Distribution of lymph node micrometastasis in pN0 well-differentiated thyroid carcinoma

Central Lymph Node Dissection in Differentiated Thyroid Cancer

BACKGROUND

There has been renewed interest in extensive lymph node dissection for papillary thyroid cancer (PTC), and a number of reports have been published concerning compartment-oriented dissection of regional lymph nodes in PTC. A comprehensive review of this body of literature using evidence-based methodology is pending.

METHODS

Systematic review of the literature using evidence-based criteria.

RESULTS

Issue 1: Systematic compartment-oriented central lymph node dissection (CLND) may decrease recurrence of PTC (Levels IV and V data, no recommendation) and likely improves disease-specific survival (grade C recommendation). Limited level III data suggest survival benefit with the addition of prophylactic dissection to thyroidectomy (grade C recommendation). The addition of CLND to total thyroidectomy can significantly reduce levels of serum thyroglobulin and increase rates of athyroglobulinemia (level IV data, no recommendation). Issue 2: There may be a higher rate of permanent hypoparathyroidism and unintentional permanent nerve injury when CLND is performed with total thyroidectomy than for total thyroidectomy alone (grade C recommendation). Issue 3: Reoperation in the central neck compartment for recurrent PTC may increase the risk of hypoparathyroidism and unintentional nerve injury when compared with total thyroidectomy with or without CLND (grade C recommendation), supporting a more aggressive initial operation.

CONCLUSION

Evidence-based recommendations support CLND for PTC in patients under the care of experienced endocrine surgeons.

Routine ipsilateral level VI lymphadenectomy reduces postoperative thyroglobulin levels in papillary thyroid cancer

BACKGROUND

Lymphadenectomy in clinically node-negative papillary thyroid cancer (PTC) is controversial. The aim of this study is to determine whether routine ipsilateral level VI lymphadenectomy (LNDVI) has advantages over total thyroidectomy (TT) alone.

METHODS

A retrospective cohort study was performed. Patients undergoing surgery for clinically node-negative PTC >1 cm were included. Group A had TT and LNDVI. Group B had TT alone. The number of radioiodine treatments and postablative stimulated serum thyroglobulin (TG) levels were compared.

RESULTS

From 1995 to 2005, 447 patients with clinically node-negative PTC underwent surgery. Group A (n = 56) had TT and LNDVI. Group B (n = 391) had TT alone. Tumor size was equivalent (group A, 20 mm; group B, 23 mm; P = .14) as were MACIS (metastasis, age, completeness of resection, invasion, and size) scores (group A, 4.70; confidence interval, 4.23-5.17; group B, 4.73; confidence interval, 4.4-5.05). Serum postablative TG levels were lower in group A (0.4 microg/L) compared with group B (9.3 microg/L), P = .02. More patients had undetectable TG levels in group A (72%) than in group B (43%) (P < .001). Long-term complications rates were the same.

CONCLUSIONS

In PTC the addition of routine LNDVI results in lower postablation levels of TG and higher rates of athyroglobulinemia when compared with TT alone.

Cyclic strain-mediated matrix metalloproteinase regulation within the vascular endothelium: a force to be reckoned with

The vascular endothelium is a dynamic cellular interface between the vessel wall and the bloodstream, where it regulates the physiological effects of humoral and biomechanical stimuli on vessel tone and remodeling. With respect to the latter hemodynamic stimulus, the endothelium is chronically exposed to mechanical forces in the form of cyclic circumferential strain, resulting from the pulsatile nature of blood flow, and shear stress. Both forces can profoundly modulate endothelial cell (EC) metabolism and function and, under normal physiological conditions, impart an atheroprotective effect that disfavors pathological remodeling of the vessel wall. Moreover, disruption of normal hemodynamic loading can be either causative of or contributory to vascular diseases such as atherosclerosis. EC-matrix interactions are a critical determinant of how the vascular endothelium responds to these forces and unquestionably utilizes matrix metalloproteinases (MMPs), enzymes capable of degrading basement membrane and interstitial matrix molecules, to facilitate force-mediated changes in vascular cell fate. In view of the growing importance of blood flow patterns and mechanotransduction to vascular health and pathophysiology, and considering the potential value of MMPs as therapeutic targets, a timely review of our collective understanding of MMP mechanoregulation and its impact on the vascular endothelium is warranted. More specifically, this review primarily summarizes our current knowledge of how cyclic strain regulates MMP expression and activation within the vascular endothelium and subsequently endeavors to address the direct and indirect consequences of this on vascular EC fate. Possible relevance of these phenomena to vascular endothelial dysfunction and pathological remodeling are also addressed.

