Thyroid cancer

The thyroid is a small organ at the front of the neck, just below the Adam's apple. It makes the hormones that set the pace of the metabolism: heart rate, body temperature, weight, the workings of the bowel, mood and the ability to concentrate all depend on them. Thyroid cancer is uncommon, three or four times more frequent in women than in men, and it usually begins as a painless lump in the gland. People rarely read a page like this out of curiosity: either a scan has found a nodule or the diagnosis has already been said out loud. So let us begin with the thing that, in this illness, tends to be said far too late.

The main point: most forms do extremely well

The word cancer sounds equally frightening whatever the organ, but the outlook differs enormously from one tumour to another, and thyroid cancer is among the most favourable of all. The great majority of cases are the papillary and follicular types; they are called differentiated because their cells largely keep the properties of normal thyroid tissue. They grow slowly, respond well to treatment, and most people go on to live an entirely ordinary life afterwards — with follow-up and a daily tablet, but with no restrictions on work, sport, pregnancy or travel.

Other types are rarer. Medullary cancer arises from different cells in the gland, is sometimes inherited and calls for relatives to be tested. Anaplastic cancer is a rare, fast-growing form that occurs mainly in older people and is managed quite differently. That is why the type of tumour and its stage matter far more than the word cancer itself: until they are known, statistics found online do not apply to your situation. And there is usually no need to rush decisions — differentiated thyroid cancer grows slowly, and a few weeks for tests, a second opinion and an unhurried conversation with the surgeon will spoil nothing.

A thyroid nodule is a very common finding

The first thing most people meet is a nodule, and here it helps to grasp the scale. Thyroid nodules are present in a very large proportion of adults, particularly women and particularly with age. Ultrasound finds them in something like one adult in two or three over fifty, and most often entirely by accident, during a scan of the neck vessels, an image of the spine or an investigation for something else altogether.

The overwhelming majority of nodules are benign. Only a small share turn out to be cancer. That does not mean a nodule can be ignored, but it does mean that finding one is no reason to consider yourself a cancer patient before any investigation has been done.

It is also worth knowing that hormone blood tests settle very little here. In thyroid cancer the hormone levels are usually normal, and a normal TSH does not rule a tumour out. The reverse also holds: a nodule that pours out hormone of its own, a so-called hot nodule, is almost never malignant. Good blood results are good news, but they are not the answer to the question.

What should prompt attention

Most nodules announce themselves in no way at all. But there are features that mean investigation should not be put off. None of them means cancer — every one occurs with benign conditions too — but each needs checking.

• A lump or swelling in the neck that has visibly grown over weeks or months.
• A lump that feels firm, hard and does not move, as though fixed to the surrounding tissue.
• Hoarseness or a change in the voice lasting more than three weeks without a cold to explain it.
• Difficulty swallowing, a sense of a lump or pressure in the throat, and all the more so difficulty breathing.
• Enlarged lymph nodes in the neck, especially if they are firm, painless and persistent.
• A nodule in a child, a teenager or a young adult — nodules are less common at that age, and the chance that one is a tumour is higher.
• Radiation to the neck in the past, above all in childhood: radiotherapy, or exposure after a nuclear accident.
• Thyroid cancer in a close relative, or a known inherited syndrome in the family.

A word on persistent hoarseness. It arises when a tumour involves the nerve that works the vocal cord, and it is the symptom most often put down to having strained the voice and then waited out for months. A voice that has not recovered in three weeks is a reason to be seen, whether or not there is a lump in the neck.

How a nodule is actually checked

A nodule is not kept an eye on and not judged by feel. The order of investigation is settled and much the same everywhere.

• A blood test for TSH, to see how the gland is working and not to miss a hot nodule.
• Ultrasound of the thyroid and of the neck lymph nodes, which is the mainstay. The radiologist looks at far more than size: the shape of the nodule, its internal structure, how sharp its borders are, tiny specks of calcium, the pattern of blood flow. Taken together these place the nodule in a risk category, and it is the category that decides whether a biopsy is needed.
• Fine-needle aspiration biopsy — cells are drawn from the nodule with a thin needle under ultrasound guidance. It is done as an outpatient, without anaesthetic, feels much like an ordinary blood test and takes a few minutes.

Not everyone needs a biopsy: a small nodule without worrying features is simply looked at again on ultrasound after an interval. That is a reasoned approach, not a brush-off.

