Anaplastic Cancer, Lymphoma, and Metastases of the Thyroid Gland

Prevalencia de tumores metastásicos en la glándula tiroides. Revisión sistemática y metanálisis

Introducción y objetivo: Los tumores metastásicos en la glándula tiroides complican el diagnóstico, el tratamiento y el pronóstico del paciente. El objetivo es conocer la prevalencia de las metástasis en la glándula tiroides referida en la literatura médica y los tumores primarios que con más frecuencia metastatizan en la glándula tiroides. Método: Se realizó una revisión bibliográfica sistemática en las bases de datos de PubMed, La Biblioteca Cochrane y Scopus. Los artículos seleccionados se dividieron en dos grupos, series clínicas de pacientes en los que se hallaron metástasis en tiroides (grupo A) y series de hallazgos de metástasis en tiroides en autopsias (grupo B). Se realizó metanálisis de prevalencia para cada grupo de artículos siguiendo el modelo de efectos aleatorios. Resultados: La prevalencia en cada grupo con su índice de confianza al 95% fue 0.00479 (0.002-0.007) para el grupo A y 0.0362 (0.014-0.059) para el grupo B. La prevalencia de metástasis halladas en autopsias fue 7,58 veces mayor que en los estudios clínicos. En el grupo A la edad media fue 60.82 y en el grupo B 57.20. En ambos grupos las metástasis halladas en tiroides fueron más frecuentes en el sexo femenino. La localización del tumor primario fue diferente en ambos grupos, en el grupo A fue el cáncer de riñón y en el grupo B el cáncer de mama. La variabilidad de la prevalencia de metástasis en tiroides en los diferentes artículos de ambos grupos hace que este estudio tuviese una alta heterogeneidad (índice I2 y Q). Los funnel plot de ambos grupos indicaron alto sesgo de publicación. Discusión: La diferente prevalencia entre series clínicas y autopsias puede implicar que la detección de metástasis en tiroides en la clínica está infradiagnosticada. La razón de esto podría ser que las metástasis intratiroideas se presentan de forma asintomática siendo diagnosticadas como hallazgo casual en autopsias. En otras ocasiones se presentan como un nódulo tiroideo años después del tumor primario, lo que condiciona el diagnóstico. Conclusiones: La prevalencia de metástasis en tiroides es superior en las series de autopsias que en series clínicas (hasta 6.67 veces más frecuente en nuestro estudio). Las metástasis intratiroideas probablemente están infradiagnosticadas por cursar sin clínica siendo diagnosticadas como hallazgo casual en autopsias. Los tumores primarios más frecuentes fueron el riñón (series clínicas) y la mama (series de autopsias).

Poorly Differentiated and Anaplastic Thyroid Cancer

BACKGROUND

Poorly differentiated thyroid carcinoma (PDTC) and anaplastic (undifferentiated) thyroid carcinoma (ATC) comprise a small subset of thyroid tumors that are associated with a poor prognosis and account for a significant portion of the morbidity and mortality related to thyroid cancer. Since management strategies vary between these two entities, it is important for clinicians to be able to differentiate PDTC from ATC.

METHODS

We reviewed the literature on PDTC and ATC and compared clinical and histopathologic features important in defining the disease process.

RESULTS

Both PDTC and ATC display aggressive behavior with increased locoregional and distant disease. In most cases, patients are older and have large, locally advanced tumors. PDTC may represent an intermediate entity in the progression of well-differentiated thyroid carcinoma to ATC. The use of surgical management may be curative or palliative and differs between PDTC and ATC. The roles of radiotherapy and chemotherapy have not been well described.

CONCLUSIONS

PDTC and ATC are rare diseases that carry a poor prognosis. Recognition of their different clinicopathologic features is important to the optimal management of these tumors.

Description and Comparison of the Sonographic Characteristics of Poorly Differentiated Thyroid Carcinoma and Anaplastic Thyroid Carcinoma

OBJECTIVES

Although poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma account for a substantial portion of the morbidity and mortality associated with thyroid cancer, a chance of a cure exists with aggressive treatment, especially in patients with poorly differentiated thyroid carcinoma. The goal of this study was to evaluate the sonographic characteristics of poorly differentiated thyroid carcinoma and to compare the sonographic findings of poorly differentiated and anaplastic thyroid carcinomas.

METHODS

The study included 29 patients with 30 poorly differentiated thyroid carcinomas and 26 patients with 26 anaplastic thyroid carcinomas. Two radiologists retrospectively reviewed sonographic findings. Clinical and sonographic findings were compared between poorly differentiated and anaplastic thyroid carcinomas by univariate and multivariate analyses.

