Surgery for patients with thyroid carcinoma invading the trachea: circumferential sleeve resection followed by end-to-end anastomosis

Surgical strategy of locally advanced differentiated thyroid cancer

Approximately 20% of patients with differentiated thyroid cancer (DTC) have direct tumor extension with invasion of the surrounding tissues such as the larynx, trachea, esophagus, or recurrent laryngeal nerve. Recent progress of molecular-targeted therapy, such as the use of tyrosine kinase inhibitors, improves survival outcome in patients with advanced DTC. However, induction of tyrosine kinase inhibitors for locally-advanced DTC has presented novel fatal adverse events including fistula in patients with infiltration toward to the trachea, pharynx and esophagus, and fatal bleeding in patients with great vessel invasion. Surgery therefore still has an important role in DTC management, particularly in local control. The surgical strategy for laryngeal/tracheal invasion, which commonly occurs by DTC, is decided according to the extension (depths and area) of the tumor. The "shave procedure" is performed when the tumor has superficially invaded the larynx/trachea. However, intra-luminal extension requires resection and reconstruction of the larynx/trachea wall. Large veins, such as the internal jugular vein and the subclavian vein, are also frequently directly invaded by DTC. Three types of jugular vein reconstruction have been advocated to avoid fatal complications according to bilateral jugular vein ligation. The majority of carotid artery invasion by DTC can be managed with tumor resection of the sub-adventitial layer without reconstruction surgery using an artificial vessel. In this review article, we examine surgery for advanced DTC, showing the surgical strategy toward DTC that has invaded the laryngotracheal, recurrent laryngeal nerve, esophagus/hypopharynx, or great vessels.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

Circumferential Laryngotracheal Resection in Thyroid Cancer: Experience and Outcome in a Single Center

There is limited experience of laryngotracheal resection in patients with differentiated thyroid carcinoma (DTC). The aim of this study was to report our experience of circumferential laryngotracheal resection in DTC and its long-term outcome. In this retrospective study, 10 patients of locally invasive DTC who underwent circumferential laryngotracheal resection between January 2000 and December 2015 were included. Clinicopathologic profile and follow up was noted. Mean age of the cohort was 50.1 ± 7.8 years (M:F = 1: 2.3). Papillary carcinoma was the commonest pathology (60%) followed by follicular carcinoma (20%), 10% each had Hurthle cell and poorly differentiated thyroid carcinoma. Sixty percent patients presented with recurrent or persistent disease and 20% with distant metastases. Vocal cord palsy was observed in 30%. Fifty percent patients underwent tracheal resection with end to end anastomosis and remaining laryngotracheal resection. Carotid artery resection and anastomosis was performed in one patient. Shin stage IV invasion was observed in 80% and stage III in remaining. There was no perioperative mortality. All patients received adjuvant radioiodine therapy and 40% external beam radiotherapy. Median follow up was 48 months. One patient who earlier had tracheal resection underwent total laryngectomy due to recurrent disease after 24 months. Forty percent patients developed distant metastases during follow-up. Mean survival was 77.8 months (CI = 63.0-92.5). Five-year overall survival was 60% and was significantly high in those without distant metastases (p = 0.006). The outcome of circumferential larygotracheal resections for DTC is excellent in terms of local disease control and long term survival.

Haemoptysis: An Uncommon Presentation in an Incidental Thyroid Nodule-A Case Report

Thyroid cancers invading the critical structures like trachea, oesophagus, recurrent laryngeal nerve and major vessels are uncommon. Even though uncommon, patients with large thyroid lesion (> 4 cm) or aggressive histology can present with features of invasion. Careful evaluation and appropriate surgical management is needed for optimal outcome. This case is presented to make our otolaryngology-head and neck surgeons aware of such unique situation where an incidental thyroid nodule presenting as haemoptysis due to tracheal invasion.

Surgery for Thyroid Cancer Invading the Trachea

Thyroid cancer invading the trachea can be asymptomatic, but when tumour invasion reaches the mucosal surface, it causes bloody sputum and dyspnoea. The treatment plan for thyroid cancer is determined based on the site, depth, and extent of the invasion. Different from tumours arising from the tracheal mucosa, in thyroid cancer, invasion begins outside the airway and progresses toward the lumen, making it difficult to accurately diagnose the extent of the invasion even with bronchoscopy. Therefore, surgeons must determine the range of resection during surgery. Invasion reaching the tracheal mucosa requires full-thickness resection and is performed using tracheal window resection combined with tracheocutaneous fistula or tracheal sleeve resection followed by end-to-end anastomosis. The airway is safely secured with window resection, but closing the tracheal stoma often requires multi-stage reconstruction. Sleeve resection is an oncologically appropriate surgical method that can be completed in one stage, although there is a risk of serious complications associated with anastomotic dehiscence. Since well-differentiated thyroid cancer progresses slowly, some degree of survival can be expected even with incomplete resection. However, when shaving is performed for tumours with deep invasion that reaches the tracheal mucosa, the residual tumour tissue continues to grow steadily and eventually leads to airway stenosis. Since reoperation for tracheal resection is difficult, radical full-thickness resection should be performed in the initial surgery. Although this surgical intervention is far more demanding for both patients and surgeons than shaving, the procedure eventually improves patient's prognosis and quality of life.

Laryngotracheal Resection in Thyroid Cancer - Experience from a Single Centre Series of 22 Cases

Involvement of the aerodigestive tract is reported in one-third of patients with locally invasive thyroid cancer. It is associated with significant morbidity and mortality, with airway obstruction being the immediate cause of death in 50% of patients who die of thyroid cancer. Management is challenging and includes the risks of extensive surgery as well as decisions regarding the type of surgery and adjuvant therapy. Retrospective cohort study, reporting institutional experience with patients who underwent laryngotracheal resection for invasive thyroid cancer over the past 10 years. Twenty-two patients were included in the study. All patients had Shin stage 4 disease. The median follow-up was 18 months. Five patients had systemic metastasis at diagnosis. Nineteen patients underwent tracheal resection and end to end anastomosis, and 3 underwent laryngectomy. The mean length of the resected trachea was 2.94 cm. Tracheal releasing manoeuvres were utilized in 11 patients. Three patients required a tracheostomy postoperatively. Other complications included a temporary vocal cord palsy in 5 patients, temporary hypocalcemia in 6 and permanent hypocalcemia in 1 patient. Adjuvant radiotherapy was utilized in 9 patients and I-131 therapy in 13 patients. Three patients died during follow-up. Two patients developed thyroid bed recurrence, two patients developed systemic metastasis on follow-up. Most patients survived for a prolonged period with only biochemical evidence of disease persistence and three with no evidence of disease. Laryngotracheal resection with primary anastomosis is a safe and effective option, providing adequate symptomatic relief as well as prolonged survival in carefully selected patients with invasive Shin stage 4 disease.

