Thyroid cancer

About thyroid cancer

Thyroid cancer develops when the cells of the thyroid grow and divide in an abnormal way. The thyroid is a butterfly-shaped gland found at the front of the neck and just below the voice box.

It is part of the endocrine system, which is a group of glands that makes and controls the body’s hormones.

About 2,900 people are diagnosed with thyroid cancer each year in Australia. It affects almost 3 times as many women as men and can occur at any age. Thyroid cancer is the seventh most common cancer affecting Australian women of all ages, and the most common cancer diagnosed in women aged 20 to 24.

Types of thyroid cancer

There are several types of thyroid cancer. It is possible to have more than one type at once, although this is unusual. Common types of thyroid cancer include:

• papillary (about 70 to 80% of all thyroid cancer cells) – develops from the follicular cells and tends to grow slowly
• follicular (about 10%) – develops from the follicular cells and includes Hürthle cell carcinoma, a less common subtype.

Rarer types of thyroid cancer include:

• medullary (about 6%) – develops from the parafollicular cells (C-cells). It can run in families and may be associated with tumours in other glands
• oncocytic (about 3%) – develops from thyroid follicles. Also known as oxyphilic or Hürthle cell carcinoma.
• anaplastic (about 1%) – may develop from papillary or follicular thyroid cancer. It tends to grow quickly and usually occurs in people over 60 years old.

Symptoms of thyroid cancer

Thyroid cancer usually develops slowly, without many obvious symptoms. However, some people experience one or more of the following:

• a painless lump in the neck (the lump may grow gradually)
• trouble swallowing
• difficulty breathing
• changes to the voice
• swollen lymph glands (lymph nodes) in the neck (the lymph nodes may slowly grow in size over months or years).

Although a painless lump in the neck is a typical sign of thyroid cancer, thyroid lumps are common and turn out to be benign in 90% of adults. Having an underactive or overactive thyroid is not typically a sign of thyroid cancer.

Not everyone with these symptoms has thyroid cancer. If you have any of these symptoms or are worried, always see your doctor.

Risk factors for thyroid cancer

There are some things that can make it more likely to develop thyroid cancer. These are called risk factors and they include:

• Exposure to radiation – a small number of thyroid cancers are due to having radiation therapy to the head and neck area as a child or living in an area with high levels of radiation.
• Family history – only around 5% of thyroid cancer runs in families. Some inherited genetic conditions, such as familial adenomatous polyposis or Cowden syndrome, or inheriting the RET gene may also increase your risk.
• Other factors – people who are overweight or obese possibly have a higher risk of developing thyroid cancer. Other thyroid conditions only slightly increase the chance of developing thyroid cancer.

Having these risk factors doesn’t mean you will develop thyroid cancer. Often there is no clear reason for getting thyroid cancer. If you are worried about your risk factors, ask your doctor for advice.

Tests for thyroid cancer

Your doctor may do some tests to check for thyroid cancer:

• Ultrasound – to get detailed information about your thyroid including the size of any thyroid nodule and whether it is full of fluid or solid.
• Blood tests – to check your hormone levels and function of the thyroid. Calcitonin levels may also be checked.
• Biopsy – if you have a thyroid nodule or enlarged lymph node in your neck, you may need a fine needle aspiration (FNA) biopsy, to collect a sample of cells and check whether it is cancerous.

Your doctor might ask you to have further tests. These can include:

• CT scans – uses x-rays to take pictures of the inside of your body and then compiles them into one detailed, cross-sectional picture.
• PET scans – uses an injection of a glucose (sugar) solution to help cancer cells show up more brightly on the scan.

Stages of thyroid cancer

Stages

The stage of a cancer means how far it has grown in your body. In many cases, the information needed for accurate staging is available only after surgery. The most common way doctors decide on a stage for thyroid cancer is the TNM system (tumour-nodes-metastasis). This system describes:

• if the cancer is smaller and remains inside the thyroid or if it is larger and has spread to other parts of the neck
• if the cancer has spread to nearby lymph nodes
• if the cancer has spread to other parts of the body, such as the lungs or bones.

