Thyroid cancer is a malignant condition affecting the thyroid, a vital gland in the neck responsible for producing hormones that regulate metabolism, growth, and development.
What Are the Symptoms of Thyroid Cancer?
Thyroid lumps form more than one-third of the cases seen in patients with neck lumps. The main presentation of thyroid cancer is with a simple non-symptomatic lump in the lower part of the neck. The lump that moves up with swallowing in the lower part of the neck is in the majority of thyroid origin. This test can be conducted by the patient by feeling the lump and swallowing, if the lump moves up on swallowing, it is likely to be thyroid in origin. In normal circumstances, the thyroid gland should not be easily felt.
Thyroid lumps that are cancerous in general feel hard and may be more fixed to the surrounding tissue because they may have invaded the surrounding structures. Thyroid cancer can also present with other symptoms such as hoarse voice (due to the voice nerve destruction), breathing difficulty (due to underlying windpipe obstruction by the gland or chest mass), swallowing discomfort (due to the size of the mass) or upper neck swellings (due to spread of the tumour to the neck lymph glands).
What Are the Risk Factors of Thyroid Cancer?
Several factors can increase the likelihood of developing thyroid cancer, such as:
- Exposure to Radiation Treatments - Radiation therapy to the head or neck, especially during childhood, increases the risk for thyroid cancer.
- Thyroid Conditions - Conditions like goitre or Hashimoto's thyroiditis can increase the risk of thyroid cancer.
- Gender - Women are more likely to develop thyroid cancer than men.
- Age - While thyroid cancer can occur at any age, people between the ages of 30 and 60 are at greater risk.
- Obesity - A higher body mass index (BMI) has been associated with an increased risk of thyroid cancer.
- Genetic Predisposition - A family history of thyroid disease, particularly nodules or cancers, can elevate an individual's risk.
- Low Iodine Diet - Low iodine intake is linked to a higher incidence of follicular thyroid cancer.
How Is Thyroid Cancer Diagnosed?
Diagnosing thyroid cancer involves a combination of physical examinations, laboratory tests, and imaging procedures. Here is an overview of the primary diagnostic methods used in thyroid cancer screening:
- Physical Exam - Your doctor will check for any lumps, swelling, or abnormalities in the thyroid gland. This assessment helps determine if further testing is necessary.
- Blood Test - While blood tests cannot directly diagnose thyroid cancer, they are essential in evaluating thyroid function.
- Thyroid Ultrasound - Sound waves are used to create detailed images of the thyroid. This helps identify any nodules and determine if they are solid or filled with fluid. It can also check nearby lymph nodes for signs of cancer.
- Thyroid Biopsy - A small needle is used to take small sample of cells for lab analysis. The results will determine if cancer cells are present and what type of thyroid cancer it might be.
What Are the Types of Thyroid Cancer?
There are several forms of thyroid cancer, which are staged in different ways. The commonest form of thyroid cancer is the well-differentiated thyroid cancers known as papillary or follicular thyroid cancer.
Unlike most other cancers, differentiated thyroid cancers (DTC) are not staged before treatment. The staging of DTC is done after thyroid and neck surgeries. The staging is done by a radioactive tracer called Radio-Active-Iodine (RAI). Thyroid cells, including thyroid cancer cells, actively take in Iodine in the bloodstream.
When a patient is fed with RAI, this allows the tracer to seek out thyroid cancer cells anywhere in the body. This is by far the most accurate way of looking for spread of DTC. If the patient has not had a near complete thyroid cancer removal, the RAI will congregate in the normal thyroid tissue and thus the RAI scan will not be helpful. Staging therefore can only take place only after thyroid removal.
The other types of thyroid cancer are Medullary Thyroid Cancer (MTC) and Anaplastic Thyroid cancer (ATC). MTC is actually from parafollicular C cells embedded in thyroid gland and they produce a protein Calcitonin that can be used to measure active disease. The natural course of MTC is usually indolent although it can spread to the liver and lung. RAI and PET scans have not been found to be helpful for detecting spread. Normal CT are the recommended staging tools.
ATC is an unfortunate lethal condition that usually spreads aggressively from the thyroid to the surrounding tissues in months. The average survivor period is between 6-12 months. Staging using a PET scan is sometimes helpful.
What Are the Options for Thyroid Cancer Treatment?
Thyroid cancer treatment varies based on the type, stage, and individual patient factors. A combination of therapies is often employed to manage the disease and improve outcomes effectively. The primary treatment options include:
- Thyroid cancer surgery - Depending on the type and stage of cancer, patients may undergo a total thyroidectomy (removal of the entire thyroid) or a partial thyroidectomy (removal of part of the thyroid). Additionally, lymph nodes in the neck may be removed if cancer has spread to them. This approach aims to eliminate cancerous tissue and reduce the risk of recurrence.
- Hormone Therapy - After surgery, patients often require hormone replacement therapy to compensate for the loss of thyroid function.
- Radioactive Iodine Treatment - Patients may be prescribed radioactive iodine to target and destroy any remaining thyroid cancer cells after surgery. It is particularly effective for differentiated thyroid cancers, such as papillary and follicular types, which absorb iodine.
- External Beam Radiation Therapy - High-energy rays are used to kill cancer cells. This treatment is generally reserved for cases where surgery is not an option or if the cancer has spread beyond the thyroid. It may also be used post-surgery if there are concerns about residual disease.
- Targeted Medicines - Targeted therapies can be used when other treatments are ineffective or if the cancer has metastasised. Tyrosine kinase inhibitors (TKIs) like lenvatinib and sorafenib are examples used for advanced thyroid cancers.
- Chemotherapy - Chemotherapy involves using drugs to kill fast-growing cancer cells but can have significant side effects. It is not often used for thyroid cancer, but may be considered if the disease has advanced significantly or recurred after other treatments.
If you are seeking care for thyroid conditions or want to learn more about the available treatment options, please schedule a consultation with A/Prof Luke Tan today; he is a well-known ear, nose, and throat specialist in Singapore, recognised in thyroid as well as head and neck surgeries.