Tracheal and Cricotracheal Resection With End-to-End Anastomosis for Locally Advanced Thyroid Cancer: A Systematic Review of the Literature on 656 Patients

Airway involvement by advanced thyroid carcinoma (TC) constitutes a negative prognosticator, besides being a critical clinical issue since it represents one of the most frequent causes of death in locally advanced disease. It is generally agreed that, for appropriate laryngo-tracheal patterns of invasion, (crico-)tracheal resection and primary anastomosis [(C)TRA] is the preferred surgical technique in this clinical scenario. However, the results of long-term outcomes of (C)TRA are scarce in the literature, due to the rarity of such cases. The relative paucity of data prompts careful review of the available relevant series in order to critically evaluate this surgical technique from the oncologic and functional points of view. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement on the PubMed, Scopus, and Web of Science databases. English-language surgical series published between January 1985 and August 2021, reporting data on ≥5 patients treated for TC infiltrating the airway by (C)TRA were included. Oncologic outcomes, mortality, complications, and tracheotomy-dependency rates were assessed. Pooled proportion estimates were elaborated for each end-point. Thirty-seven studies were included, encompassing a total of 656 patients. Pooled risk of perioperative mortality was 2.0%. Surgical complications were reported in 27.0% of patients, with uni- or bilateral recurrent laryngeal nerve palsy being the most common. Permanent tracheotomy was required in 4.0% of patients. Oncologic outcomes varied among different series with 5- and 10-year overall survival rates ranging from 61% to 100% and 42.1% to 78.1%, respectively. Five- and 10-year disease specific survival rates ranged from 75.8% to 90% and 54.5% to 62.9%, respectively. Therefore, locally advanced TC with airway invasion treated with (C)TRA provides acceptable oncologic outcomes associated with a low permanent tracheotomy rate. The reported incidence of complications, however, indicates the need for judicious patient selection, meticulous surgical technique, and careful postoperative management.

Surgical Management of Tracheal Invasion by Well-Differentiated Thyroid Cancer

Simple Summary

Tracheal invasion is a poor prognostic factor in well-differentiated thyroid cancer. Appropriate resection can improve the prognosis and maintain the patient’s quality of life. Shaving resection for superficial tracheal invasion is minimally invasive because it does not involve the tracheal lumen, despite the problematic risk of local recurrence. Window resection for tracheal mucosal and luminal invasion provides good tumor control and does not cause postoperative airway obstruction; however, the need for surgical closure of the tracheocutaneous fistula is a disadvantage of this method. Circumferential (sleeve) resection and end-to-end anastomosis are highly curative, but the risk of fatal complications, such as anastomosis dehiscence, is a concern.

Abstract

Well-differentiated thyroid carcinoma (WDTC) is a slow-growing cancer with a good prognosis, but may show extraglandular progression involving the invasion of tumor-adjacent tissues, such as the trachea, esophagus, and recurrent laryngeal nerve. Tracheal invasion by WDTC is infrequent. Since this condition is rare, relevant high-level evidence about it is lacking. Tracheal invasion by a WDTC has a negative impact on survival, with intraluminal tumor development constituting a worse prognostic factor than superficial tracheal invasion. In WDTC, curative resection is often feasible with a small safety margin, and complete resection can ensure a good prognosis. Despite its resectability, accurate knowledge of the tracheal and peritracheal anatomy and proper selection of surgical techniques are essential for complete resection. However, there is no standard guideline on surgical indications and the recommended procedure in trachea-invading WDTC. This review discusses the indications for radical resection and the three currently available major resection methods: shaving, window resection, and sleeve resection with end-to-end anastomosis. The review shows that the decision for radical resection should be based on the patient’s general condition, tumor status, expected survival duration, and the treating facility’s strengths and weaknesses.

Long-term outcomes of differentiated thyroid cancers with tracheal invasion: A 15-year experience

BACKGROUND

Tracheal invasion is reported to occur in approximately one-third of the patients of locally advanced thyroid cancers. There is a paucity of data in literature with regard to the long-term outcomes of thyroid cancers with tracheal invasion.

METHODS

A total of 37 patients from our tertiary care center underwent radical surgery for tracheal involvement for differentiated thyroid cancers between the years 2002 and 2016. The variables pertaining to the demographics, clinical presentation, imaging, operative details and histopathology reports were captured from the patient's case records and analyzed.

RESULTS

Among the 37 patients, there were 21 males and 16 females. Majority of the patients (56.8%) were >55 years of age. Surgery (tracheal resection) was performed in the primary setting in 29 patients, whereas it was performed in a recurrent setting in 8 patients. As per the Shin classification, 3 patients belonged to Shin stage 1, 3 to Shin stage 2, 16 patients to Shin stage 3 and 15 patients to Shin stage 4. There was no 30 day postoperative mortality in our cohort. The median follow-up of our cohort was 175 months. The 5-, 10-, and the 15-year overall survivals of the entire cohort were 81.7%, 47.8%, and 35.9%, respectively.

CONCLUSION

Our series shows favorable long-term oncological outcomes of selected patients of thyroid cancers with tracheal resection and adds to the limited long-term data available in literature.

Tracheal Resection in the Management of Thyroid Cancer: An Evidence-Based Approach

OBJECTIVE

Determine the effect of patient demographics and surgical approach on patient outcomes after tracheal resection in the management of thyroid cancer.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Systematic review of literature was performed using PubMed, Embase, and Cochrane Library to identify patients with thyroid carcinoma who underwent tracheal resection. Pooled estimates for patient demographics, presenting findings, complications, and outcomes are determined using random-effects meta-analyses.