RESULTS

In the group of patients with poorly differentiated thyroid carcinoma, the mean age was 53.7 years (range, 14-73 years), and the mean tumor size was 3.6 cm (range, 0.6-10.0 cm). The common sonographic findings of poorly differentiated thyroid carcinoma were heterogeneous echogenicity (93.3%), solitary nodules (80.0%), a circumscribed margin (63.3%), an oval-to-round shape (63.3%), and hypoechogenicity (60.0%). A circumscribed margin (P = .003) and an oval-to-round shape (P = .015) were significantly more frequent in poorly differentiated thyroid carcinoma than in anaplastic thyroid carcinoma. In the multivariate analysis, only the circumscribed margin on sonography was an independent predicting factor for poorly differentiated thyroid carcinoma (odds ratio, 4.642).

CONCLUSIONS

Both poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma commonly present as a relatively large malignant mass on sonography; however, poorly differentiated thyroid carcinoma showed a significantly higher incidence of a circumscribed margin and an oval-to-round shape than anaplastic thyroid carcinoma. Knowledge of sonographic characteristics will be useful for differentiation of poorly differentiated and anaplastic thyroid carcinomas.

Whole-body (18)F-FDG PET/CT in primary non-Hodgkin's lymphoma of the thyroid associated with Hashimoto's thyroiditis and bilateral kidney infiltration

An 82-year-old female patient with hypothyroidism and Hashimoto's thyroiditis noted three years ago to have a small asymmetric goiter (left > right). Nevertheless, a rapid growth of the thyroid over 3-6 months caused dysphagia and shortness of breath. Ultrasound and a thyroid gammagram showed an image consistent with multinodular goiter with a hyperfunctioning nodule in the right lobe. Due to the history of Hashimoto's thyroiditis and a rapid increase in size of the thyroid gland, diagnoses of thyroid lymphoma and anaplastic thyroid cancer were considered. Thyroidectomy was attempted at an outside facility to relieve compressive symptoms. Fine needle aspiration was insufficient for diagnosis, and the product of thyroidectomy confirmed the diagnosis of diffuse large B-cell lymphoma. A positron emission tomography/computed tomography scan was performed in our institution for staging, revealing nodal and extranodal metastasis. Chemotherapy using cyclophosphamide, vincristine and dexamethasone (COP modified) led to a dramatic response of the tumor and a complete resolution of compressive symptoms.

Redifferentiation therapy for thyroid cancer

Thyroid tumorigenesis and carcinogenesis accompany progressive loss of thyroid-specific differentiated functions. Some thyroid cancers are or become dedifferentiated, and they become refractory to efficacy-proven conventional therapies such as radioiodine ablation therapy and thyrotropin (TSH)-suppressive therapy. Redifferentiation therapy by either redifferentiating agents or gene transfer of differentiation-related genes may retard tumor growth and make tumors respond to conventional therapies.

Clinical presentation and treatment of non-Hodgkin's lymphoma of the thyroid gland

BACKGROUND

Non-Hodgkin's lymphoma (NHL) of the thyroid is a rare malignancy. The traditional approach to curative treatment of localized (stages I and II) NHL of the thyroid gland is surgical resection. The recent success of multimodality chemoradiotherapy suggests that surgery should be reserved for providing a tissue diagnosis or relief from acute airway obstruction. It is questionable whether this has made an impact on treatment approaches.

METHODS

Retrospective chart review was conducted for all cases of localized NHL of the thyroid gland treated at Roswell Park Cancer Institute between January 1970 and January 1999.

RESULTS

Ten patients (8 women, 2 men) with a mean age of 56.8 years were identified. Nine patients (90%) presented with a neck mass; seven patients (70%) had a history of Hashimoto's disease. Nine patients (90%) had extensive investigations to rule out extrathyroidal disease. All patients were treated with either a total thyroidectomy (eight patients) or a thyroid lobectomy (two patients). Nine (90%) were initially treated outside of Roswell Park Cancer Institute and referred secondarily for consideration of further therapy. Adjuvant therapy consisting of cyclophosphamide-based chemoradiotherapy was administered to nine patients. Overall survival was 80% at a mean follow-up of 8.6 years with a disease-specific survival rate of 100%.