Ask your doctor or nurse to explain the stage of the cancer. You can read more from Cancer Council about diagnosing thyroid cancer.

Prognosis and survival rates for thyroid cancer

When someone is diagnosed with thyroid cancer, their doctor will give them a prognosis. A prognosis is the doctor’s opinion of how likely the cancer will spread and the chances of getting better. A prognosis depends on the type and stage of cancer, test results and a person’s age, fitness and medical history.

The most common types of thyroid cancer have an excellent long-term prognosis, especially if the cancer is found only in the thyroid or nearby lymph nodes in the neck. Even if the cancer has spread, the outcome can still be good.

Doctors commonly use 5-year survival rates as a way to discuss prognosis. This is because research studies often follow people for 5 years – it does not mean you will survive for only 5 years. Thyroid cancer has a very high 5-year survival rate (97%).

If you have thyroid cancer, your doctor will talk to you about your individual situation when working out your prognosis. Every person’s experience is different, and there is support available to you.

Treatment for thyroid cancer

The type of treatment your doctor recommends will depend on the type and stage of the thyroid cancer, and your age and general health.

Active surveillance

Your doctor may recommend closely monitoring the cancer, rather than having treatment straightaway. This is known as active surveillance and it usually involves regular ultrasounds and physical examinations.

There is good evidence that active surveillance is safe for small papillary thyroid cancers where there is no sign that the cancer has spread from the thyroid.

Some people choose to have active surveillance if the possible side effects from treatment would have more impact on their quality of life than the cancer itself. Other people find that active surveillance makes them feel anxious and prefer to have treatment straightaway.

Treatment can be considered at any stage if you change your mind or if the cancer grows or spreads.

Surgery

Surgery is the most common treatment for thyroid cancer. You will be given a general anaesthetic, and the surgeon will make a small cut (5 to 7 cm) across your neck.

How much tissue is removed will depend on how far the cancer has spread:

• Partial thyroidectomy – only the affected lobe or section of the thyroid is removed.
• Total thyroidectomy – most people with thyroid cancer need to have a total thyroidectomy. This involves removing the whole thyroid.
• Lymph node removal – nearby lymph nodes may also be removed.
• Other tissue – in very rare cases, the surgeon also removes other tissue near the thyroid that has been affected by the cancer.

Thyroid hormone replacement therapy

Many people who have a partial thyroidectomy won’t need thyroid hormone replacement therapy because the remaining lobe will continue to make enough hormones.

After the whole thyroid is removed, your body will no longer produce the hormones that maintain your metabolism, and you will be prescribed a hormone tablet.

Taking thyroid hormone tablets can keep your body’s metabolism functioning at a normal healthy rate and reduce the risk of the cancer coming back.

Radioactive iodine treatment

Radioactive iodine (RAI) is a type of radioisotope treatment. Radioisotopes are radioactive substances given in a pill that you swallow. Although RAI spreads through the body, it is mainly absorbed by thyroid cells or thyroid cancer cells. RAI kills these cells while leaving other body cells relatively unharmed.

You may be given RAI to destroy tiny amounts of remaining cancer cells or healthy thyroid tissue left behind after surgery. It is usually recommended for papillary or follicular thyroid cancers that have spread to the lymph nodes or that have a higher risk of coming back after surgery.

RAI is generally not given until some weeks after surgery, once any swelling has gone down. This is because swelling can affect the blood flow and stop the RAI circulating well. You will need to stay in hospital for 36 to 48 hours in an isolated room to safely contain the radioactivity.

Targeted therapy

Targeted therapy drugs attack specific features of cancer cells to stop the cancer growing and spreading. The most common drugs used for thyroid cancer are tyrosine kinase inhibitors (TKIs).

If you have advanced thyroid cancer that hasn’t responded to RAI treatment, you may be offered a TKI such as lenvatinib. These drugs are given as a tablet, which you take daily. Other TKIs may be available on clinical trials.

External beam radiation therapy

External beam radiation therapy (EBRT) uses a controlled dose of radiation to kill cancer cells or damage them so they cannot grow, multiply or spread.

