lobectomy for low-risk differentiated thyroid cancer (DTC). The purpose of this systematic review and meta-analysis was to compare and analyze the recurrence rate according to whether the serum TSH level was maintained below 2 mU/L in patients who underwent thyroid lobectomy for low-risk DTC. Clinical data and outcomes were collected from MEDLINE, Embase, and the Cochrane Database of Systematic Reviews. The inclusion criteria were related studies on TSH maintenance or serum TSH concentration after surgery for DTC. Seven observational studies with a total of 3974 patients were included in this study. In the patients who received TSH maintenance less than 2 mU/L, the recurrence rate during the follow-up period was 2.3%. A subgroup analysis of five studies showed that the odds ratio for recurrence in patients who received TSH maintenance was 1.45 (p-value = 0.45) compared to patients who did not receive TSH maintenance. In conclusion, the evidence for the effectiveness of post-operative TSH maintenance less than 2 mU/L in patients undergoing thyroid lobectomy for low-risk DTC is insufficient.

Thyroid stimulating hormone suppression and recurrence after thyroid lobectomy for papillary thyroid carcinoma

BACKGROUND

Thyroid lobectomy is recommended as the primary treatment for low-risk thyroid cancer. However, recurrence and hypothyroidism may develop after lobectomy, necessitating thyroid hormone supplementation. The 2015 American Thyroid Association (ATA) guidelines recommended post-lobectomy thyroid-stimulating hormone (TSH) suppression. This study examined the need for TSH suppression and recurrence after lobectomy for unilateral papillary thyroid carcinoma (PTC).

METHODS

This study involved 369 patients who underwent thyroid lobectomy and ipsilateral central neck dissection for PTC between 2007 and 2015. Thyroid function tests were performed before and regularly after lobectomy. Binary logistic regression analyses were used to find factors predictive of the post-lobectomy need for TSH suppression that was defined by the 2015 ATA guidelines.

RESULTS

Serum TSH concentrations gradually increased after lobectomy: proportions with TSH >2 mIU/L at post-lobectomy 1, 3-6, 12, and 24 months were found in 77.0%, 82.3%, 66.7%, and 59.9%, respectively. After lobectomy, 168 (45.5%) patients received levothyroxine (T4) supplementation. Multivariate logistic regression analyses showed that pre-TSH level >2 mIU/L was the sole independent variable predictive of the need for post-lobectomy TSH suppression (P = 0.003). During the median follow-up of 72 months, recurrence was found in 4 (1.1%) patients who never received T4 supplementation and had post-lobectomy TSH levels >2 mIU/L.

CONCLUSIONS

Our data show that thyroid lobectomy for unilateral PTC is associated with a low recurrence rate, but a significant risk of hypothyroidism. Preoperative TSH level can predict the need for post-lobectomy TSH suppression compliant with the 2015 ATA guidelines.

Potential protection of indocyanine green on parathyroid gland function during near-infrared laparoscopic-assisted thyroidectomy: A case report and literature review

BACKGROUND

In recent decades, significant advances have been made in protecting the parathyroid glands and recurrent laryngeal nerves during thyro-idectomy. However, reliable and convenient technical means are still lacking. In this study, the reliability, safety and feasibility of near-infrared (NIR) laparoscopy-assisted thyroid lobectomy with isthmectomy and prophylactic central lymph node dissection (CLND) were reported.

CASE SUMMARY

A 63-year-old female patient with a free previous medical history, was admitted to our department due to multiple thyroid nodules. Ultrasonic examination suggested diffuse thyroid changes and one thyroid nodule in the right upper lobe with the largest diameter of 1.5 cm adjacent to the trachea and Breast Imaging Reporting and Data System grade 4B. Imaging examination of the neck showed no obvious enlarged lymph nodes. Fine needle aspiration biopsy suggested a papillary thyroid carcinoma. Combined with thyroid function examination, the patient was diagnosed with papillary thyroid carcinoma and Hashimoto's thyroiditis. Considering the risk of invading the capsule and the patient's extreme anxiety, a right thyroid lobectomy with isthmectomy and prophylactic CLND was planned. No significant abnormalities were found during preoperative examinations, except for an increased thyroid stimulating hormone level. The patient underwent NIR laparoscopy-assisted thyroid lobectomy with isthmectomy and prophylactic CLND. During the operation, two right parathyroid glands (PGs) adjacent to the thyroid gland capsule and the right recurrent laryngeal nerve (RLN) were examined by indocyanine green (ICG) fluorescence using a NIR fluorescence camera, and the PGs and RLN were reliably preserved. Considering the ICG-positive PG, prophylactic CLND was performed. The postoperative parathyroid hormone level was in the normal range and no significant hypocalcemia symptoms were observed.

