Management of the locally aggressive thyroid carcinoma

Role of Matrix Metalloproteinases and Their Inhibitors in Locally Invasive Papillary Thyroid Cancer

Locally invasive papillary thyroid carcinoma (PTC) protrudes beyond the thyroid capsule and invades local structures. Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) are implicated in local invasion and metastasis in PTC. The aim of our study was to determine expression levels of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 in tissue specimens of invasive and non-invasive PTC. Our hypothesis was that expression levels of these biomarkers correlate with the development of locally invasive PTC. In our single-center study we retrospectively investigated MMP and TIMP expression levels in 50 samples of thyroid tissue diagnosed as locally invasive papillary carcinoma (study group) and 30 samples of thyroid tissue diagnosed as non-invasive, non-metastatic papillary carcinoma (control group). Tissue specimens were immunohistochemically stained with primary monoclonal antibodies against MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2. When correlating expression levels of MMPs and TIMPs in thyroid tissue, statistically significant differences were found for MMP-1 and TIMP-1 expression (p < 0.001; Mann−Whitney U test) with the highest levels of expression in the invasive PTC group. Although expression of MMP-9 and TIMP-2 was higher in invasive PTC, the differences were not statistically significant. Elevated expression of MMP-1 and TIMP-1 in tumor tissue can predict invasiveness for PTC.

Locally advanced asymptomatic papillary thyroid cancer presenting with retropharyngeal lymph node metastasis symptoms

Papillary thyroid cancer (PTC) rarely metastasizes to the retropharyngeal lymph nodes. Managing patients with locally advanced primary PTC and metastasis located in distant anatomical areas is challenging. Herein, we report a 56-year-old patient with locally advanced asymptomatic PTC, who presented with obstructive airway symptoms due to the metastatic retropharyngeal lymph node. The patient underwent simultaneous total thyroidectomy, central lymph node dissection, en bloc resection of strap muscle and left laryngeal nerve via cervical approach and transoral resection of the metastatic retropharyngeal lymph node. Metastatic PTC should be included in the differential diagnosis of a retropharyngeal masses. Simultaneous total thyroidectomy of the primary thyroid cancer via a cervical approach and transoral resection of an isolated retropharyngeal metastasis is safe and feasible.

True Vocal Fold Immobility in the Setting of Well-Differentiated Thyroid Carcinoma: Unusual Illustrative Cases and Recommendations for Operative Strategy

Objectives:

We present cases of transient true vocal fold (TVF) immobility caused by well-differentiated thyroid carcinoma (WDTC), and review the literature concerning management of WDTC invading the recurrent laryngeal nerve (RLN).

Methods:

A description of the clinical course of 2 patients with WDTC and transient TVF immobility is presented in the context of a review of the literature concerning locally advanced WDTC with extrathyroidal extension and RLN involvement.

Results:

Both patients had papillary thyroid carcinoma with ipsilateral TVF paralysis that resolved completely before operation. During the operation, the RLN was found to be grossly involved with disease and inseparable from the tumor, necessitating resection. Review of the literature revealed the following points that should be considered when confronting an RLN invaded by WDTC. 1) Benign disease can mimic invasive WDTC and must be ruled out. 2) RLN invasion does not carry the same prognostic implications as other categories of extrathyroidal extension of WDTC. 3) RLN sacrifice does not increase the overall survival rate. 4) There is no evidence that a paralyzed RLN will regain function when preserved. 5) The majority of RLNs that function before operation can be expected to function after the operation if preserved.

Conclusions:

Resolution of TVF paralysis should not reduce suspicion of RLN involvement by WDTC. When RLN involvement is discovered during operation, every attempt should be made to preserve a functioning RLN.

Expression of MMP-1 in invasive well-differentiated thyroid carcinoma

The objective of this study is to examine the expression of matrix metalloproteinase 1 (MMP-1) in invasive well-differentiated thyroid carcinoma (WDTC) and its relation to clinicopathological features. This retrospective case study group included 26 patients with invasive WDTC who were treated at our center between January 1985 and May 2007. Clinical data were collected from the medical files. MMP-1 expression was tested in samples from paraffin-embedded tumor by immunohistochemical staining. MMP-1 expression correlated with laryngotracheal invasion (p = 0.032), multifocality of the tumor (p = 0.044), and presence of regional (p = 0.034) and distant metastases (p = 0.048). In conclusion, the expression of MMP-1 in invasive WDTC is consistent with tumor aggressiveness, manifested by laryngotracheal invasion, multifocality, and regional and distant metastases. MMP-1 expression may serve as a prognostic marker and an indicator for the need for more aggressive surgical treatment.

Changes in surgical anatomy following thyroidectomy

Thyroid reoperation is known to carry a higher risk for complications because of the increased challenge of identifying tissue planes, presence of adherent strap muscles, and generalized scarring of the thyroid bed. Consideration of postsurgical changes in the anatomy of important landmarks, such as the recurrent and superior laryngeal nerves, brachiocephalic artery, and parathyroid glands, is crucial during preoperative planning for thyroid reoperations. This article provides a review of these key changes in surgical anatomy and the implications of the anatomic changes after thyroidectomy.

Thyroid cancer invasion of neck structures: epidemiology, evaluation, staging and management

PURPOSE OF REVIEW

This review addresses the issue of direct extra-capsular invasion of thyroid cancer; this may occur in several ways and to varying degrees. The evidence regarding the prognostic and treatment implications of extra-thyroidal spread is examined. The phenomenon is most common in papillary carcinoma of the thyroid and that is the focus for this review. Less common, but more aggressive tumours (medullary and anaplastic carcinoma) are not considered here.

RECENT FINDINGS

Overall, around 15% of thyroid cancers exhibit extra-thyroid spread but the rate is much higher in specific subgroups. The presence of invasive disease affects the staging of the tumour, and the implications for surgery can be substantial if complete tumour extirpation is to be achieved. No particular examination is completely accurate in detecting extra-thyroid spread preoperatively. Invasion posteriorly carries greater morbidity and mortality than anterior spread. The presence of extra-thyroid spread usually warrants adjuvant radiotherapy (radioiodine or external beam).

SUMMARY

Histologic assessment is the gold standard for detecting invasive thyroid cancer. Thyroidectomy is effectively a staging procedure by which the presence and extent of invasive disease can be established and subsequent management determined. Extra-thyroidal spread influences morbidity and mortality.