Most people diagnosed with thyroid cancer do not need EBRT, but it may be recommended in particular circumstances. In a small number of cases, it may be given:

• after surgery and RAI treatment if the cancer has not been completely removed or if there is a high risk of the cancer returning (recurrence)
• as palliative treatment to relieve symptoms such as pain caused by cancer that has spread to nearby tissue or structures
• to help control medullary or anaplastic thyroid cancer (because these types do not respond to RAI).

Radiation therapy is usually given 5 days a week over several weeks. You may be fitted for a plastic mask to wear during treatment, which will help you stay still so that the radiation is targeted at the same area of your neck during each session.

Chemotherapy

Chemotherapy is the use of drugs to kill cancer cells or slow their growth. While chemotherapy is not often used to treat thyroid cancer, it may sometimes be used to treat advanced thyroid cancer that is not responding to RAI treatment or targeted therapy.

It may also be used in combination with radiation therapy to treat anaplastic thyroid cancer. The drugs are usually given by injection into a vein. The number of treatment sessions and length of treatment time varies from person to person.

Immunotherapy

Immunotherapy is a type of drug treatment that uses the body’s own immune system to fight cancer. Talk to your specialist to find out more about new treatments and clinical trials.

Side effects of thyroid cancer treatment

All cancer treatments can have side effects. Your treatment team will discuss these with you before you start treatment. Talk to your doctor or nurse about any side effects you are experiencing. Some side effects can be upsetting and difficult, but there is help if you need it. Call Cancer Council Tel. 13 11 20 or contact cancer support to speak with a caring cancer nurse.

Managing lifestyle changes from thyroid cancer

Fertility concerns

Many people diagnosed with thyroid cancer are under 40 and may be concerned about how the treatment will affect their ability to conceive a child. Fertility usually is not permanently affected by surgery or radioactive iodine treatment. In the short term, it is recommended that you delay pregnancy for 6 months after treatment.

If you or your partner want to have a baby after RAI treatment, talk to your doctor. RAI may have a short-term effect on eggs and sperm, so you’ll be advised to use contraception for a set amount of time. Women also need to check that their thyroid hormone levels are normal before trying to get pregnant.

Sexuality

Having thyroid cancer and treatment can change the way you feel about yourself, other people, relationships and sex. These changes can be very upsetting and hard to talk about. Doctors and nurses are very understanding and can give you support. You can ask for a referral to a counsellor or therapist who specialises in body image, sex and relationships.

Living with advanced cancer

Advanced cancer usually means cancer that is unlikely to be cured. During this time palliative care services can help. Most people with thyroid cancer respond well to treatment and do not need to access palliative care services. However, people at any stage of advanced thyroid cancer may benefit from palliative treatment.

Most people continue to have treatment for advanced cancer as part of palliative care, as it helps manage the cancer and improve their day-to-day lives. Many people think that palliative care is for people who are dying but palliative care is for any stage of advanced cancer. There are doctors, nurses and other people who specialise in palliative care.

Treatment may include chemotherapy, radiation therapy or another type of treatment. It can help in these ways:

• Slow down how fast the cancer is growing.
• Shrink the cancer.
• Help you to live more comfortably by managing symptoms, like pain.

Treatment depends on:

• where the cancer started
• how far it has spread
• your general health
• your preferences and what you want to do.

Ask your doctor about treatment and palliative care services that may help you.

Support for carers, family and friends

Caring for someone with cancer can be difficult sometimes. If you are caring for someone with thyroid cancer, these organisations can help:

• Cancer Council – Information and support line Tel. 13 11 20 (or 13 14 50 for an interpreter)
• Carer Gateway Tel. 1800 422 737
• Carers Australia Tel. 1800 422 737

Where to get help

• Your GP (doctor)
• Cancer Council
  • Information and support line Tel. 13 11 20 (or 13 14 50 for an interpreter)
  • Understanding thyroid cancer
  • Podcasts
  • Fertility
  • Sexuality and intimacy
  • Cancer Council Victoria, My Cancer Guide - Find support services that are right for you.
• NURSE-ON-CALL Tel. 1300 606 024
• The Australian Thyroid Foundation Tel. 0447 834 724
• Australian and New Zealand Endocrine Surgeons