RESULTS

Ninety-six relevant studies encompassing 1,179 patients met inclusion criteria. Meta-analysis pooled rates of complications: 1.7% (confidence interval [CI] 0.8-2.5; P < .001; I² = 1.85%) airway complications, 2.8% (CI 1.6-3.9; P < .001; I² = 13.34%) bilateral recurrent laryngeal nerve paralysis, 2.2% (CI 1.2-3.1; P < .001; I² = 6.72%) anastomotic dehiscence. Circumferential resection pooled estimates major complications, locoregional recurrence, distal recurrence, overall survival: 14.1% (CI 8.3-19.9; P < .001; I² = 35.26%), 15% (CI 9.6-20.3; P < .001; I² = 38.2%), 19.7% (CI 13.7-25.8; P < .001; I² = 28.83%), 74.5% (CI 64.4-84.6; P < .001; I² = 85.07%). Window resection estimates: 19.8% (CI 6.9-32.8; P < .001; I² = 18.83%) major complications, 25.6% (CI 5.1-46.1; P < .014; I² = 84.68%) locoregional recurrence, 15.6% (CI 9.7-21.5; P < .001; I² = 0%) distal recurrence, 77.1% (CI 58-96.2; P < .001; I² = 78.77%) overall survival.

CONCLUSION

Management of invasive thyroid carcinoma may require tracheal resection to achieve locoregional control. Nevertheless, postoperative complications are not insignificant, and therefore this risk cannot be overlooked when counseling patients perioperatively. Laryngoscope, 131:932-946, 2021.

Surgical treatment of locally advanced thyroid cancer

Operations in this area are demanding and require special experience in endocrine, thoracic and vascular surgery, an experienced anaesthesiologist, as well as the interdisciplinary cooperation with other medical specialists (nuclear medicine, oncology, radiology, otolaryngology). A reliable system of surgical guidelines has been developed from a few individual publications with special impact.

The revised clinical practice guidelines on the management of thyroid tumors by the Japan Associations of Endocrine Surgeons: Core questions and recommendations for treatments of thyroid cancer

The Japan Associations of Endocrine Surgeons has developed the revised version of the Clinical Practice Guidelines for Thyroid Tumors. This article describes the guidelines translated into English for the 35 clinical questions relevant to the therapeutic management of thyroid cancers. The objective of the guidelines is to improve health-related outcomes in patients with thyroid tumors by enabling users to make their practice evidence-based and by minimizing any variations in clinical practice due to gaps in evidential knowledge among physicians. The guidelines give representative flow-charts on the management of papillary, follicular, medullary, and anaplastic thyroid carcinoma, along with recommendations for clinical questions by presenting evidence on the relevant outcomes including benefits, risks, and health conditions from patients' perspective. Therapeutic actions were recommended or not recommended either strongly (◎◎◎ or XXX) based on good evidence (😊)/good expert consensus (+++), or weakly (◎, ◎◎ or X, XX) based on poor evidence (😣)/poor expert consensus (+ or ++). Only 10 of the 51 recommendations given in the guidelines were supported by good evidence, whereas 35 were supported by good expert consensus. While implementing the current guidelines would be of help to achieve the objective, we need further clinical research to make our shared decision making to be more evidence-based.

Solitary fibrous tumor of the trachea: a case report

We experienced a surgical case of a rare primary tracheal tumor. A 77-year-old woman visited a local clinic with chief complaints of coughing, wheezing, and discomfort in the throat. Computed tomography revealed a mass measuring approximately 1.5 cm in the mediastinal trachea, extending from the membranous portion of the trachea to the esophagus. Bronchofibroscopy showed a flat, smooth-surfaced, round mass arising from the membranous portion. Surgery was performed because of the possibility of airway obstruction and suffocation. Sleeve resection of five tracheal rings was performed via median sternotomy and interrupted suture was performed using 3-0 absorbable suture material. The postoperative course was favorable and there has been no evidence of recurrence. The pathological diagnosis was solitary fibrous tumor. A primary solitary fibrous tumor of the trachea is extremely rare. Here, we report this disease with a literature review.

The Healing Effect of Platelet-rich Plasma (PRP) Jelly in Rabbits Undergoing Tracheal Resection and Anastomosis

BACKGROUND/AIM

Tracheal anastomosis is commonly indicated for patients with tracheal tumor, stenosis and tracheoesophageal fistula. This study was designed to evaluate the healing activity of topical application of platelet-rich plasma (PRP) jelly for tracheal reconstruction in a rabbit model.

MATERIALS AND METHODS

Thirty-six healthy New Zealand White rabbits were assigned to three groups of 12 animals each. The control group underwent tracheal resection and anastomosis. The fibrin-glue group and PRP-jelly group underwent tracheal resection and anastomosis plus fibrin glue or PRP jelly application over the anastomosis and surgical field, respectively.

RESULTS

The PRP jelly treatment enhanced the healing capacity by positive effects on healing rate, tissue fill, and volume fraction of fibroblasts during the 28 days following surgery.

CONCLUSION

Application of PRP jelly to tracheal anastomotic wounds can accelerate or improve the quality of repair.

Complications from tracheal resection for thyroid carcinoma

Thyroidectomy associated to en bloc tracheal resection with end-to-end anastomosis is the treatment of choice of thyroid tumor invading the tracheal wall and is associated with a good prognosis. However, the postoperative morbidity is not irrelevant. The present review aims to discuss the complications occurring after this aggressive surgical procedure. The search was performed using PubMed through an overarching for the following terms: "complication of tracheal resection [AND] invasive thyroid cancer". Postoperative complications rate after tracheal sleeve resection with end-to-end anastomosis for thyroid cancer invading tracheal wall range from 15% to 39%. Postoperative mortality is about 1.2%. The most common postoperative complications are: anastomotic dehiscence, airway stenosis, infections and bleeding. Tumor local recurrence can be considered a late on set complication. To conclude, in locally invasive thyroid cancer, en bloc resection of the thyroid with the tracheal segment interested by the tumor provides a good prognosis despite the non-negligible postoperative morbidity rate. Patients' selection and accurate surgical technique performing a tracheal tension-free anastomosis are mandatory to reduce postoperative morbidity and mortality.

Tracheal and Crico-Tracheal Resection and Anastomosis for Malignancies Involving the Thyroid Gland and the Airway

Objectives:

To evaluate outcomes in different malignancies involving the thyroid and infiltrating the airway submitted to tracheal (TRA) or crico-tracheal resection and anastomosis (CTRA).

