The exact cause of thyroid cancer is still not clear, as is the case with most cancers. An assumed theory is thyroid cancer occurs when cells in the thyroid undergo genetic changes (also known as genetic mutations). The mutations allow the cancer cells to grow and multiply at a rapid pace. The cells also lose the ability to die, as normal cells would.
This article shall explore what are the various ways of thyroid cancer treatment and how do such treatments work. It shall also explore the thyroid cancer treatment suitable for different kinds of thyroid cancer.
Thyroid Cancer Diagnosis and Treatment: The Medical Team
In the process of diagnosis to treatment of thyroid cancer, a multidisciplinary medical team including an endocrine pathologist, head and neck surgeon, medical oncologist, radiation oncologist, endocrinologist, and a palliative care physician is essential for optimal management of cancer of the thyroid tissue.
The work of an endocrine pathologist is to provide diagnostic services relating to diseases of endocrine glands including the thyroid, parathyroids, adrenals, and the pituitary. Medical oncologists diagnose thyroid cancer and help in its treatment.
Radiation oncology is a specialized field of cancer study. An endocrinologist specializes in the working of the endocrine system. A palliative care physician is required when the patient has developed a serious illness from cancer.
1. Basic Thyroid Cancer Treatment: The Thyroid Hormone Therapy
The thyroid gland produces hormones needed for the healthy functioning of the cells in our body. Hypothyroidism is a condition in which the thyroid gland does not produce the required amount of hormones.
Blood tests confirm thyroid hormone levels in the body. Increased levels of Thyroid Stimulating Hormone (TSH) means the thyroid is underactive.
Thyroid Hormone therapy or Thyroid Hormone Replacement Therapy is a thyroid cancer treatment technique. The technique aims at compensating for the lack of thyroid hormones namely, T3 or Triiodothyronine and T4 or Thyroxine in the body. Whatever might be the type of thyroid cancer, Thyroid Hormone Replacement Therapy is the base on which all thyroid cancer treatment options are built.
In most thyroid cancers cases, your medical oncologist will prescribe a daily dose of thyroid hormone replacement pills (mostly T4) to be consumed orally.
Like most other cancer treatment options, Thyroid Hormone Therapy can be effective in treating very small thyroid cancers.
1.1. Role Of Hormone Therapy In Thyroid Cancer Treatment
According to the American Thyroid Association, Thyroid Hormone Therapy is administered under these two circumstances generally:
- To replace the function of a thyroid gland that is underactive or has been surgically removed. This is also known as the Replacement Theory, often used to treat various types of thyroid disease.
- To prevent further growth of thyroid tissue, also known as Suppression Therapy. This is primarily used to treat thyroid cancer to prevent recurrence or the spread of cancer cells.
In most patients on thyroxine replacement, the ideal Thyroid Stimulating Hormone (TSH) level is between 0.5 to 2.5 mU/L. Patients who have had thyroid cancers are usually prescribed higher dosages of thyroid hormone pills for the annulation of cancer cells.
Hormone therapy is a common treatment for Follicular thyroid cancer and Papillary thyroid cancers whereas it might not be a suitable treatment option for Medullary Thyroid Cancer.
2. Radioactive Iodine Therapy In Thyroid Cancer Treatment
Radioactive Iodine is a medicine that is taken up by your thyroid gland. Depending on the dosage used, the radioactive iodine destroys most or all of the cancer cells and tissue in your thyroid gland. Radioactive Iodine Treatment or Radioiodine is a common treatment for hyperthyroidism as well as in the treatment of thyroid cancer.
The thyroid cells absorb iodine in your body. Because of this, radioactive iodine can be used to treat thyroid carcinoma. The radioactive iodine collects in the thyroid cells, where the radiation can destroy the thyroid cancer cells and thyroid cells of the thyroid gland that take up iodine, with minimal effect on the rest of your body.
2.1. Radioactive Iodine Treatment: How Does It Work?
The radioactive iodine treatment is usually given after taking out the thyroid gland to destroy any remaining thyroid tissue. Radioactive iodine treatment can be used to ablate (destroy) any thyroid tissue that could not be removed by thyroid surgery or to treat some types of thyroid cancer in which cancer has spread to nearby lymph nodes or other parts of the body.
This might be the case for many types of thyroid cancer like follicular thyroid cancer, papillary thyroid cancer, or, anaplastic thyroid cancer.
According to the National Comprehensive cancer network for cancer patients with Follicular thyroid cancer and Papillary thyroid cancer, the two well-differentiated thyroid cancers Radioactive iodine treatment are the standard thyroid cancer treatment option. Clinical trials are recommended at any stage in thyroid cancer treatment.