Lymphadenectomy for papillary thyroid cancer: Changes in practice over four decades

AIMS

Lymphadenectomy in the management of papillary thyroid cancer (PTC) has evolved. The aim of this study was to examine the changing role of neck dissection as reflected in the practice of a large thyroid unit over four decades.

METHODS

A retrospective cohort study of patients that underwent primary thyroid surgery for papillary cancer in a single unit in the period 1958-2002. Nine 5-year periods were considered and the data relevant to the treatment of the regional lymph nodes reviewed.

RESULTS

Nine hundred patients with PTC underwent surgery between 1958 and 2002 of whom 32.7% underwent lymph node dissection (LND). The use of lymphadenectomy increased from 21.4% in 1958-1962 to 48.1% in 1998-2002 of which 84% underwent a selective lymph node dissection (SLND)-a dissection where the LND is determined by the extent of the disease encountered. The mean number of nodes removed during SLND was 12.6 (range 1-56) of which a mean of 3.1 (24.8%) (0-19) were involved by the disease. Cervical levels 6 and level 4 were those most frequently dissected. There was no statistically significant difference in the complication rates in patients undergoing neck dissection and those not.

CONCLUSION

The four decade experience reflects a move away from modified radical neck dissection and cherry picking towards SLND. Growing evidence suggests that lymphadenopathy in adult PTC is an adverse prognostic factor. SLND, a lymphadenectomy tailored to the extent of the disease process, is the coherent treatment for PTC since it serves the dual purpose of staging as well as control of local disease. This can be achieved with little morbidity when performed in a specialist centre.

Detection and surgical treatment of cervical lymph nodes in differentiated thyroid cancer

There is considerable controversy regarding the treatment of patients with cervical metastases from differentiated thyroid cancer. Most have papillary carcinoma and the main areas of contention relate to methods of assessment and staging, surgical management and mode of follow up. there is little evidence to support elective anatomical imaging with CT or MRI in those patients with suspected or proven malignancy at the primary site as indicated by fine needle aspiration cytology (FNAC) but who have no clinical evidence of nodal disease. The role of routine ultrasound (US) in the pre-operative assessment of suspected or known malignancy is developing but is largely unproven. When it is performed, high risk areas for metastatic neck disease (levels II-V) should be assessed. Suspicious nodes on US should be further evaluated by FNAC. Suspected or proven neck disease may be further assessed pre-operatively with CT or MRI and then treated surgically. Disease in the central compartment requires a total thyroidectomy and level VI central compartment neck dissection. Suspected or proven lateral compartment cancer should be treated by selective neck dissection (at least levels III, IV, and V) below the accessory nerve. There is no role for 'Berry picking' and clinically node negative high risk patients should have an elective central compartment level VI neck dissection. Sentinel node biopsy lays no role and neither does elective lateral compartment surgery in patients with no clinical or radiological evidence of disease. For follow up, US represents the most sensitive means of detecting neck recurrences and in the presence of an elevated serum thyroglobulin, imaging may also include whole body iodine-131 scanning and anatomical imaging with CT or MRI. The role of PET remains controversial but is likely to develop further as the technique becomes more widely available. In the future, the concentration of patients with this disease in large center can only improve the way we treat differentiated thyroid cancer.

[Lymph node dissection in non-medullary differentiated thyroid carcinoma]

Papillary and follicular thyroid carcinomas are the most common form of endocrine carcinomas. Lymph node involvement seems to be a low risk factor for death, but it increases the risk for loco-regional recurrences and distant metastasis. The limits and the key points of the cervical lymph node dissection are described. The sentinel lymph node is used to rarely, so it could limit the lymph dissection. Node-picking has to be avoided. Central lymph node resection is recommended for high-risk patients, as male, patients more than 45 or less than 21 years old, papillary carcinomas greater than 1 cm or follicular carcinoma more than 2 cm in diameter. Lateral lymph node resection is performed when the lymph nodes of the central compartment are involved, more than 3 cm in diameter, and bulked. Prophylactic lymphadenectomy is useless. When thyroid carcinoma is known postoperatively, re-operation depends of the cervical mass and of the results of the radioactive iodine treatment.

