Cervical exenteration and its variants for locally advanced thyroid cancer: when, why, and how?

PURPOSE OF REVIEW

To describe the modern surgical approach for management of advanced thyroid cancers infiltrating the cervicovisceral axis with special attention to well differentiated tumors not amenable to organ-sparing techniques. In particular, cervical exenteration, herein defined as the sum of total thyroidectomy, central compartment and lateral neck dissections, variously associated with total laryngectomy and possible partial or total pharyngoesophagectomy, represents an extreme surgical procedure that, in properly selected cases, allows for reasonable palliation of central compartment life-threatening signs/symptoms if not cure for an advanced oncologic condition.

RECENT FINDINGS

Cervical exenteration is not contraindicated by the presence of limited distant metastases at presentation. Even though it requires that the patient is in general good health as it can be associated with a number of complications and long in-hospital stay, when appropriately planned and performed according to the most recent reconstructive nuances, it allows good oncologic outcomes that are not inferior to those described for similarly advanced primaries of the upper aerodigestive tract. In addition, quality of life and functional results are not significantly different from those described after total laryngectomy for primary laryngeal squamous cell carcinomas.

SUMMARY

Cervical exenteration requires a tertiary, expert, multidisciplinary effort in terms of diagnosis, surgical performance, and postoperative care. A patient-centered decision process is strongly warranted taking into consideration alternative therapeutic and symptom-based palliative strategies.

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.

Analysis of Pattern of Laryngotracheal Invasion by Papillary Thyroid Carcinoma and Their Management: Our Experience

To analyse the pattern of laryngotracheal invasion (LTI) by papillary-thyroid-carcinoma (PTC) and outcomes of their management. We undertook a retrospective chart review to study patterns of LTI by PTC and to evaluate outcomes of surgical modalities used to treat PTC with LTI. Out of 246cases of PTC, 26-cases had LTI (male-12, female-14, mean-age-55.6 years, range 42-73 years). Common clinical presentation were neck swelling, respiratory distress/stridor and vocal cord paralysis in 100%, 8 (30.8%) and 10 (38.5%) cases respectively. PTC was staged according to AJCC-TNM staging system (T4a-24, T4b-02, N1a-12, N1b-14, M0-25, and M1-01). CT-scan showed obvious LTI and tracheal narrowing in 11(42.3%) and 18(69.2%) cases respectively. All cases underwent total thyroidectomy with central-compartment-clearance. Unilateral and bilateral lateral-neck-dissection was performed in 08 and 06cases respectively. Pattern of Intra-operative LTI were as follows: trachea-13cases, trachea and cricoid-05cases, thyroid cartilage-6cases, trachea, cricoid and thyroid cartilage-2 cases and intra-luminal involvement in 4cases. Modified Shin's staging was used to stage LTI. LTI were superficial, deep-extra-luminal and intra-luminal in 13, 09 and 04cases respectively. LTI was managed by shave-excision, window-resection of trachea, sleeve-resection of trachea and anastomosis, partial laryngectomy and total-laryngectomy in 13,02,04,05 and 2 cases respectively. All patients received radio-active-iodine (RAI) and TSH-suppression-therapy post-operatively. Mean follow-up period was two-years (range 18-30 months). One-case had radio-iodine non-avid local recurrence with lung metastases one-year post-operatively. Shave-excision is adequate for tumours not infiltrating into outer perichondrium. Tracheal-resection and total/partial laryngectomy may be required in cases with laryngo-tracheal cartilage or intra-luminal involvement. Adequate surgical excision along with postoperative RAI and TSH-suppression-therapy gives good loco-regional disease control in PTC with LTI.