To learn more about Radioactive Iodine Therapy, watch this video:
3. Thyroid Cancer Treatment For Medullary Thyroid Cancer
Medullary thyroid cancer is a common type of thyroid cancer in which cancer cells grow in the parafollicular cells which produce calcitonin. Blood tests confirm increased serum concentration of calcitonin. Though Medullary Thyroid Cancer is not curable once it has metastasized (cancer has spread to other parts of the body), it can be cured in its initial stages.
People with multiple endocrine neoplasia types 2A and 2B develop Medullary thyroid cancer. Patients suffering from Medullary thyroid cancer may also develop a thyroid nodule and enlarged lymph nodes.
The several thyroid cancer treatment options available for Medullary Thyroid Cancer are:
3.1. Thyroid Surgery:
Total thyroidectomy with bilateral neck dissection is the most accepted treatment option for medullary thyroid cancer and is almost definitively used when cancer has not spread to lymph nodes in the neck, or to other parts of the body. Risk factors include loss of voice, extensive nerve damage, or even death.
3.2. External Beam Radiation Therapy
External beam radiation therapy is recommended where there’s a chance of reappearance of cancer cells in the thyroid gland i.e., in cases when total thyroidectomy has not helped.
External Beam Radiation Therapy, the most common radiation therapy is a form of targeted therapy in which external ionizing radiation is targeted at the entire thyroid gland or in the thyroid cells where cancer has spread. Radiation Therapy is mostly used to kill cancer cells, although it can kill healthy thyroid cells, without causing harm.
The success rate for External Radiation Therapy in treating Medullary thyroid cancer according to a study by the American Cancer Society is between 50-80%.
3.3. Protein Kinase Inhibitors: Resist Cancer Cells
Protein kinase inhibitors, as the name suggests inhibit the abnormal growth of the protein kinase which is a protein involved in the growth of medullary cancer cells. Clinical trials of protein kinase inhibitors indicate that 10-30% of patients have been responsive to this treatment option which has also helped relieve symptoms of thyroid cancer.
3.4. The Contribution Of Clinical Trials
Antibodies attached to a radioactive substance, known as Radiolabeled antibodies are being tested for MTC (Medullary Thyroid Cancer)
Researchers continue to study the two drugs, named vandetanib and cabozantinib for MTC, including for use of children who have advanced familial MTC.
Here’s a video to guide you through Radiation Therapy for thyroid cancer treatment:
4. Thyroid Cancer Surgery: The Most Effective Thyroid Cancer Treatment
Surgery is both the recommended and desired treatment for most thyroid cancers. Surgery options include:
A lobectomy is an operation in which the lobe containing cancer is taken out usually along with the isthmus. It can be used to treat differentiated (papillary or follicular) thyroid cancers that are small and show no signs of spread. It is also sometimes used to diagnose thyroid cancer in the case when an FNA biopsy result doesn’t provide a clear diagnosis.
One advantage of this surgery is that some patients might not need to take thyroid hormone pills afterward because it doesn’t remove the entire thyroid gland. However, having some thyroid left can interfere with some tests that look for cancer recurrence after treatment.
Unlike lobectomy, Thyroidectomy removes the thyroid gland. It is the most commonly recommended surgery for thyroid cancer. Like lobectomy, thyroidectomy is typically done through a few-inch incision across the front of the neck.
A total thyroidectomy is when the entire thyroid gland is removed. However, this is not always viable to the surgeon in which case a near-total thyroidectomy is performed.
After a near-total or total thyroidectomy, the patient needs to take daily thyroid hormone pills. Unlike lobectomy, thyroidectomy allows checking for recurrence of cancer afterward through radioiodine scans and thyroglobulin blood tests.
4.3. Lymph Node Removal
Lymph node removal is surgery to remove lymph nodes in the neck. This kind of surgery is especially important for the treatment of medullary thyroid cancer and for anaplastic cancer (for when surgery is an option.)
For papillary or follicular cancer types where only 1 or 2 enlarged lymph nodes are diagnosed to contain cancer, such nodes may be removed. Any small deposits of cancer cells that may be left are afterward treated with radioactive iodine.
Central compartment neck dissection is a surgery through which several lymph nodes near the thyroid are removed. A modified radical neck dissection is done to remove lymph nodes on the side of the neck.
5. Thyroid Cancer Treatment: The Case Of Anaplastic Thyroid Cancer
An aggressive type of thyroid cancer, Anaplastic Thyroid Cancer is marked by the abnormal growth of cancer cells in the thyroid gland. Its resistance to genric treatments for thyroid cancer and aggressive growth makes its prognosis fairly difficult. The American Thyroid Association states that this type is so rare that it represents less than 2 percent of all cases of thyroid carcinoma.
The cancer cells metastasize very quickly to other organs, hence is more than often diagnosed as advanced thyroid cancer. This also makes Anaplastic thyroid cancer need critical emergency care, failing which asphyxiation can occur.
