The Management of Thyroid Carcinoma Metastatic to the Neck and Mediastinum

Routine level VI lymph node dissection for papillary thyroid cancer: surgical technique

Total thyroidectomy is the treatment of choice for clinically significant papillary thyroid cancer (PTC); however, 10-15% develop palpable local recurrence in the cervical lymph nodes. Metastases in the cervical lymph nodes account for 75% of loco-regional recurrence and up to 50% of these patients eventually die of their disease. It is generally accepted that surgical excision of grossly involved lymph node disease should be carried out. The role of routine lymph node dissection, however, is greeted with far more controversy. Regional lymph node metastases have been shown to be associated with more frequent tumour recurrence. Not only is recurrence associated with increased disease-related mortality, but recent data have shown that the presence of involved lymph nodes is associated with adverse survival. Additionally, there have been significant changes to the way patients are managed after treatment for PTC in recent years. Surveillance previously relied on clinical assessment and radioiodine scans whereas now the use of serum thyroglobulin and high-resolution ultrasound are the standard as evidenced by recommendations by the American Thyroid Association. These techniques have greater sensitivity and subsequently lymph node metastases are being detected earlier and more frequently. This has led to a paradigm shift in the aims of treatment of PTC, from a focus on survival data to a focus on disease-free status. Routine central neck lymph node dissection can be carried out with no increased morbidity and can achieve lower 6-month stimulated thyroglobulin levels when compared with total thyroidectomy alone. Routine ipsilateral level VI lymph node dissection in addition to total thyroidectomy should be carried out for the management of clinically significant PTC.

Transcervical superior mediastinal lymphadenectomy in the management of papillary thyroid carcinoma

AIM

Surgery is the treatment of choice for lymph node metastases in papillary thyroid carcinoma. When adequately treated by surgical extirpation, the presence of lymph node involvement does not seem to have a negative impact on cure rates or survival. Surgical lymphadenectomy for metastatic papillary thyroid carcinoma has been well described for both the central and the lateral compartments of the neck. Superior mediastinal lymphadenectomy, however, has only sporadically been mentioned. We describe our experience with transcervical superior mediastinal lymphadenectomy (TSML) that avoids the morbidity of the traditional sternal split.

MATERIALS AND METHODS

This retrospective analysis included 30 patients (24 women and 6 men; age range, 17-72 years) who underwent TSML by the senior author (JLF) for papillary carcinoma metastatic to the superior mediastinum between 1985 and 1999. Histopathologic examination confirmed positive nodes in all the mediastinal dissections. All patients received postoperative I(131).

RESULTS

All the patients are alive after a median follow-up of 5 years (range, 1-14 years). Twenty-nine of 30 patients remain free of disease, whereas one patient is alive with lung and bone metastases. No patient has had local or regional relapse. The only significant complication was a high incidence of temporary (70%) and later permanent (50%) hypoparathyroidism.

CONCLUSIONS

TSML is a safe and effective treatment for superior mediastinal metastases in papillary thyroid carcinoma.

Metastatic thyroid carcinoma: an unusual presentation

A case is described in which the presentation of symmetrical thyroid lesions combined with their unusual site and histological appearance served initially to mask the underlying thyroid neoplasm.

Differentiated thyroid cancer: a stage adapted approach to the treatment of regional lymph node metastases

The controversy in the management of regional lymph nodes in patients with differentiated thyroid cancer is discussed on the basis of a review of the literature. Since no prospective studies have yet compared limited dissections ('node picking') with more extensive dissections [(modified) radical neck dissection], a retrospective analysis was performed using two patient groups in which patients were managed differently with regard to the preoperative diagnosis and treatment of regional lymph node metastases. Only patients with proven lymph node metastases were included in the study. Because of selection methods necessary to create comparable patient groups, only 83 patients could be included in the analysis. There was no difference in survival or recurrence rate in either group, although recurrences occurred less frequently in the explored side of the neck after MRND (3.9% vs. 6.3%). More postoperative morbidity was found in the patients who had been subjected to a more extensive search for and treatment of lymph node metastases. Because of the relatively small number of patients only the difference in occurrence of accessory nerve palsies reached statistical significance (P = 0.05). It is advocated that only in the case of papillary carcinoma with limited lymph node involvement node picking is the procedure of choice. In all other cases a modified radical neck dissection should be standard treatment.

Delayed aerodigestive tract complications following combined therapy for thyroid cancer

Radical surgery for papillary adenocarcinoma of the thyroid has been associated with a significant incidence of complications. In some instances, postoperative irradiation is given when there is some suspicion of persistent or occult disease, although thyroid suppression and ablative radioiodine therapy have proved to be very effective adjuvants to surgery. Three patients with papillary adenocarcinoma of the thyroid developed severe, delayed complications 25, 7, and 2 years, respectively, after treatment with primary radical surgery and postoperative irradiation. The degree of injury to the aerodigestive tract as a result of the surgery and irradiation therapy makes treatment difficult regardless of the modality. The possible mechanisms that cause these complications, along with proposed methods of treatment, are discussed.

Mediastinoscopy for extrathoracic malignancies

Metastatic tumors from extrathoracic sources appear in the mediastinum infrequently and from a variety of locations. In this series of approximately 350 malignancies of the mediastinum, 20 (6%) originated from the breast, prostate, kidney, pelvis, and gastrointestinal tract. A radiologic review of these cases does not identify a unique pattern, although paratracheal masses present most often, while unilateral hilar adenopathy occurs somewhat less frequently. The history of previous surgery for malignancy suggests metastatic disease into the mediastinum. However, other entities of second primaries, lymphoma, Hodgkin's disease, and benign processes warrant consideration. Mediastinoscopy is reemphasized as a valuable diagnostic technique for the solution of these problems.