Follicular thyroid cancer: symptoms, tests, treatment and follow-up in the UK

The thyroid is a small gland at the front of the neck that makes hormones controlling how the body uses energy. Cancer Research UK explains that the type of thyroid cancer depends on the type of cell the cancer starts in. There are two main cell types in the gland: follicular cells, and C cells that make calcitonin. Most thyroid cancers start in follicular cells.

Follicular thyroid cancer is one of three differentiated cancers that arise from follicular cells, the others being papillary thyroid cancer and oncocytic (Hurthle cell) thyroid cancer. Differentiated means the cancer cells still look a lot like normal thyroid cells under the microscope. Cancer Research UK describes papillary cancer as the most common type, so follicular cancer is the less common of the two main differentiated types.

Oncocytic thyroid cancer used to be grouped with follicular thyroid cancer because the two share some similarities, but the cells look different and it is now described separately. Pathologists also grade thyroid cancers. Cancer Research UK says some follicular-derived cancers are high grade, with features such as many dividing cells or areas of dying tissue, and these rarer cancers tend to grow more quickly and may call for more intense treatment and closer follow-up.

The NHS describes the main symptoms of thyroid cancer in general rather than by type, so these apply to follicular cancer too. Many people have no symptoms for a long time, and the first sign is often a lump that someone notices in the neck.

• A lump in the front, lower part of the neck, which usually feels hard, slowly gets bigger and is not painful.

• A hoarse voice, a sore throat or a cough.

• Difficulty swallowing or breathing.

• Pain in the front of the neck, or a feeling that something is pressing against it.

The NHS advises seeing a GP if you have a new lump in your neck or an existing lump that is getting bigger, if you have had a hoarse voice, sore throat or cough for more than 3 weeks, or if you have pain in the front of your neck or a feeling of pressure there.

It also says to ask for an urgent GP appointment or get help from NHS 111 if you are having difficulty swallowing or breathing. These symptoms are very common and have many causes, so having them does not mean you have thyroid cancer, but finding a cancer early may make it easier to treat.

If you already have a thyroid condition such as a goitre, the NHS notes you might get used to symptoms like these. It is still important to be checked if they change, get worse or no longer feel normal for you.

The NHS says it is not always clear what causes thyroid cancer, and anyone can get it. It lists several things that can make it more likely: being a woman who has not been through the menopause, having a thyroid condition such as a goitre, Hashimoto's disease or nodules, having a brother, sister, parent or child who has had thyroid cancer, and past exposure to a lot of radiation or radiotherapy, especially in childhood. Some previous cancers, including breast, oesophageal and testicular cancer and non-Hodgkin lymphoma, are also listed.

The NHS adds that many thyroid cancers are also linked to lifestyle. It suggests trying to lose weight if you are overweight, cutting down on alcohol (avoiding more than 14 units a week) and trying to quit smoking, while noting that thyroid cancer cannot always be prevented.

At the GP appointment the NHS says the GP may feel your neck and might arrange a blood test. If the GP thinks your symptoms could be cancer you may get an urgent referral to a specialist, which does not definitely mean you have cancer.

In hospital the main tests listed by the NHS are blood tests, an ultrasound scan of the neck and a biopsy, where a small sample is taken from the thyroid with a needle and checked for cancer. You may not have all of them. The NHS says it should take about 2 weeks to get results, though it can take longer, and that delay does not necessarily mean anything is wrong.

If thyroid cancer is confirmed you will usually need more tests to find the size of the cancer and how far it has spread. The NHS says these can include CT, MRI or PET scans and a test using a thin flexible camera passed through the nose to check the vocal cords. A specialist team looks after you, including a clinical nurse specialist who is your main point of contact.

Pathology also decides the type. Cancer Research UK says a specialist doctor examines a sample of thyroid cells under the microscope and looks at the cell of origin, how abnormal the cells look and any gene changes in the tumour. It describes the number stages for papillary and follicular thyroid cancer as the same system, which differs from the system used for medullary and anaplastic cancers.

The NHS says thyroid cancer is often treatable and that treatment depends on the size and type of the cancer, whether it has spread and your general health. It usually includes surgery, and may also include hormone therapy, radioactive iodine treatment, targeted medicines, radiotherapy or chemotherapy.

Surgery is the most common treatment. Depending on type and stage, you may have all of the thyroid removed (total thyroidectomy) or part of it removed (partial thyroidectomy or lobectomy). Some lymph nodes in the neck may be removed as well if the cancer has or might have spread to them. Cancer Research UK adds that problems after surgery can include changes to the voice and to thyroid hormone and calcium levels.

If the whole thyroid is removed you usually need to take hormone tablets to replace the hormones it made, which the NHS says can also help stop the cancer coming back. Radioactive iodine, taken as a tablet or drink, may be used after surgery to kill any cancer cells left behind or to help stop the cancer returning, and if the cancer has come back or spread. Targeted medicines are used if other treatments are not an option or no longer working, radiotherapy if the cancer cannot be removed by surgery or has spread, and chemotherapy is not usually used unless the cancer has come back or spread.

After treatment you have regular appointments. Cancer Research UK says these may be every few months at first and then every six months or every year, and become less frequent over time. How long they continue depends on the chance of the cancer coming back: at least 5 years for low risk, at least 10 years for intermediate risk and life for high risk.

Checks can include blood tests for thyroid hormone levels, calcium levels if the parathyroid glands were removed or damaged, and the tumour marker thyroglobulin, which applies to papillary and follicular cancers. Cancer Research UK says a rising level does not always mean the cancer has come back, so other tests such as an ultrasound of the neck are arranged if levels are abnormal. Results from the specialist laboratory may take up to 4 weeks.

You do not have to wait for the next appointment if you notice new symptoms or are worried. The NHS says to talk to your specialists about any symptoms or side effects. Macmillan Cancer Support and Cancer Research UK both run helplines for support.

Thyroid cancer is normally managed by a specialist multidisciplinary team within the NHS, from urgent GP referral through diagnosis, surgery and long-term follow-up. Some people also see a private endocrine or head and neck specialist for assessment or surgery; the type of cancer, staging and treatment decisions are broadly the same, and your NHS GP can usually share records and continue follow-up.