Methods:

Retrospective charts review of 27 patients affected by thyroid malignancies involving the airway treated by TRA/CTRA in a single academic institution. Kaplan-Meier curves were used to evaluate the overall (OS) and disease-specific (DSS) survivals and local (LC) and loco-regional control (LRC). Impact on survival of age, comorbidities, previous radiotherapy, types of TRA/CTRA, Shin’s stage (II, III, IV), grading (well vs poorly differentiated), and length of airway resected was calculated by the log-rank test.

Results:

Overall survival and DSS at 3 and 5 years were 82.3% and 71.6%, respectively. Local control and LRC in the entire group were 82.3% at 3 and 5 years. Crico-tracheal resection and anastomosis involving the cricoid arch and plate (type C) and tumor differentiation significantly affected OS and DSS (both P < .001). Type C CTRA and tumor differentiation significantly impacted on LC ( P = .002 and P = .009, respectively).

Conclusions:

Grading and extension of CTRA to the cricoid plate are the most important factors for oncologic outcomes in thyroid malignancies infiltrating the airway. Except for poorly differentiated tumors, TRA/CTRA allows adequate LC even in advanced stage lesions involving the crico-tracheal junction.

Surgical Management of Cricotracheal Invasion by Papillary Thyroid Carcinoma

BACKGROUND

In general, patients with papillary thyroid carcinoma (PTC) have an excellent postoperative prognosis. Those with cricoid and/or tracheal PTC invasion, however, are at a higher risk of postoperative morbidity and airway insufficiency.

METHODS

We investigated postoperative airway outcomes, locoregional recurrence, and survival rates in patients with PTC who underwent cricotracheal resection. The records of PTC patients who underwent surgery at our institution between 1981 and 2009 were reviewed retrospectively, and 110 patients with cricotracheal invasion were enrolled. Curative resection was performed in all patients, and cricotracheal function was preserved or reconstructed when possible.

RESULTS

Of the 110 patients, 57 and 53 patients had superficial and intraluminal invasion of the larynx, respectively. After the initial surgery, the 10-year disease-specific survival rates were 90.8 and 44.4 % in patients with superficial and intraluminal invasion of the cricotracheal area, respectively. Only six patients (5.5 %) had an isolated upper aerodigestive tract recurrence. Five patients were managed with an additional window resection as salvage surgery. Consequently, only one patient (0.9 %) underwent total laryngectomy. Altogether, 31 patients (28.0 %) had a permanent stoma, 9 and 15 of which were caused by cricotracheal invasion and invasion of other aerodigestive structures, respectively.

CONCLUSIONS

Window resection for intraluminal cricotracheal invasion by PTC produced good surgical outcomes that resulted in a low local recurrence rate and survival rates that resembled those associated with other surgical treatments. Treatment of multiple organ invasion of the aerodigestive tract was necessary to improve postoperative functional outcomes in these patients.

Management of invasive well-differentiated thyroid cancer: an American Head and Neck Society consensus statement. AHNS consensus statement

BACKGROUND

Invasive differentiated thyroid cancer (DTC) is relatively frequent, yet there is a paucity of specific guidelines devoted to its management. The Endocrine Committee of the American Head and Neck Society (AHNS) convened a panel to provide clinical consensus statements based on review of the literature, synthesized with the expert opinion of the group.

METHODS

An expert panel, selected from membership of the AHNS, constructed the manuscript and recommendations for management of DTC with invasion of recurrent laryngeal nerve, trachea, esophagus, larynx, and major vessels based on current best evidence. A Modified Delphi survey was then constructed by another expert panelist utilizing 9 anchor points, 1 = strongly disagree to 9 = strongly agree. Results of the survey were utilized to determine which statements achieved consensus, near-consensus, or non-consensus.

RESULTS

After endorsement by the AHNS Endocrine Committee and Quality of Care Committee, it received final approval from the AHNS Council.

New technology applications: Knotless barbed suture for tracheal resection anastomosis

OBJECTIVES/HYPOTHESIS

Tracheal resection anastomoses are often under tension and can be technically challenging. New suture materials such as V-loc (barbed, knotless wound closure device) may offer advantages over conventional methods. The objective of this study is to determine if a running V-loc suture is of comparable tensile strength to conventional closure.

STUDY DESIGN

Laboratory based study of human cadaveric tissue.

METHODS

Fresh human cadaveric tracheas were dissected and incised into segments. Anastomosis of adjacent segments was then performed with either submucosal interrupted 3-0 Vicryl, or a running submucosal 3-0 V-loc suture. Anastomosed specimens were stretched to failure on an Instron force tension machine. Surgeon satisfaction was recorded by visual analog scale (VAS).

RESULTS

The tensile strength of 12 tracheal anastomoses was tested. Video documentation of V-loc suture technique and anastomosis failure was recorded. In both Vicryl (80%) and V-loc (100%) anastomoses, failure occurred at the membranous intercartilaginous region. In 20% of the Vicryl anastomoses, the suture was noted to break prior to tissue failure. Anastomoses with V-loc suture had equivalent failure force (mean, 59 N) compared to interrupted Vicryl (51 N), with P = .57. On VAS, surgeons were more satisfied with V-loc suture closure compared to interrupted Vicryl closure (paired t test, P = .003).

CONCLUSIONS

Tracheal anastomosis with running v-loc suture is a feasible alternative to conventional closure with interrupted Vicryl suture. V-loc suture provided a surgical advantage by improved ease of use.

[Extrathyroidal thyroid cancer : results of tracheal shaving and tracheal resection]

Extrathyroidal thyroid cancer invading the laryngotracheal system (UICC stage pT4a) represents a progressive process of infiltration of the tracheal wall layers from the outer to the inner parts of the trachea. These tumors usually present with high proliferation activity correlating with a reduced long-term prognosis. In contrast to intraluminal manifestation requiring complete wall resection, in cases of non-transmural invasion, complete tumor removal can be sometimes achieved by extraluminal tangential resection (shaving). Tangential resections, however, are associated with a higher frequency of microscopically invaded resection margins (R1 resection rate >40%). The available comparative studies (all retrospective, maximum EBM level 3) analyzing oncological outcome show inconsistent results. In more recently published studies, however, complete wall resection in well-differentiated thyroid cancer with tracheal invasion only was found to be associated with longer recurrence-free and tumor-specific survival when compared to shaving. Deep larynx invasion is associated with reduced long-term prognosis when compared to invasion of the trachea. Salvage resections should therefore be performed in selected cases only.

