Thyroid cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs is a rare type of cancer that develops in the thyroid, a butterfly-shaped gland located in the neck below the larynx (voice box). The thyroid is responsible for producing the hormones thyroxine (T4) and triiodothyronine (T3), which control important bodily functions such as heart rate, digestion, and body temperature. Thyroid cancers usually develop as an adenomaa benign tumour that develops from the epithelial lining of glands in the body or a carcinomacancer arising from tissues that line organs.
Neuroendocrine cancers are a complex group of tumours that develop in the neuroendocrine system, which is responsible for regulating important bodily functions such as heart rate, bloodthe red bodily fluid that transports oxygen and other nutrients around the body pressure and metabolism. They most commonly develop in the gastro-intestinal tract, pancreasa long, flat organ that sits between the stomach and the spine that plays a key role in digestion and blood sugar regulation, and the lungs; however, they can develop anywhere in the body. These tumours develop from neuroendocrine cellsthe basic structural and functional unit of all living things, which are responsible for receiving signals from the nervous system and producing hormones and peptides (small proteins) in response.
Thyroid cancer has a higher incidence in women, and is most commonly diagnosed in young adults and teenagers. However, anyone can develop this disease.
Types of thyroid cancer
There are four main types of thyroid cancer, that are categorised by the types of cells they develop from.
Papillary thyroid cancer
Papillary thyroid cancer is the most common type of thyroid cancer and is often slow growing. It develops from follicular cells in the thyroid gland, which are responsible for the production and storage of T3 and T4 hormones. Follicular cells also produce thyroglobulin (Tg), which is a protein that assists in the synthesis of T3 and T4. Generally, this type of cancer is easily managed, has a lower metastasiswhen the cancer has spread to other parts of the body, also known as mets rate and has a better prognosisto predict how a disease/condition may progress and what the outcome might be compared to other types of thyroid cancer.
Follicular thyroid cancer
Follicular thyroid cancer is a rare type of thyroid cancer that also develops from follicular cells. Advancedat a late stage, far along follicular thyroid cancer may develop into a more rare and aggressive type of thyroid cancer called Hürthle cell carcinoma. It is the second most common type of thyroid cancer; however, it may appear more aggressive and may have a higher metastasis rate than papillary thyroid cancer.
Medullary thyroid cancer
Medullary thyroid cancer is a rare type of thyroid cancer that develops from parafollicular cells. These cells are responsible for the production of calcitonin, which is a hormonea chemical substance produced by glands in the endocrine system that regulates various functions in the body that controls the levels of calcium and potassium in the body. Medullary thyroid cancer is the third most common type of thyroid cancer, and usually occurs without a family history. Unfortunately, the outcomes of this type may not be as favourable as the more common types of thyroid cancer, may have higher metastasis rates, and the prognosis may not be as good.
Anaplastic thyroid cancer
Anaplastica term used to describe abnormal cancer cells that grow uncontrollably in the body and have little or no resemblence to regular cells thyroid cancer is the rarest form of thyroid cancer. It is known to be highly aggressive and fast growing. It develops from follicular cells, and may develop from papillary or follicular thyroid cancers. Unfortunately, anaplastic thyroid cancer is the most lethal and may not have as good of a prognosis as the more common forms of thyroid cancer.
Treatment
If thyroid cancer is detected, it will be staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumoura tissue mass that forms from groups of unhealthy cells) indicates the size and depth of the tumour.
- N (nodea small lump or mass of tissue in your body) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissuea group of cells that work together to perform a function.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localisedaffecting only one area of body cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for thyroid cancers may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, potentially including:
- Tumour resectionsurgical removal of tissue or part/all of an organ.
- Thyroidectomycomplete or partial removal of the thyroid gland.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Immunotherapya treatment that uses a person's immune system to fight cancer.
- Targeted therapymedication that targets specific molecular features of cancer cells.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Risk factors
The riskthe possibility that something bad will happen factors for thyroid cancer include:
- Previous exposure to radiation.
- Family history of thyroid cancers.
- Mutation of the RET (rearranged during transfection) proto-oncogenea type of gene that normally regulates cell growth and division, but when mutated can cause uncontrollable cell growth and may lead to cancer.
- Having other thyroid conditions, such as thyroid nodules, enlarged thyroid (goitre) or thyroid inflammation (thyroiditis).
- Having multiple endocrine neoplasia type 2 (MEN 2).
- Obesity.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Symptoms
People with thyroid cancer may not present with any symptoms in the early stages of the disease. As the tumour progresses, some of the following symptoms may appear:
- A painless lump in the neck.
- Difficulty swallowing.
- Dyspneadifficulty breathing, shortness of breath.
- Changes in the voice, such as hoarseness.
- Lymphadenopathyswollen lymph nodes/glands, also known as adenopathy in the neck.
Having an overactive or underactive thyroid is not usually a sign of thyroid cancer.
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have thyroid cancer, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Imagingtests that create detailed images of areas inside the body tests, potentially including:
- Ultrasounda type of medical imaging that uses soundwaves to create detailed images of the body .
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- PET (positron emission tomography) scana type of medical imaging that uses radioactive tracers to create detailed images of the body.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
