Thyroid cancer: symptoms, risk factors, tests and treatment

Many of the symptoms linked to thyroid cancer have other causes. Still, knowing the signs helps you act early. This article describes the types, symptoms, risk factors, tests and treatments, using information from the NHS and the US National Cancer Institute (NCI).

1. Introduction

The thyroid is a gland at the front of the neck that makes hormones. The NHS describes thyroid cancer as cancer found in this gland ^[1]. The NCI describes well-differentiated cancers (papillary and follicular), medullary cancer, which starts in the thyroid's C cells, and anaplastic cancer ^[5]. Anaplastic cancer grows and spreads quickly and has a poorer chance of recovery ^[5].

2. Signs and symptoms

The NHS lists these symptoms ^[1]:

• A hard, slow-growing, painless lump at the front and lower part of the neck
• Hoarseness
• A sore throat
• Trouble swallowing or breathing
• Pain at the front of the neck, or a sense of pressure there

The NHS also lists flushing (a red face), softer stools or diarrhoea, weight loss and a cough ^[1]. The NCI notes that early thyroid cancer often causes no symptoms and may be found during a routine exam ^[5].

These symptoms are common and have many causes, so they do not confirm cancer ^[1]. People with an existing thyroid condition, such as a goitre (enlarged thyroid), should still see a doctor if symptoms change or get worse ^[1].

3. Causes and risk factors

The cause is not always clear, and the NHS says anyone can get thyroid cancer ^[2]. The NHS and NCI list these factors that may raise risk ^{[2, 5]}:

• Being female, and for the NHS, being a woman who has not yet gone through menopause
• Existing thyroid conditions, such as goitre, Hashimoto disease or non-cancerous thyroid lumps (nodules)
• A parent, brother, sister or child with thyroid cancer
• Past exposure to high levels of radiation or radiotherapy, especially in childhood
• Certain inherited conditions, including a type linked to medullary cancer ^[5]

The NHS says thyroid cancer cannot always be prevented, but being a healthy weight, keeping alcohol within the recommended limit and not smoking may lower the risk of this and other cancers ^[2].

4. Diagnosis and tests

A GP may examine your neck and arrange a blood test, and may refer you urgently to a specialist if cancer is possible. A referral does not mean you have cancer ^[1]. The NHS says initial hospital tests may include ^[3]:

• Blood tests
• An ultrasound scan of the neck
• A biopsy, where a needle takes a small sample from the thyroid to be checked for cancer

Results usually take about 2 weeks ^[3]. If cancer is found, scans such as CT, MRI or PET, and a check of the vocal cords with a thin camera tube, help show the size of the cancer and how far it has spread, which is called staging ^[3]. The NCI also lists tests for calcium and for a hormone called calcitonin, which is used for medullary cancer ^[5].

5. Treatment

The NHS says treatment depends on the size and type of cancer, whether it has spread and your general health, and that your specialist team will explain the benefits and side effects of each option ^[4]. Main options include ^{[4, 5]}:

• Surgery: the most common treatment. This may remove the whole thyroid (total thyroidectomy) or part of it (lobectomy), and sometimes nearby lymph nodes.
• Thyroid hormone tablets: after the whole thyroid is removed, tablets replace the hormones it made, and they can also help lower the risk of the cancer returning. You may need them after partial removal too ^[4].
• Radioactive iodine: a tablet or drink containing a small amount of radiation that may be given after surgery to destroy remaining cancer cells, or if the cancer returns or spreads ^[4].
• Targeted medicines and radiotherapy: used in particular situations, for example when other treatments are not suitable or the cancer has spread. Chemotherapy is not usually used but may be considered if the cancer returns or spreads ^[4].
• Watchful waiting: the NCI notes that close monitoring without treatment is an option in some cases ^[5].

The NHS says advanced thyroid cancer can be hard to treat, in which case treatment aims to limit the cancer and its symptoms and a palliative care team can support comfort ^[4].

6. Follow-up and outlook

You will have regular check-ups, tests and scans during and after treatment. Report worrying symptoms or side effects promptly instead of waiting for the next appointment ^[4]. The NCI says outlook depends on age, cancer type and stage, and whether surgery removed all the cancer, and that well-differentiated cancers (papillary and follicular) can usually be treated successfully ^[5].

7. When to see a doctor

The NHS advises a non-urgent GP appointment for a new neck lump or one that is getting bigger, for hoarseness, a sore throat or a cough lasting more than 3 weeks, or for pain or pressure at the front of the neck ^[1]. Seek urgent help if you have difficulty swallowing or breathing ^[1].

In an emergency, call your local emergency number (112 in India, 911 in the United States).

8. Conclusion

Thyroid cancer often shows as a painless neck lump, but most neck symptoms have other causes. Early checks matter because finding cancer early may make it easier to treat. Tests such as ultrasound and biopsy confirm the diagnosis, and your specialist team plans treatment, usually including surgery, to suit you.