The role of a more extensive surgical approach in the initial multimodality management of papillary thyroid cancer in children

PURPOSE

Papillary thyroid cancer (PTC) in children is rare. The optimal initial surgical treatment remains controversial, given the generally favorable overall prognosis but high rate of cervical metastasis and local recurrence. Our objective was to examine the surgical outcomes of a policy of total thyroidectomy and routine selective lymph node dissection (SLND) as the initial surgical approach to children with PTC.

METHODS

This is a retrospective cohort study comprising 14 children (age, < or =17 years) with PTC referred for thyroid surgery during the past 15 years. Clinical presentation, the surgical procedure, final pathology, lymph node involvement, complications, and recurrence rates are reported.

RESULTS

There were 9 females and 5 males, with an average age of 12.5 years. Seven patients (50%) had clinically apparent cervical lymphadenopathy at the time of surgical referral. All subjects underwent total thyroidectomy, and 12 (86%) had SLND. Of the 12 who underwent SLND, 10 (83%) had nodal metastases. Temporary hypocalcemia was noted in 3 of the patients (21%), and 1 patient has required ongoing intermittent calcium supplementation. All patients are alive and well at follow-up with no clinical, biochemical, or radiological evidence of local recurrence.

CONCLUSIONS

Total thyroidectomy with initial SLND is an appropriate surgical approach in children with PTC. It can be done without a significantly increased risk for permanent complications and may reduce the requirement for subsequent surgical intervention for local recurrence in this young population.

Papillary microcarcinoma of the thyroid-Prognostic significance of lymph node metastasis and multifocality

BACKGROUND

It is known that patients with papillary microcarcinoma (PMC) of the thyroid gland have a very favorable prognosis. The rising incidence of PMC among papillary thyroid carcinoma (PTC) necessitates the identification of prognostic factors and the formulation of treatment protocols.

METHODS

The authors conducted a retrospective analysis of 203 patients with PMC who were diagnosed on or before 1999 and were treated at the Department of Clinical Oncology, Queen Elizabeth Hospital, Hong Kong.

RESULTS

The cause specific survival, locoregional (LR) failure free survival, and distant metastases failure free survival rates at 10 years were 100%, 92.1%, and 97.1%, respectively. Five patients had lung metastases; 2 patients died of their metastases 12.9 years and 14.8 years after diagnosis, and 3 patients achieved clinical remission after radioiodine (RAI) treatment. Twelve patients had LR recurrences. Patients with LR recurrence were highly salvageable with a combination of surgery, RAI treatment, and external radiotherapy; all but one (who refused treatment) were alive without disease at last follow-up. Multivariate analyses did not reveal any independent prognostic factor for survival. The risk of cervical lymph node (LN) recurrence increased 6.2-fold (P = 0.01) and 5.6-fold (P = 0.02) when LN metastases and multifocal disease were present at diagnosis. RAI ablation reduced the LN recurrence rate to 0.27 (P = 0.04). The presence of LN metastasis increased the rate of distant metastasis 11.2-fold (P = 0.03). Age was not a significant factor in predicting disease recurrence or survival. Subdivision by tumor sizes </= 5 mm and > 5 mm did not affect the outcome, but no patient with tumors <or= 5 mm had mortality related to PMC.

CONCLUSIONS

Despite the overall excellent prognosis for patients with PMC, PMC was associated with a 1.0% disease-related mortality rate, a 5.0% LN recurrence rate, and a 2.5% distant metastasis rate. Therefore, the treatment of patients with PMC should be no different from the treatment of patients with conventional PTC: i.e., complete surgery with consideration for RAI and/or external radiation therapy if poor prognostic factors are present.

Well-differentiated carcinoma of the thyroid

Thyroid cancer will be diagnosed in more than 20,000 individuals in the United States in 2002. Approximately 16,000 of these patients will be women. During the same year, an estimated 1300 deaths from thyroid cancer are expected. The various types of thyroid cancer include papillary carcinoma, follicular carcinoma, Hurthle cell carcinoma, medullary carcinoma, anaplastic carcinoma, and thyroid lymphoma. Papillary, follicular, and Hurthle cell carcinoma are considered well-differentiated thyroid cancers and constitute the focus of this article.