Tracheal/Laryngeal Infiltration in Thyroid Cancer: a Single-Centre Experience

Around 1/3 of patients of locally advanced carcinoma thyroid present with tracheal infiltration either alone or along with infiltration of other adjacent structures. Even though trachea is infiltrated, adequate resection is the main modality of treatment in these patients. We retrospectively analysed carcinoma thyroid patients who were operated at our institute, between January 2011 and December 2018, and underwent thyroidectomy with tracheal or laryngeal resection. Seventeen patients underwent tracheal/laryngeal resection with thyroidectomy. The mean age of patients was 57 years. Six and eleven were male and female, respectively, 0.14 (82%) patients had dyspnoea on presentation, 6 had hoarseness of voice, 6 had haemoptysis, and in 2 patients, neck swelling was the only complain. Two patients in our study presented with acute stridor, underwent emergency intubation and subsequently surgery. Two other patients had bulky pedunculated tumour in preoperative bronchoscopy and required tracheostomy for intubation before proceeding with surgery. In 11 patients, sleeve resection followed by end-to-end anastomosis was done, window resection was done in 3 patients, partial laryngectomy in 1, and total laryngectomy in 2 patients. In 10 patients (59%), the site of infiltration was in the lateral tracheal wall, with relatively small posterior primary (mean size 3.7 cm) in the thyroid lobe. Two patients developed postoperative complication, one patient with sleeve resection had secondary haemorrhage, and one patient who underwent window resection with myochondrial thyroid lamina flap reconstruction developed salivary fistula. These patients underwent re exploration with tracheostomy and were subsequently decannulated. Preoperative diagnosis of tracheal infiltration helps in better planning of surgery and counseling the patients of any possible complication. Clinical workup and pre-emptive diagnosis is therefore of paramount importance.

Thyroid cancer: surgery for the primary tumor

Surgery is the mainstay of therapy for most patients who present with thyroid cancer. The surgeon must select an appropriate procedure based upon pre operative factors such as tumor histology, extent of primary disease, the presence of regional or distant metastases, associated disease in the contralateral thyroid lobe and the potential for post operative adjuvant therapy. Preservation of the vital structures in the central neck, including the recurrent and superior laryngeal nerves and the parathyroid glands is critical as is the maintenance of absolute hemostasis. In this review article we describe the management of Well Differentiated Thyroid Cancer (WDTC) presenting as a solitary nodule, WDTC in a background of multinodular disease and the management of WDTC presenting as advanced local disease. We go onto discuss the impact that regional and distant metastases have on the choice of surgical approach. The focus of this article is WDTC, however the principles of management of the primary in medullary and anaplastic carcinoma are also discussed.

Invasive thyroid cancer: management of the trachea and esophagus

Well-differentiated thyroid cancer most commonly presents as an intrathyroidal tumor; however, extrathyroidal extension occurs in approximately 6% to 13% of patients and carries a significant negative impact on survival. Extrathyroidal disease may involve critical structures in the central neck, including the recurrent laryngeal nerves, trachea, esophagus, and larynx, requiring surgery extending significantly beyond the thyroid gland. Appropriate surgical management is of great importance and can normalize survival curves, whereas gross residual disease postoperatively may lead to recurrence and decreased survival. Adjuvant postoperative therapies for thyroid cancers with extrathyroidal extension include thyroid hormone suppression, radioactive iodine therapy, and external beam radiotherapy. This summary reviews approaches to the management of invasive thyroid cancers involving the aerodigestive tract.

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.

Locally advanced thyroid cancer

PURPOSE OF REVIEW

The purpose of this review is to summarize existing literature with respect to locally advanced thyroid cancer and define the intricacies of preoperative evaluation, surgical management of involved sites and postoperative treatment.

RECENT FINDINGS

Locally invasive thyroid cancer is an uncommon disease process, which carries significant morbidity and mortality. Current treatment modalities include appropriate surgery, radioactive iodine treatment and external beam radiation therapy. Proper evaluation of the extent of disease, with complete gross tumor removal, is paramount in managing this difficult problem. Surgical treatment is still the mainstay for locally advanced thyroid cancer.

SUMMARY

Little progress has been made in advancing the treatment of locally advanced thyroid cancer. Patient identification, evaluation and proper surgical management with adjuvant therapy, still remain the most effective course of treatment. Aggressive surgical treatment including removal of all gross tumor and still preserving vital structures along with adjuvant therapy is likely to offer the best results. There is a very high incidence of locoregional and distant failure in this group of patients. The understanding and recognition of histopathological variations, such as poorly differentiated thyroid cancer is also important. New molecular markers are needed to help identify and predict aggressive tumor behavior.

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.