What is Anaplastic Thyroid Cancer?
Anaplastic thyroid cancer is a rare and highly aggressive form of thyroid cancer that originates from the follicular cells of the thyroid gland. Unlike other types of thyroid cancer, such as papillary or follicular thyroid cancer, ATC is undifferentiated, meaning the cancer cells do not resemble normal thyroid cells.
Incidence and Prevalence
ATC accounts for less than 2% of all thyroid cancer cases but is responsible for nearly half of thyroid cancer-related deaths due to its rapid growth and resistance to conventional treatments. ATC typically affects older adults, often those over 60. Women are more frequently diagnosed than men.
Risk Factors
The exact cause of ATC is not well understood, but several factors have been identified that may increase the risk of developing this aggressive cancer. Besides age and sex (as discussed in the previous section), risk factors for ATC generally include:
- Pre-existing thyroid conditions: Individuals with a history of thyroid disease, including goiter or differentiated thyroid cancer (such as papillary or follicular thyroid cancer), are at increased risk.
- Genetic mutations: Certain genetic mutations and alterations, such as those he p53 tumor suppressor gene, BRAF, and RAS oncogenes, have been associated with ATC.
- Radiation exposure: Previous exposure to radiation, particularly in the head and neck region, can increase the risk of thyroid cancers, including ATC.
Symptoms of Anaplastic Thyroid Cancer
Due to its aggressive nature, ATC symptoms often appear suddenly and progress rapidly. Symptoms typically include:
- A rapidly growing lump or mass in the neck
- Difficulty swallowing (dysphagia): As the tumor grows, it may press on the esophagus, making swallowing difficult.
- Hoarseness or voice changes: If the tumor affects the vocal cords or surrounding nerves, it can cause hoarseness or changes in the voice.
- Breathing difficulties: The tumor can compress the trachea, leading to shortness of breath (dyspnea) or noisy breathing (stridor).
- Persistent pain in the neck and throat area
- Cough, sometimes with blood (hemoptysis)
Diagnostic Methods
Anaplastic thyroid cancer is often diagnosed at stage IV due to its aggressive nature. Diagnosing anaplastic thyroid cancer involves several steps and tests to confirm its presence and understand its extent. Here are the common diagnostic procedures:
- Physical examination: A thorough examination involving the palpation of the neck for lumps or swelling.
- Imaging tests:
- An ultrasound is used to visualize the thyroid gland and detect abnormalities.
- A CT Scan/MRI helps determine the size and spread of the tumor.
- A PET Scan helps identify cancer spread to other parts of the body.
- Fine-Needle Aspiration (FNA) biopsy: A needle is used to extract cells from the thyroid mass for microscopic examination to confirm the presence of cancer and determine its type.
- Molecular testing: Genetic testing may be performed to identify specific genetic mutations that can influence treatment options.
Treatment Options for Anaplastic Thyroid Cancer
Due to its aggressive behavior, ATC requires a multimodal treatment approach. Treatment options include:
Surgery
Surgery is often the first line of treatment for ATC, aiming to remove the primary tumor and any affected lymph nodes. However, ATC is often diagnosed at a stage where complete surgical removal is not possible.. Surgical intervention may include:
- Total thyroidectomy: Removal of the entire thyroid gland.
- Debulking surgery: Partial removal to reduce tumor burden and alleviate symptoms.
- Lymph node dissection: Removal of affected lymph nodes to prevent further spread.
Radiation Therapy
Radiation therapy uses high-energy beams to destroy cancer cells. It is often employed post-surgery or as a standalone treatment when surgery is not feasible. Techniques include:
- External Beam Radiation Therapy (EBRT) which directs radiation at the tumor from outside the body.
- Intensity-Modulated Radiation Therapy (IMRT), a more precise form of EBRT that minimizes damage to surrounding tissues.
Side effects of radiation therapy include skin irritation, fatigue, and difficulty swallowing.
Chemotherapy
Chemotherapy involves the use of drugs to kill rapidly dividing cancer cells. Commonly used chemotherapeutic agents for ATC include:
- Doxorubicin: An anthracycline antibiotic that interferes with DNA replication.
- Cisplatin: A platinum-based drug that causes DNA damage, leading to cell death.
- Paclitaxel: A mitotic inhibitor that prevents cancer cells from dividing.
Chemotherapy may be used in combination with radiation therapy (chemoradiation). Side effects of chemotherapy include nausea, vomiting, hair loss, and increased risk of infections.
Targeted Therapy
Targeted therapy focuses on specific molecular targets associated with cancer growth and progression. The following are some targeted therapies for ATC include:
- BRAF inhibitors for tumors with BRAF mutations (e.g., dabrafenib).
- MEK inhibitors (e.g., trametinib)
- Tyrosine Kinase Inhibitors (TKIs) that inhibit signaling pathways essential for cancer cell survival (e.g., sorafenib, lenvatinib).
These therapies offer the potential for improved outcomes with fewer side effects compared to conventional chemotherapy.
Prognosis and Survival Rates
Unlike other thyroid cancers, ATC is resistant to most standard treatments, making it particularly deadly. The 5-year survival rate is less than 10%, with many patients surviving only 6 months to a year after diagnosis. Factors influencing prognosis include:
- Stage at diagnosis: Early-stage diagnosis can improve outcomes, though it is rare.
- Age and health: Younger, healthier patients may respond better to aggressive treatment.
- Molecular profile: Certain genetic mutations may influence treatment response and survival.
Supportive and Palliative Care
Because curative treatments for ATC are limited, supportive care and palliative treatment are especially important in the management of the disease. Supportive care is offered throughout the disease course and focuses on managing symptoms and side effects caused by the cancer itself or its treatment, while palliative care can be introduced at any stage in the course of the disease. Both approaches work together to create a holistic treatment plan that addresses the physical, emotional, and social needs of the patient. The goal is to maximize comfort, manage symptoms effectively, and improve quality of life for patients with ATC.
Supportive and palliative care typically include:
- Pain management with medication
- Nutritional support to ensure adequate intake
- Respiratory support if breathing difficulties arise
- Speech therapy if swallowing is affected
- Psychological counseling to address emotional and mental well-being
Social and Emotional Support
Living with anaplastic thyroid cancer can be challenging, both physically and emotionally. Support from healthcare providers, family, and support groups is therefore vital to ATC patients. Organizations like the American Cancer Society and the Thyroid Cancer Survivors’ Association (ThyCa) provide valuable resources and support networks for patients and their families.
ThyForLife Health also offers an anonymous global community supporting all thyroid conditions, including all types of thyroid cancer. Currently, the community is available only in the English language. To join this community, download the ThyForLife app on the Apple App Store or Google PlayStore.
Key takeaways
- Anaplastic thyroid cancer is a rare and aggressive form of thyroid cancer with significant treatment challenges and a poor prognosis.
- The diagnosis of ATC typically involves a combination of physical examinations, imaging studies, and biopsy procedures.
- Early detection, a comprehensive treatment approach, and ongoing research into new therapies are critical to improving outcomes for patients with ATC.
- Newer treatments that target specific genetic mutations in the cancer cells, such as BRAF inhibitors (e.g., dabrafenib) and MEK inhibitors (e.g., trametinib) can be effective in some cases.
- Support from healthcare providers, family, and support networks is essential for managing the physical and emotional impacts of the disease.
- The primary goal of supportive care and palliative treatment in ATC is to enhance the patient’s comfort and quality of life as much as possible.