CONCLUSIONS

A review of the literature suggests that fine needle aspiration (FNA) with flow cytometry and immunohistochemistry can be used to accurately diagnose NHL of the thyroid gland. Open biopsy should be reserved for cases where this technique is not available or where the diagnosis can not be confirmed by FNA alone. Extrathyroidal NHL should be ruled out by chest x-ray, CT scan of the abdomen, and bone marrow biopsy. Further review suggests that the most efficacious therapy is systemic chemotherapy in combination with radiation for local control. Debulking surgery should be used only to provide relief from acute airway obstruction.

Survival and therapeutic modalities in patients with bone metastases of differentiated thyroid carcinomas

Data for patients with bone metastases (BMs) of differentiated thyroid carcinoma (DTC) were retrospectively studied to identify factors associated with survival. We especially studied the impact of therapies. Among the 1977 patients followed for DTC in our department from 1958 to 1999, 109 (77 females and 32 males; age range, 20--87 yr) presented BMS: All patients except 1 underwent total thyroidectomy, followed by radioiodine therapy (> or =3.7 gigabecquerels) in 95 cases. Survival rates at 5 and 10 yr were 41% and 15%, respectively. Univariate analyses indicated that a young age at BM discovery (P < 0.005) and the discovery of BM as a revealing symptom of DTC (P < 0.05) were features significantly associated with improved survival as well as radioiodine therapy (P < 10(-4)) and BM complete surgery (P < 0.02). Using multivariate analysis, the detection of BMs as a revealing symptom of thyroid carcinoma (P < 0.0005), the absence of metastasis appearance in other organs than bones during the follow-up (P < 0.03), the cumulative dose of radioiodine therapy (P < 0.0001), and complete BM surgery in young patients (P < 0.04) appeared as independent prognostic features associated with an improved survival.

High frequency of incidental diagnosis of extrathyroidal neoplastic diseases at the fine-needle aspiration biopsy of laterocervical lymph nodes in patients with thyroid nodules

This study was undertaken to evaluate the frequency of the incidental diagnosis of extrathyroidal lymph node diseases at ultrasound-guided fine-needle aspiration biopsy/cytology (FNAB/C) being done to check the presence of metastatic thyroid cancer in 30 subjects with thyroid nodule (TN) and enlarged cervical lymph nodes (CLN). The patients in whom cytology suggested the presence of malignancy in the TN or in the CLN underwent surgical removal for histologic diagnosis. The spectrum of diseases revealed by this survey included: (1) 10 benign diseases including 1 case of Piringer-Kuchinka lymphadenitis with benign TN; (2) 10 metastatic thyroid cancers (2 anaplastic and 8 papillary cancers); (3) 3 benign TN associated with metastatic invasion of cervical lymph nodes from lung (2 cases) and breast (1 case) cancer; (4) 1 Hodgkin's lymphoma of the cervical lymph nodes with hyperplastic TN; (5) 3 nodal lymphomas with benign thyroid nodule and 2 cases of thyroid lymphoma with nodal invasion; and (6) 1 nodal sarcoidosis with benign TN. The results of this study demonstrate that important neoplastic and hematologic diseases affecting the cervical lymph nodes may frequently be incidentally detected using ultrasonography (US) and FNAB/C in the diagnostic procedure for thyroid nodule.

Dose optimization for the treatment of anaplastic thyroid carcinoma: a comparison of treatment planning techniques

PURPOSE

To evaluate and compare dose optimization for the treatment of anaplastic thyroid carcinoma using a 3D conformal plan, and two 3D intensity-modulated inverse plans.

METHODS AND MATERIALS

After patient immobilization using an alpha cradle and head-mask system, a postoperative CT scan was obtained to delineate the gross tumor volume (GTV), the clinical tumor volume (CTV), and adjacent critical structures. Treatment plans were generated using UM-Plan (University of Michigan), PeacockPlan and Corvus (NOMOS Corporation, Sewickley, PA). Isodoses were displayed in the sagittal, coronal, and multiple axial planes, and dose-volume histograms (DVH) were generated for the GTV, CTV, and critical normal tissues. Treatment times were estimated to compare the practicality of delivering each plan in a busy radiotherapy department.

RESULTS

All three treatment planning systems were able to deliver a minimum dose of 60 Gy to the GTV while keeping the maximum spinal cord dose at or below 45 Gy. However, there were differences in the doses delivered to 50% and 5% of the cord, the minimum CTV dose, and the overall treatment time. The PeacockPlan best spared the uninvolved tissues of the posterior neck, and provided the lowest dose to the cord without compromising the CTV.

CONCLUSIONS

Inverse treatment planning provides superior dose optimization for the treatment of anaplastic thyroid carcinoma. The radiobiologic impact of intensity modulation for this tumor should be further tested clinically.