CONCLUSION

During NIR laparoscopy-assisted thyroidectomy, ICG fluorescence may aid PG identification and protection.

Prediction of level V metastases in papillary thyroid microcarcinoma: a single center analysis

Background

The rate of level V metastases is significantly low and the necessity of routine level V dissection for papillary thyroid microcarcinoma (PTMC) with clinically lateral lymph node metastasis (LNM) is still controversial.

Methods

This study enrolled 114 consecutive PTMC patients with clinically suspected lateral LNM (N1b) who underwent modified radical neck dissection (levels II to V) at Xiangya Hospital of Central South University from September 2016 to July 2019. Univariate and multivariate analyses were performed to investigate the predictive factors of level V metastasis. The area under the receiver operating characteristic (ROC) curve (AUC), accuracy, specificity and sensitivity were used to determine the predictive value.

Results

The overall and occult rate of level V metastasis were 29.82% (34/114) and 7.02% (8/114), respectively. Univariate analysis showed that level V metastasis was significantly associated with gross extrathyroidal extension (ETE), level IV metastasis and 2-level simultaneous metastasis (all P<0.05). Gross ETE (OR =11.916, 95% CI, 1.404-102.19; P=0.023) and level IV metastasis (OR =8.497, 95% CI, 2.119-34.065; P =0.03) served as independent predictors of level V metastasis in N1b PTMC patients. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of gross ETE and level IV metastasis in predicting the level V metastasis were 25.3% vs. 82.4%, 97.5% vs. 73.8%, 82.69% vs. 76.32%, 80% vs. 57.04% and 75% vs. 90.77%, respectively. The AUC of gross ETE was lower than level IV metastasis (0.605 vs. 0.781, P=0.041).

Conclusions

Routine level V dissection is necessary in N1b PTMC patients with level IV metastasis or gross ETE. Compared with gross ETE, level IV metastasis is superior in predicting level V metastasis.

Predicting factors of central lymph node metastases in patients with unilateral multifocal papillary thyroid microcarcinoma

Background

Unilateral multifocal papillary thyroid microcarcinoma (UM-PTMC) is not rare, and the suitable extent of operation is controversial. Total thyroidectomy is associated with a high risk of hypoparathyroidism and recurrent laryngeal nerve injury. Hemithyroidectomy should be considered in patients without lymph node metastases. This study aimed to identify factors predicting central lymph node metastases (CLNM) in patients with UM-PTMC.

Methods

A total of 1,453 patients with thyroid cancer underwent surgery at our hospital from January 2018 to June 2018, and 115 patients with UM-PTMC were selected and assessed retrospectively. The relationship between CLNM and clinicopathologic features of UM-PTMC were analyzed by both univariate and multivariate analyses.

Results

Of the 115 patients with UM-PTMC, CLNM were confirmed by pathology in 57 patients. Univariate and multivariate analyses identified the sum diameter of all tumors (≥1.0 cm) [odds ratio (OR) =2.295; 95% confidence interval (CI): 1.036-5.086; P=0.041] and positive CLNM via ultrasonography (OR =5.882; 95% CI: 1.562-22.153; P=0.009) as independent predictors of CLNM.

Conclusions

CLNM are common in patients with UM-PTMC. The sum diameter of all tumors (≥1.0 cm) and positive CLNM via ultrasonography are independent risk factors for CLNM. Our data should be considered in the decision process relating to performing total thyroidectomy or hemithyroidectomy in patients with UM-PTMC.