Thyroid cancer: a calm overview

What thyroid cancer is

Thyroid cancer is an abnormal growth of cells within the thyroid gland. Like all cancers, it begins when cells divide and multiply in an uncontrolled way - but the thyroid is the starting point, not another part of the body.

It is not a single disease. There are several types, each with different behaviour and outlook. Understanding which type you have is an important early conversation with your specialist team.

The main types

Papillary thyroid cancer is by far the most common, accounting for about 8 in 10 (80%) of cases. It tends to grow slowly and is most often found in younger adults and women. Even when it has spread to nearby lymph nodes, the long-term picture for most people is good.

Follicular thyroid cancer is the second most common type. It is more likely to spread through the bloodstream to distant sites, but most people are diagnosed before this happens.

Medullary thyroid cancer arises from different cells (C-cells) that produce calcitonin rather than thyroid hormone. It can be sporadic or inherited. A different set of markers and specialist pathways are involved.

Anaplastic thyroid cancer is rare and behaves very differently from the differentiated types above. It is aggressive and requires rapid specialist management.

Papillary and follicular thyroid cancers are grouped together as differentiated thyroid cancer (DTC). Most of the information below applies to DTC - which accounts for the great majority of diagnoses.

The typical treatment path for differentiated thyroid cancer

Treatment varies depending on the type and stage of cancer, and your team will tailor it to your situation. A common path for DTC looks like this:

• Surgery - usually a total thyroidectomy (removal of the entire thyroid). For smaller, lower-risk tumours a hemithyroidectomy (removal of one lobe) may be sufficient.
• Radioactive iodine (RAI) - not everyone needs this, but it is often used after surgery to destroy any remaining thyroid tissue and microscopic cancer cells. It exploits the fact that thyroid cells absorb iodine uniquely. See radioactive iodine.
• Levothyroxine - because the thyroid has been removed, you will need lifelong thyroid hormone replacement. For some people, the dose is set to keep TSH below the normal range - sometimes well below it - to reduce stimulation of any residual cancer cells. For lower-risk cancers the aim may be nearer the normal range instead. Your team will explain the target that is right for you, and may adjust it over time.
• Monitoring - regular blood tests, including thyroglobulin (a marker specific to thyroid tissue), TSH, and sometimes imaging. This is how your team keeps an eye on the situation over the long term.

Outcomes for differentiated thyroid cancer

Your specialist team is best placed to give you a realistic picture for your specific situation - the range of outcomes varies with type, stage, and individual factors that only they can assess.

For papillary and follicular thyroid cancers detected at an early stage, the long-term outlook is generally very good - among the best of any cancer. Many people live for decades after treatment without recurrence.

This is not meant to minimise what you are going through. A cancer diagnosis is frightening, and the treatment path - surgery, possible RAI, lifelong medication, and ongoing surveillance - is a significant thing to live with. Those feelings are real and valid.

What it means is that the medical picture, for most people with DTC, is a manageable one.

Your multidisciplinary team

Thyroid cancer is managed by a specialist multidisciplinary team (MDT) - typically including a head and neck or endocrine surgeon, an endocrinologist, a nuclear medicine physician (if RAI is involved), a specialist nurse, and a pathologist. This team reviews your case together and agrees a plan. If you are unsure who to contact about something, your specialist nurse is usually the best first call.

Questions worth asking

Use the questions tool to build a list before your appointments. Some starting points:

• What type of thyroid cancer do I have, and what does that mean for my treatment?
• Do I need a total thyroidectomy, or might a partial operation be appropriate?
• Will I need radioactive iodine? What does that involve, and how long will I need to isolate?
• What will my levothyroxine dose be, and how will my TSH target be managed?
• How will I be monitored after treatment, and for how long?
• Who is my key contact if I have concerns between appointments?