5.1. Ways To Manage Anaplastic Thyroid Cancer
Anaplastic thyroid cancer is not a differentiated thyroid cancer, and hence most likely incurable. Radiation therapy combined with chemotherapy and tracheostomy are methods that can be adapted to control this aggressive type of thyroid cancer.
Several ongoing clinical trials demonstrate that immunotherapy might play an important role in anaplastic thyroid cancer management.
5.2. Contribution Of Clinical Trials
Joining a clinical trial allows one to gain access to investigational drugs or treatments that are otherwise unavailable to patients diagnosed with thyroid cancer.
Several clinical trials are being carried out with respect to Anaplastic thyroid cancer. Medications such as fosbreatbulin, bortezomib, and TRAIL , which have emerged as results of the clinical trials can help cope with Anaplastic Thyroid Cancer.
In the case of anaplastic thyroid cancers, clinical trials are studying combination chemotherapy. One such clinical trial study compares the results of either carboplatin (Paraplatin) and paclitaxel (Taxol) alone or with an experimental drug, combretastatin A4 phosphate (CA4P, fosbretabulin, Zybrestat).
For follicular and anaplastic thyroid cancers, valproic acid is being researched as a possible treatment.
6. Thyroid Cancer Treatment For Stage IV Thyroid Cancer
Stage IV thyroid cancer is metastatic thyroid cancer, meaning thyroid cancer cells have metastasized to the lymph nodes, the pituitary gland, the whole endocrine system, and to other parts of the body. Treatment options for this form of thyroid cancer are limited.
The prognosis for Stage IV thyroid cancer depends on a number of things like the type of thyroid cancer, whether cancer has formed a thyroid nodule or thyroid nodules, how far has cancer spread, if the cancer is differentiated thyroid cancer, treatments received, the patient’s age and overall health.
In the arena of new treatments for thyroid cancer, according to the National Cancer Institute, the Food and Drug Administration (FDA) has approved two targeted drugs for Aggressive Papillary Thyroid Cancers: sorafenib tosylate (Nexavar) and lenvatinib (Lenvima). Both drugs block the action of several different altered proteins that promote cancer cell growth.
7. Clinical Trials To Battle Thyroid Cancer
Like for every other disease, Clinical Trials are not uncommon as a thyroid cancer treatment option. The process of the clinical trial includes testing new medications and drugs known as targeted therapy.
Targeted therapy is a treatment that is targeted at specific genes, proteins, or the tissues that contribute to thyroid cancer cells’ survival and growth. In addition, researchers at clinical trials are looking at new treatments of chemotherapy and other combinations of treatments.
7.1. Areas Of Research In Thyroid Cancer Treatment Clinical Trials
i) Clinical trials refer to research studies performed on people. They aim to evaluate an intervention of the medical, surgical, or behavioral kind. Clinical trials are the main way through which researchers find out if a new treatment, like a new drug, diet type, or medical device (for example, a heart stent) will be safe and effective when used on other people.
ii) For advanced-stage differentiated thyroid cancers that do not respond to partial or total thyroidectomy or when the I-131 treatment stops responding, clinical trials are studying several targeted therapies called vascular endothelial growth factor (VEGF) inhibitors.
iii) These inhibitors are likely to block the creation of new blood vessels that are necessary for the growth of thyroid tumors. VEGF inhibitors under clinical trials are axitinib (Inlyta), nintedanib (Ofev, Vargatef), and pazopanib (Votrient).
Also, when a type of thyroid cancer has a genetic mutation known as BRAF V600E, the study drug has helped to kill cancer cells more in such cases. Dabrafenib (Tafinlar) and trametinib (Mekinist) are also being studied for those tumors with the BRAF genetic mutation.
iv) For thyroid cancers that don’t respond well to I-131, new approaches are being tested. One such drug being studied under a clinical trial is called selumetinib. The purpose of testing this drug is to see if it helps boost I-131 absorption in treating advanced types of thyroid cancer. Other drugs under study include a combination of temsirolimus or Torisel and sorafenib or Nexavar.
v) Investigations are underway to fine-tune diagnosis and predict treatment outcomes based on the molecular biology of the tumor. Molecular biology is the study of the structure and function of cells at the molecular level.
vi) Clinal trials continue to investigate the best use of I-131, including different dosages, to treat cancer. In one clinical study, researchers are looking at whether taking a drug called sunitinib (Sutent) after I-131 is helpful to those whose cancer diagnosis had been in an advanced stage.
vii) The genetic testing and the refinement of RET oncogenes (notwithstanding some risk factors) is an ongoing area of active research that has led to advancements to treat cancer. Further knowledge in this area can improve how cancer treatment options are chosen and give a more precise prognosis.
viii) Preliminary studies on 2 targeted therapies called LOXO-292 and BLU-667 suggest they have fewer side effects and better response rates for patients where the Medullary thyroid Cancer has spread to lymph nodes and other body parts.
The following video will help you understand thyroid cancer and its types:
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