Prognosis and management of invasive well-differentiated thyroid cancer

Invasive thyroid cancer is often asymptomatic and can take the surgeon and the patient by surprise. Maintenance of a high level of suspicion in patients who present with symptoms, an abnormal examination, recurrent disease, or documented metastatic disease lead the clinician to obtain appropriate cross-sectional imaging that helps to define the full extent of the disease. Specific guidelines are provided for the management of the various structures in the neck that are at risk for involvement by disease extension outside the gland or extracapsular extension outside a lymph node with involvement by metastatic disease. This article reviews the prognosis, diagnosis, management, and implications of invasive thyroid cancer affecting the various structures of the central and lateral compartments of the neck.

The management of thyroid carcinoma invading the larynx or trachea

OBJECTIVES/HYPOTHESIS

To describe the controversies in the management of thyroid carcinoma invading the airway.

STUDY DESIGN

Contemporary review of literature; level of evidence: 5.

RESULTS

Invasion of the larynx or trachea by thyroid carcinoma is uncommon and often identified at the time of operation, when the surgeon must decide the extent of resection. Invasion of the airway is associated with loss of tumor differentiation and a reduction in long-term survival compared to tumors limited to the thyroid gland. Whether or not the invaded airway should be resected remains controversial. Tangential shave excision of tumor is commonly performed, despite a marked risk of local recurrence. Circumferential sleeve resection of the larynx and trachea is safe and lowers the risk of local recurrence. In recurrent disease, laryngotracheal resection provides effective palliation of airway obstruction and hemoptysis.

CONCLUSIONS

Long-term (>10-20 years) prospective studies are required to compare the outcome after shave excision with segmental airway resection for thyroid carcinoma. Based on the current literature and on our experience, we advocate circumferential tracheal resection in the setting of airway involvement.

Surgical management of tracheal shaving for papillary thyroid carcinoma with tracheal invasion

CONCLUSION

Patients showed improved quality of life following tracheal shaving and the carcinoma was well controlled locally, as long as invasion had not progressed to the mucosal surface of the trachea. However, compared with papillary thyroid carcinoma (PTC) with no tracheal invasion, metastasis was common and invasion of organs other than the trachea was frequent, putting many patients into the high-risk group. The clinical course for such patients thus requires careful monitoring, with particular attention to metastasis to other locations. Tracheal shaving can be recommended for patients with PTC with tracheal invasion.

OBJECTIVES

Macroscopically, in cases where invasion into the trachea has not reached the tracheal mucosa surface, we perform tracheal surface resection (tracheal shaving). We retrospectively investigated rates of local control, metastasis and survival in patients who had undergone tracheal shaving.

PATIENTS AND METHODS

Subjects comprised 22 patients with PTC who underwent tracheal shaving between January 1994 and December 2005.

RESULTS

Local control was achieved in 21 patients (95%), and metastasis was seen in 6 patients (27%). With two patients dying from causes other than cancer, 5- and 10-year survival rates were 93% and 41%, respectively. The two surviving patients are still cancer-bearing.

[Cervicovisceral resection in invasive thyroid tumors]

About 6% of patients with thyroid cancer present with life-threatening tumor invasion of the trachea and/or esophagus. The extent of resection depends on tumor diagnosis and stage (indication only in differentiated and perhaps medullary thyroid cancer without extrapulmonary metastases), extent of aerodigestive invasion, and general health state of the patient. After complete tumor resection, 5-year and 10-year survival rates of 40-75% can be achieved. Incomplete tumor resection however has a negative effect on prognosis. Tangential tumor resection (shaving) is indicated if no transmural invasion of trachea/esophagus has occurred. Tracheal resection can be subdivided into six standard procedures--types 1 and 2: laryngotracheal or tracheal window resection; types 3 and 4: circular resection with primary reconstruction infraglottic or tracheal; and types 5 and 6: laryngectomy and cervical evisceration.

Tracheal resection with end-to-end anastomosis preserving paries membranaceus trachea for patients with papillary thyroid carcinoma

CONCLUSION

Sleeve resection of the trachea while preserving the paries membranaceus trachea appears useful for patients in whom papillary thyroid carcinoma has invaded as far as the tracheal mucosa.

OBJECTIVES

While tracheal sleeve resection with end-to-end anastomosis is advantageous, risks of suture failure or other serious complications exist. Since feeding arteries enter the trachea from the posterior and lateral walls, we conduct tracheal anastomosis preserving the paries membranaceus trachea.

PATIENTS AND METHODS

This study retrospectively examined therapeutic outcomes and postoperative complications for sleeve resection followed by end-to-end anastomosis in 12 patients between 1994 and 2005.

RESULTS

Tracheal suture failure occurred in one patient and sutures were redone. One patient developed esophageal fistula, but recovered with conservative treatment. One patient required re-intubation. In three patients, recurrent laryngeal nerves were paralyzed bilaterally. No patients displayed recurrence in the tracheal resection margin or preserved paries membranaceus trachea. The 10-year survival rate was 72.9%.

Management of locally invasive well-differentiated thyroid cancer

Thyroid carcinoma invasion of the aerodigestive tract and recurrent laryngeal nerve (RLN) are important factors with increase in morbidity and mortality. Primary treatment is surgery; the decision about the extent of surgery is difficult, because preserving function is as essential as removal of the tumor. This article discusses the literature relating to the assessment of disease, surgical management, and adjuvant therapy for invasive thyroid cancer of the aerodigestive tract and RLN and makes suggestions based on the authors' experience.

Segmental Laryngotracheal and Tracheal Resection for Invasive Thyroid Carcinoma

BACKGROUND

Laryngotracheal invasion worsens prognosis in patients with thyroid carcinoma. The extent of resection is controversial.

METHODS

We performed a retrospective study of patients with thyroid carcinoma and invasion of the larynx or trachea between 1964 and 2005.

