Anaplastic thyroid cancer
Introduction
Anaplastic thyroid cancer (ATC) remains one of the most deadly diseases. It is responsible for 1.7% of all thyroid cancers in the United States, however geographical prevalence ranges from 1.3% to 9.8%. Overall patients have a median survival of 5 months and less than 20% survive 1 year.[1], [2]
The epithelial cancers of the thyroid include papillary, follicular, hurtle and anaplastic. These are divided into well differentiated thyroid cancers (WDTCs), poorly differentiated thyroid cancer (PDTC) and undifferentiated thyroid cancer (ATC). Internationally the prevalence of ATC has dropped due to improved management of WDTC and dietary iodine. A significant direction has been offered in the management of this disease with the publication of guidelines by the American Thyroid Association (ATA) taskforce on ATC.3 This is a positive step treating these difficult problems.
The American Joint Committee on Cancer (AJCC) has categorized ATC into Stage IVA, B & C. Stages IVA are intrathyroidal tumors, in Stage IVB the primary tumor has evidence of gross extrathyroidal extension and Stage IVC patients have distant metastases. The primary tumors are staged as T4. Since there are no established and effective treatments regimens, reported by any single institution or a group, we have elected to elaborate upon the current guidelines published by the ATA, for management of ATC. Despite the rarity of supportive prospective trials the ATA guidelines frequently make strong recommendations supported by expert opinions. We will consider the key recommendations within this article.
Section snippets
Pathogenesis
The cytological characteristics of this tumor show multinucleated cells with large bizarre nuclei and multiple atypical mitotic figures. There are no features of thyroid differentiation. These tumors have a marked degree of invasiveness, extensive necrosis and are characterized by the presence of spindle, squamoid, giant or osteoclast like giant cells with frequent admixtures of these cell types. The three histopathological patterns of growth (spindle, pleomorphic and squamoid) are not of
Presentation and diagnosis
An efficient and coordinated assessment of the ATC patient is required which demands a multidisciplinary approach. Patients frequently present with progressive airway compromise, and given the early recurrent laryngeal nerve palsy rates, surgeons should complete an airway and vocal cord assessment with fiber optic laryngoscopy. In patients with symptoms suggestive of recurrent laryngeal nerve (RLN), tracheal and or esophageal invasion, panendoscopy and bronchoscopy should be performed
Treatment strategy
A number of studies in the literature have attempted to identify prognostic factors in ATC. Factors which decrease disease-related mortality include age less than 60, tumor size less than 7 cm and less extensive disease on presentation.15 A study of 47 ATC patients’ reports tumor size greater than 5 cm, acute symptoms, leukocytosis and distant metastases were independent risk factors for poor outcome.16 Improved survival indicators include younger age on presentation, greater extent of surgery
Surgery
Recommendation No. 19 guides us through surgical intervention. Initial approach to Stage IVA or IVB disease is tumor resectability. Complete resection is associated with prolonged disease free survival and overall survival with or without adjuvant chemoradiotherapy.[19], [20], [21], [22] Gross resection, and not debulking, is the goal of surgery. This requires consideration of the structures which may be required for an R0/R1 resection and the morbidity and mortality associated with that.
Airway management
Management of the airway in ATC is always a controversial area of debate. Airway intervention is dangerous and many ask, even after successful tracheotomy is it worth the negative quality of life implications. Patients with acute airway symptoms may require tracheotomy, and in those circumstances a cricothroidotomy is advised for rapid airway entry. These cases, in the ATC setting require experienced Head and Neck surgeons and carry a high mortality rate. It may also be of assistance to first
Systemic therapy
Early ATC tumor dissemination and propensity for distant metastases highlights the necessity for effective systemic chemotherapy. There are many avenues of chemotherapeutic interest in the literature currently.
Conclusion
The ATA guidelines on ATC management is an excellent document. The panel should be commended for their clear and concise work.
This disease warrants rapid and effective multidisciplinary care. The patient’s overall clinical status and TNM stage of the tumor should be determined as soon as possible. Excellent communication with the patient and family is essential for education, a realistic expectation of outcome and informed consent prior to the onset of therapy. Patients with Stage IVA/IVB
Conflict of interest statement
None declared.
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