A rare form of thyroid cancer making up less than 1% of such cancers and usually presents as a rapidly growing neck mass.
Anaplastic thyroid cancer represents only 1% of all thyroid cancers, but contributes 19.9% of the annual thyroid cancer, related mortality, and a median survival of 6.5 months.
Extremely aggressive neoplasm with patient death occurring a few months after diagnosis.
Anaplastic thyroid cancers are aggressive undifferentiated tumors with the disease specific mortality approaching 100%.
Accounts for more than half of the 1200 deaths annually attributed to thyroid cancer in the U.S.
Patients with anaplastic carcinoma are older than those with differentiated thyroid cancers, with the mean age at diagnosis of approximately 71 years.
ATC is the least common type of thyroid cancer, and approximately 50% of patients have a prior or coexistent differentiated carcinoma.
ATC develops from more differentiated tumors due to one or more dedifferentiating steps, particularly the loss of p53 tumor suppressor protein.
Fewer than 10% of patients are younger than 50 years, and 60 to 70% of patients are women.
Its incidence is decreasing because of better management of differentiated thyroid cancers, and because of increased iodine in the diet.
ATCs do not typically concentrate iodine, express TSH receptor, or produce thyroglobulin iodine 131 imaging and therapy cannot be used.
Patients often develop hoarseness, dysphagia, and dyspnea.
Patients may present with an enlarging neck mass, neck pain, Horner’s syndrome, stroke, and hoarseness due to vocal cord paralysis.
Patients present with extensive local invasion, and distant metastases are found at initial disease presentation in 15 to 50% of patients.
The lungs and the pleura are the most common sites of metastases (90%).
About 5 to 15% of patient have bone metastasis, 5% of brain metastasis, and a few have metastasis to the skin, liver, kidneys, pancreas, heart, and adrenal glands.
As a rapidly growing neck mass, it can cause asphyxiation, meaning that local control of the neck disease is crucial.
Most patients have a large, firm palpable mass in the thyroid with or without cervical lymphadenopathy.
Metastatic assessment office reveals locoregional disease and distant metastases.
The most common site of distant metastases is the lungs, followed by bones and brain.
Can often arise from and can coexist with differentiated thyroid cancer, but can also occur de novo.
Diagnosis should be suspected in patients with a history of long-standing differentiated thyroid cancer that have symptoms and findings as noted above.
Mean survival ranging from 4 to 12 months and a 5-year survival rate ranging from 1% to 7.1%.
The diagnosis portends such a poor outcome it is classified as Stage IV regardless of tumor, node or metastatic status, 2% of all thyroid cancers.
Approximately half of affected individuals have distant metastases present at the time of diagnosis.
Most common cause of death is suffocation caused by tumor obstructing the thoracic outlet.
Few patients survive longer than 1 year.
Development of anaplastic thyroid cancer is considered part of the natural course of untreated differentiated thyroid cancer.
Approximately 2% of differentiated thyroid cancer are believed to develop into anaplastic tumors.
ATCs are rarely amenable to complete resection.
Multi modality treatment with surgery, chemotherapy and radio therapy is often needed despite distant metastases at presentation.
In resectable cases, surgery followed by postoperative radiotherapy a chemotherapy can have better outcomes than non-surgical treatment.
All patients with unresectable stage disease should be tested for BRAF mutation status for treatment to BRAF/MEK inhibitors.
40% of ATC‘s harbor a BRAF V600 E pathogenic variant.
Core or surgical biopsies preferred for the diagnosis of ATC.
Diagnostic procedures include direct exam of the larynx and evaluation of vocal cord mobility, and imaging studies, including neck ultrasound, CT scans, and PETCT or MRI scans for accurate staging.
Clinically apparent anaplastic tumors are often unresectable.
There are an increasing number of therapeutic targets including BRAF, NTRK, ALK, RET, MSI, dMMR, and TMB.
ATC’s respond poorly to conventional therapies, RAI is not effective and palliative and supportive care is paramount.