RESULTS

Eighty-two patients, mean age 64 years and 50% female, underwent segmental airway resection. Differentiated carcinoma was present in 76% (62 of 82 patients), prior tracheal "shave" procedures in 40% (33 of 82 patients), transmural invasion in 58% (48 of 82 patients), and preoperative vocal cord paralysis in 35% (29 of 82 patients). There were 29 tracheal and 40 laryngotracheal resections (reconstruction group: 69 patients); 5 underwent laryngectomy, 7 cervical exenteration, and 1 tracheal resection after exenteration (salvage group: 13 patients). Operative mortality was 1.2% (1 of 82 patients) and anastomotic dehiscence 4.3% (3 of 69 patients). Tracheostomy was permanent in 4.3% (3 of 69 patients). Mean follow-up was 6.1 years. After reconstruction, mean survival was 9.4 years and 10-year survival was 40%; after salvage, these were 5.6 years and 15%, respectively. In differentiated carcinoma, thyroidectomy, immediate shave procedure, and delayed (mean, 67 months) resection of airway recurrence in 15 patients resulted in overall and disease-free survival of 13.1 and 5.1 years, respectively, compared with 17.9 and 14.6 years, respectively, after thyroidectomy and early airway resection in 11 patients. Airway symptoms, metastases at presentation, recurrent disease, and salvage operation were associated with decreased survival; airway resection early after thyroidectomy, complete resection, and well-differentiated tumors were associated with improved prognosis.

CONCLUSIONS

Segmental airway resection for invasive thyroid cancer is safe, preserves the voice, and relieves airway obstruction. Complete resection of laryngeal and tracheal invasion during or early after thyroidectomy is associated with improved survival.

Clinical outcome of different modes of resection in papillary thyroid carcinomas with laryngotracheal invasion

AIM

The aim of this study is to evaluate the outcome of different modes of resection in papillary thyroid carcinoma (PTC) with laryngotracheal invasion.

MATERIALS AND METHODS

Sixty-four primary PTCs with laryngotracheal invasion between 1964 and 2003 were retrospectively analyzed (17 men and 47 women; mean age, 61.6 years; mean follow-up, 92.3 months). Thirteen curative resections included six pharyngolaryngoesophagectomies, two total laryngectomies, and five circumferential resections (complete surgery). Eighteen patients who were candidates for curative resection refused to undergo complete surgery to avoid functional impairment, especially laryngeal function (incomplete surgery). Thirty-three patients with minimal invasion underwent shave or partial resection (conservative surgery). Clinical outcomes were compared between the three groups. The influence of different types of surgery and invasion was also evaluated by Cox proportional hazard analysis.

RESULTS

Three (23.1%) complete, 17 (94.4%) incomplete, and 4 (13.8%) conservative surgery patients died of disease (P < 0.0001). The 10-year disease-specific survival (Kaplan-Meier) in complete, incomplete, and conservative surgery patients were 62.9, 11.1, and 87.7%, respectively (log rank test, P < 0.0001). Incomplete surgery related to worse prognosis [p < 0.0001; hazard ratio (HR), 12.9) than complete or conservative surgery. Tracheal deep invasion (p = 0.0019, HR 7.6) and larynx invasion (p < 0.0001, HR 9.9) related to worse prognosis than minimal invasion.

CONCLUSION

Curative resection improves clinical outcomes in PTCs with laryngotracheal invasion. Conservative resection for minimal invasion also can achieve favorable prognosis. The degree of tumor invasion is significantly related to survival.

Design of a New Technique Using a Free Tracheal Autologous Graft for Reconstruction of the Cricoid Cartilage and Trachea

PURPOSE

We devised a new operative procedure to recreate a supporting framework using a free tracheal autologous graft for cricoidal and tracheal defects.

METHODS

We used this new transplantation method to repair the airway defect in five patients who underwent total thyroidectomy with resection of the airway for advanced thyroid cancer. A free graft was taken from the anterior aspect of the trachea and placed over the defect. The surface of the transplanted graft was then surrounded by the adjoining muscle flap. The orifice created by taking the graft was used as a temporary tracheostomy during the early postoperative period.

RESULTS

Fiberscopic examinations and computed tomography scans done over 3-7 years postoperatively showed no airway deformity, subglottic stenosis, graft necrosis, or local recurrence in any of the five patients. The tracheal stoma closed spontaneously within 5 months after the operation in three of the five patients.

CONCLUSION

The advantages of this procedure are: the free tracheal graft has as much strength as a prosthesis to support the respiratory tract; the autologous graft is biologically compatible; and the procedure can be completed in one surgical field and adopted for primary and secondary repair of the tracheal defect.

Aerodigestive Tract Invasion by Well-Differentiated Thyroid Carcinoma: Diagnosis, Management, Prognosis, and Biology

OBJECTIVES/HYPOTHESIS

1) To describe the clinical entity invasive well-differentiated thyroid carcinoma (IWDTC), 2) to determine prognostic factors for survival in patients with IWDTC, 3) to describe and compare types of surgical resection to determine treatment efficacy, 4) to offer a staging system and surgical algorithm for management of patients with IWDTC, 5) to examine alterations in expression of E-cadherin and beta-catenin adhesion molecules in three groups of thyroid tissue and propose a cellular mechanism for invasion of the aerodigestive tract.

STUDY DESIGN

Basic science: quantification of expression of E-cadherin and beta-catenin in three groups of thyroid tissue. Clinical: retrospective review of patients with IWDTC surgically treated and followed over a 45-year time period.

METHODS

Basic science: immunohistochemical staining was used with antibodies against E-cadherin and beta-catenin in three groups of tissue: group 1, normal control thyroid tissue (n = 10); group 2, conventional papillary thyroid carcinoma (n = 20); group 3, IWDTC (n = 12). Intensity scores were given on the basis of protocol. One-way analysis of variance (ANOVA) was used to evaluate differences between groups. Post hoc ANOVA testing was completed. P < .05 was significant. Clinical: patients were divided into three surgical groups within the laryngotracheal subset: group 1, complete resection of gross disease (n = 34); group 2, shave excision (n = 75); group 3, incomplete excision (n = 15). Cox regression analysis was used to determine significance of prognostic factors. Kaplan-Meier plots were used to evaluate survival. P < .05 was significant.

