Thyroid Cancer
Thyroid cancer is the eighth most common cancer in the USA and its incidence is rising (Glikson, Alon, Bedrin & Talmi, 2017). It is the most common hormone-related malignancy, representing 1.5% of all newly diagnosed cancers throughout the world. The increasing incidence is partly due to more frequent use of imaging techniques for all thyroid conditions, but over 60-70% of cancers arise from as from genetic, dietary, lifestyle and environmental influences (Moore, Panjwani, Gray, Finnerty, Zarnegar & Fahey, 2017; ).
The thyroid gland makes thyroid hormones which affect all cells in the body. Thyroid hormones regulate body temperature, the speed of metabolism (how quickly food is changed into energy) and many other functions (National Cancer Institute, 2017).
Some types of thyroid cancer include the following (Glikson, Alon, Bedrin & Talmi, 2017; Resende de Paiva, Grønhøj, Feldt-Rasmussen & von Buchwald, 2017):
Symptoms of thyroid cancer include the following (Cancer Australia, 2017):
The risk factors of thyroid cancer include the following:
The thyroid gland makes thyroid hormones which affect all cells in the body. Thyroid hormones regulate body temperature, the speed of metabolism (how quickly food is changed into energy) and many other functions (National Cancer Institute, 2017).
Some types of thyroid cancer include the following (Glikson, Alon, Bedrin & Talmi, 2017; Resende de Paiva, Grønhøj, Feldt-Rasmussen & von Buchwald, 2017):
- Papillary Thyroid Carcinoma - this is the most common type in about 70-80% of those diagnosed.
- Follicular Thyroid Carcinoma - affects 10-20% of people diagnosed.
- Medullary Thyroid Carcinoma - at 5-8% of patients with thyroid cancer, and often caused by an inherited genetic mutation in the RET gene (National Cancer Institute, 2017).
- Anaplastic Thyroid Carcinoma - affects less than 5% of people diagnosed with thyroid cancer.
- Thyroid Lymphoma - is a rare form accounting for 1-5% of thyroid cancers.
Symptoms of thyroid cancer include the following (Cancer Australia, 2017):
- Swelling or lump in the neck, but not all thyroid lumps or swellings mean cancer
- Difficulty breathing or shortness of breath
- Difficulty swallowing
- A hoarse voice or a cough that does not go away
- Enlarged lymph nodes in the neck.
The risk factors of thyroid cancer include the following:
- Gender - there is a higher incidence of thyroid cancer amongst women, but men tend to have a more aggressive form of the condition. It is suggested that this may be because males do not seek medical attention at an earlier stage of the condition (Glikson, Alon, Bedrin & Talmi, 2017).
- Diet – diets high in processed foods and less fresh vegetables and fruit can increase the risk of thyroid cancer (Yoo, Yu & Choi, 2016). A deficiency of iodine can lead to thyroid cancer (Moore, Panjwani, Gray, Finnerty, Zarnegar & Fahey, 2017). Other studies show excessive iodine intake also can lead to thyroid cancer (Kim et al., 2017).
- Radiation exposure - the thyroid gland is particularly sensitive to the effects of ionising radiation from x-rays, gamma-rays, from medical tests and from medical radiation or environmental exposure such as nuclear accidents seen in Chernobyl and Fukushima. Exposure to even low or moderate levels of radiation can lead to thyroid tumours, by causing oxidative damage, gene mutations, cell death, altering enzyme and metabolic activities, and cancer (Albi et al., 2017).
- Thyroid conditions - chronic inflammation of the thyroid gland, in particular from Hashimoto's thyroiditis, an autoimmune condition causing an underactive thyroid gland, can cause Papillary Thyroid Cancer, the most common type, as well as to Thyroid Lymphoma, due to elevated levels of the Thyroid Stimulating Hormone (TSH) (Resende de Paiva, Grønhøj, Feldt-Rasmussen & von Buchwald, 2017).
- Infections - chronic viral infections can affect thyroid function and even cause thyroid cancer, including Epstein-Barr Virus (EBV), human parvovirus (EBV19), and even the Hepatitis C virus (HCV) which is usually associated with liver cancer (Ferrari, Fallahi, Antonelli & Benvenga, 2017).
- Smoking and alcohol – these lifestyle factors can significantly increase the risk of thyroid cancers, including second-hand or passive smoking (Yoo, Yu & Choi, 2016).
- Vitamin D deficiency – vitamin D is an anti-inflammatory hormone also needed for a strong immune system which can normally destroy damaged or cancer cells and prevent their proliferation into a tumour. Low vitamin D levels can allow cancer cells to be more aggressive in their growth. Studies have shown that having good vitamin D levels can repress thyroid cancer cell growth, tumour size and metastasis (spreading to other organs) (Nettore, Albano, Ungaro, Colao & Macchia, 2017).
- Increased weight and metabolic changes – increasing body mass can increase cancer risk by affecting metabolic hormones (Yoo, Yu & Choi, 2016).
- Genetics – some specific genetic mutations occur in up to 80% of some types of thyroid cancers to cause increased cell division and cancer progression (Moore, Panjwani, Gray, Finnerty, Zarnegar & Fahey, 2017). Having a genetic mutation does not mean that you will get thyroid cancer, as the increased risk depends on environmental and lifestyle factors which are mostly listed above.