RESULTS

Basic science: a significant difference between the three thyroid tissue groups for E-cadherin expression was demonstrated on one-way ANOVA testing. When controls were compared with either experimental group in post hoc ANOVA testing, differences between all groups were demonstrated (P < .001). For beta-catenin, the intensities of the three groups were not different by one-way ANOVA testing. Similar nonsignificant results were found on post hoc ANOVA testing. Clinical: there was a statistically significant difference in survival for patients with and without involvement of any portion of the endolarynx or trachea (P < .01). There was a significant difference among all three surgical groups when compared (P < .001). When complete and shave groups were compared with gross residual group there was a significant decrease in survival in incomplete resection group (P < .01). Cox regression analysis demonstrated invasion of larynx and trachea were significant prognostic factors for poor outcome. The type of initial resection was significant on multivariate analysis. Removal of all gross disease is a major factor for survival.

CONCLUSIONS

Basic science: there is a decrease in membrane expression of E-cadherin in IWDTC, and loss of this tumor suppressor adhesion molecule may contribute to the invasive nature of well-differentiated thyroid carcinomas. Clinical: laryngotracheal invasion is a significant independent prognostic factor for survival. Patients undergoing shave excision had similar survival when compared with those undergoing radical tumor resection if gross tumor did not remain. Gross intraluminal tumor should be resected completely. Shave excision is adequate for minimal invasion not involving the intraluminal surfaces of the aerodigestive tract.

Aggressive resection of the airway invaded by thyroid carcinoma

BACKGROUND

The aim of this study was to investigate the hypothesis that outcome following concomitant airway resection is superior to that after shaving of the tumour in patients with airway invasion of thyroid carcinoma.

METHODS

The records of 34 patients with thyroid cancer with airway invasion were reviewed retrospectively. In addition to total thyroidectomy, airway resection was performed in 18 patients (group 1), whereas the tumour was shaved away from the airway in the other 16 patients (group 2). 131I was used as postoperative adjuvant therapy in all patients. Metastasis and recurrence of the primary lesion were determined by 131I whole-body scans, serum thyroglobulin levels, and computed tomography or ultrasonography of the neck.

RESULTS

In group 1, two anastomotic dehiscences resulted in one death. Patients in group 2 had a higher rate of local recurrence (relative risk 8.0, P = 0.013) and earlier recurrence (mean(s.e.m.) 2.6(0.8) versus 7.0(1.1) years; P = 0.026) than those in group 1. Median survival was 5.8 and 4.3 years in the 18 patients of group 1 and 16 patients of group 2 (P = 0.259), and the respective 5-year survival rates were 88 and 84 per cent (P = 0.783).

CONCLUSION

Aggressive airway resection can minimize local recurrence of thyroid carcinoma with airway invasion.

Ultrasonography as a Method of Screening for Tracheal Invasion by Papillary Thyroid Cancer

PURPOSE

To assess the reliability of ultrasonography (US) for detecting tracheal invasion by papillary thyroid cancer (PTC).

METHODS

We reviewed the clinical and surgical data of 509 patients who underwent surgery for primary PTC during 2003, after routine preoperative US.

RESULTS

Ultrasonography showed possible tracheal invasion in 43 of the 509 patients. However, the US findings could not be evaluated in 32 patients because of high tumor calcification, a tumor diameter greater than 4 cm, or tumor extension inferior to the clavicle. We shaved the tracheal wall in 11 patients and resected the tracheal wall in 2 patients. The sensitivity of US for diagnosing of tracheal invasion was 91%, the specificity 93%, the predictive value of a positive test 25%, the predictive value of a negative test 99%, and the accuracy 93%.

CONCLUSION

Ultrasonography is a useful method of screening for tracheal invasion. A negative sonogram is a reliable indicator of the absence of tracheal invasion, except when tumors are highly calcified or extend inferior to the clavicle.

Locally advanced differentiated thyroid cancer

Although most patients with differentiated thyroid cancer (DTC) of follicular cell origin enjoy a relatively good prognosis, some patients unfortunately present with or develop locally advanced DTC which leads to significant local morbidity and mortality. DTC accounts for 54-94% of all locally advanced thyroid cancers. DTC invasion of the recurrent laryngeal nerve, strap muscles and trachea are the most common followed by invasion of the esophagus, internal jugular vein and carotid artery. Surgical resection is the primary treatment for locally advanced DTC. Although the optimal surgical approach (ranging from conservative shave excision to aggressive en bloc resection of tumor and vital structures) in patients with locally advanced DTC is controversial, a curative resection should be the goal unless complete tumor resection results in unwanted perioperative morbidity and mortality or widely metastatic disease is present. Postoperative radioiodine ablation with TSH suppression is imperative after surgical resection of locally advanced DTC. Patients with microscopic or small gross residual disease, after surgical resection, may benefit from postoperative external radiotherapy for local control of disease.

Surgical management of thyroid carcinoma invading the trachea

Airway invasion by thyroid carcinoma is an uncommon but important clinical problem. The surgical management of airway invasion is somewhat controversial, with some studies suggesting that conservative shave procedures might be adequate; however, the standardization and safety of techniques of airway resection and reconstruction have made en bloc surgery a reasonable approach for the management of such carcinomas. Tracheal resection and reconstruction for thyroid carcinomas with airway invasion might provide long-lasting palliation and might even be curative in a significant number of patients suffering from this disease.

Using MR imaging to predict invasion of the recurrent laryngeal nerve by thyroid carcinoma

OBJECTIVE

We evaluated the accuracy of MR imaging findings for predicting invasion of the recurrent laryngeal nerve by thyroid carcinoma and established an optimal criterion on which to base this prediction.

MATERIALS AND METHODS

We reviewed MR imaging findings (lesion size and posterior extension of tumor; encirclement of and invasion into the laryngeal cartilage, trachea, and esophagus by the tumor; and the amount of effaced fatty tissue in the tracheoesophageal groove or between the laryngeal cartilage and hypopharyngeal wall) in 66 patients with thyroid carcinoma. The amount of effaced fatty tissue was classified as one of five grades: 1, normal amount of fatty tissue; 2, partly effaced; 3, completely effaced in one MR imaging slice; 4, completely effaced in two contiguous MR slices; and 5, completely effaced in three or more contiguous MR slices.

RESULTS

Thirty-two (48%) of the 66 patients had surgically or pathologically verified recurrent laryngeal nerve invasion. Logistic modeling revealed that the amount of effaced fatty tissue (p < 0.001) and the lesion size (p = 0.033) were the significant factors. Using the threshold values for the lesion size to predict invasion, we found that a threshold of more than 2.9 cm showed the highest accuracy, 76%, with 78% sensitivity and 74% specificity. For the amount of effaced fatty tissue, a grade of 3 or more had the highest accuracy, 88%, with 94% sensitivity and 82% specificity. Addition of the lesion size to this criterion did not improve the diagnostic accuracy of using the amount of effaced fatty tissue alone.

CONCLUSION

Invasion of the recurrent laryngeal nerve by thyroid carcinoma was accurately predicted by the finding of effaced fatty tissue on MR imaging.

Tracheal invasion by thyroid carcinoma: prediction using MR imaging

OBJECTIVE

The purpose of this study was to evaluate the accuracy of MR imaging in predicting tracheal invasion by thyroid carcinomas and to determine MR imaging criteria for diagnosing tracheal invasion.

MATERIALS AND METHODS

MR imaging was performed on the normal trachea of one cadaver and 30 healthy subjects as a standard of reference. Then, MR imaging findings in 67 patients with thyroid carcinoma were reviewed and correlated with surgical and pathologic findings. A logistic regression model was used to determine which MR imaging features were significant for predicting tracheal invasion.

RESULTS

Twenty-three (34%) of the 67 patients had tracheal invasion. Logistic regression model analysis revealed that significant MR characteristics for determining tracheal invasion included soft-tissue signal in the tracheal cartilage (p < 0.001), intraluminal mass (p < 0.001), and degree of tumor circumference around the trachea (p = 0.001). The highest accuracy (90%) for determining tracheal invasion was achieved using a combination of findings. A case was considered positive for tracheal invasion if there was soft-tissue signal in the cartilage, an intraluminal mass, or a tumor that abutted a circumference of the trachea of 180 degrees or greater. Using these factors resulted in seven false-positive diagnoses because soft-tissue signal in the cartilage was sometimes seen in healthy trachea. Although intraluminal mass invariably reflected deep tracheal invasion, soft-tissue signal in the cartilage rarely indicated actual cartilage invasion but rather indicated tumor extension between the cartilaginous rings.

CONCLUSION

Tracheal invasion by thyroid carcinomas can be accurately diagnosed with MR imaging, and using a combination of criteria is the most accurate method of predicting this phenomenon.

Tracheal reconstruction under tension: an experimental study in sheep

AIMS

Invasion of the trachea by thyroid cancer is a difficult problem. Circumferential resection and end-to-end reconstruction is the treatment of choice. The objective of our study was to investigate the effect of tension on tracheal healing and stenosis formation, and to ascertain the maximum tolerable tension.

METHODS

Tracheal resections of 3, 6 and 9 cm with end-to-end anastomosis were performed on 25 sheep. The intraoperative force required for approximation of the tracheal stumps was measured. Luminal stenosis was determined with the aid of computerized planimetry 1, 2, 4, 8 and 24 weeks post-operatively.

RESULTS

A gradual increase of the stenosis rate occurred with increasing tension on the anastomosis. Acceptable results were achieved in the majority of cases without release techniques or tension suture.

CONCLUSIONS

Tracheal anastomosis under tension does not always lead to disruption or separation of the anastomosis. With the additional use of release manoeuvres and tension sutures, tracheal anastomosis under tension are possible without severe stenosis. The additional use of temporary stenting needs to be elucidated.

[Results of tracheal or esophageal resections in invasive thyroid carcinomas]

STUDY AIM

The aim of this retrospective study was to report results of 21 tracheal or esophageal resections for invasive thyroid carcinomas.

PATIENTS AND METHODS

Between January 1988 and August 2000, 21 patients (mean age: 66 years) had a tracheal (n = 10) or esophageal (n = 11) resection for involvement by an invasive thyroid carcinoma. There were eight undifferentiated carcinomas, 11 papillary, one follicular and one epidermoid carcinomas.

RESULTS

One patient died from pulmonary embolism during the postoperative period. Complications were: tracheal fistula (n = 2), tracheal stenosis (n = 1), esophageal fistula (n = 2), recurrent nerve palsies (n = 8) and hypoparathyroidism (n = 4). Seven patients presented local recurrence and seven presented distant metastases. Ten patients were alive and ten patients died of their carcinoma. The mean survival in this study was 26 months (21 months for anaplastic carcinomas and 41 months for differentiated carcinomas).

CONCLUSION

Differentiated thyroid carcinomas have to benefit from a complete tumoral resection; tracheal or esophageal resection is indicated in case of involvement. Anaplastic carcinomas have a poor prognosis; complete resection is indicated only for selected patients; radiotherapy and chemotherapy are used, because surgery is often impossible.

Thyroid carcinoma invading the cervicovisceral axis: routes of invasion and clinical implications

BACKGROUND

Controversy exists about the routes of invasion (extrathyroidal versus lymphogenic extension) when differentiated carcinoma (DTC) and medullary thyroid carcinoma (MTC) invade the cervicovisceral axis (ie, larynx, trachea, esophagus).

METHODS

We carried out an institutional analysis, from November 1994 to October 1999, of 451 consecutive patients undergoing surgery for DTC and MTC.

RESULTS

Irrespective of tumor entity, carcinomas with cervicovisceral invasion (n = 34) were significantly larger and displayed higher pT categories (mainly pT4) than noninvasive carcinomas. In invasive papillary thyroid carcinoma (PTC) and MTC, the rates of positive lymph nodes were significantly higher than in noninvasive controls. When separate logistic regression analyses were fitted for laryngeal, tracheal, and esophageal invasion, extrathyroidal growth (pT4) consistently was a significant factor predictive of invasion in both DTC and MTC, with relative risks of 10.9 to 67.8. As the routes of invasion are similar in DTC and MTC, all data were pooled for multivariate analyses. Herein, the pN1 category had a significant impact only on esophageal invasion, with a relative risk of 4.7.

CONCLUSIONS

Invasion of the cervicovisceral axis is more often caused by extrathyroidal growth than by nodal metastasis. To keep nodal metastasis from encroaching onto the cervicovisceral axis, paratracheal and paraesophageal lymph nodes should be cleared from the cervicocentral compartment at the primary operation.