A biopsy result may be benign, suspicious, malignant or, quite often, indeterminate, when there were too few cells or the picture sits in between. An indeterminate result does not mean cancer: the biopsy is usually repeated, or removing one lobe of the gland is discussed in order to get an answer. If the diagnosis is confirmed, a scan and an examination of the vocal cords with a thin flexible endoscope passed through the nose may follow.

Surgery, and what comes after it

The main treatment is an operation. Depending on the type and extent of the tumour, either one lobe or the whole gland is removed; if lymph nodes are involved they are taken out at the same time. The incision is made in a natural crease of the neck and the scar becomes inconspicuous with time.

There are two consequences that are much better known about beforehand than met unexpectedly.

The voice. The nerves that operate the vocal cords run right beside the thyroid. Even with careful surgery the voice is often hoarse afterwards, weaker or quick to tire, with the upper range gone. In most cases this is temporary and settles over weeks or months, and work with a speech therapist helps. Anyone whose voice is a working tool should raise it with the surgeon in advance.

Calcium. Pressed against the thyroid are four tiny parathyroid glands, which control the level of calcium in the blood. After surgery they may stop working for a while and the calcium falls. This shows itself very characteristically: tingling and numbness in the fingertips and around the mouth, cramps in the hands, twitching muscles. That is why calcium is measured after the operation and why calcium and vitamin D are so often prescribed. Function usually returns, though sometimes the supplements have to continue for a long time. If these sensations appear once you are home, contact a doctor the same day; with cramping of the hands and feet, spasm of the face muscles or difficulty breathing, call an ambulance — in Spain, Italy, Portugal, Poland and Ukraine that is the single European number 112.

An ambulance is needed in one other situation: if in the first hours or days after the operation the neck swells quickly, feels tight and full, and breathing becomes difficult. Those are signs of bleeding beneath the wound and they need help immediately.

Radioactive iodine and the other treatments

After the whole gland has been removed, some people are given radioactive iodine. Thyroid cells, normal and cancerous alike, take up iodine avidly, and radioactive iodine destroys from within any that may have been left behind. It is taken as a capsule or a drink, preceded by a few weeks on a low-iodine diet. For several days close contact with other people has to be limited, especially with children and pregnant women; the rules vary by country and by hospital. Side effects are usually modest: a dry mouth, altered taste, swollen salivary glands.

It is by no means needed by everyone. For a small tumour with favourable features it is now increasingly left out, and that is not cost-cutting but the result of studies showing no benefit in such cases. The other treatments are used less often and mainly in advanced or rare forms: targeted drugs and external beam radiotherapy. Chemotherapy is seldom used in thyroid cancer and is not a mainstay of treatment.

The tablet afterwards: replacement, not chemotherapy

This is where the commonest misunderstanding arises, the one that leads people to stop treatment on their own. After the gland is removed, thyroid hormone is prescribed as a tablet, levothyroxine. This is not chemotherapy, and not "hormones" in the sense people have learned to be wary of. It is exactly the same substance the gland used to make; the tablet simply takes its place. Without it the body is left with no thyroid hormone at all, and that is a serious state: mounting weakness, puffiness, feeling cold all the time, slowed thinking, weight gain and, if allowed to go far enough, danger to life.

So doses must not be skipped, and taking a break to give the body a rest from medicines is not possible here even in principle. A correctly adjusted dose produces no side effects at all: on it, people feel as they did before they were ill.

A few practical things that make life easier:

• The tablet is taken in the morning on an empty stomach with water, leaving about half an hour before eating. Taking it in the evening is also possible if that suits better — what matters is regularity.
• Iron, calcium and magnesium supplements and indigestion remedies interfere with absorption. Space them several hours apart from the levothyroxine.
• The dose is set by a blood test rather than by how you feel, and it is changed only on medical advice. Different manufacturers are not always interchangeable, so the blood test is repeated after a switch.
• In pregnancy the need for the hormone rises, and the dose is reviewed early, as soon as the pregnancy is confirmed.
• If you miss a day, take the tablet as soon as you remember; there is no need to double up the next day.

Follow-up continues for years after treatment: blood tests, including thyroglobulin in those who had the whole gland removed, and ultrasound of the neck. Its purpose is not only to catch any return of the disease but also to keep the hormone dose right, so the review appointments are worth keeping even when everything is going well.

Online consultation

A large part of what people need with this diagnosis calls for no examination at all: what is wanted is somebody who will calmly explain what the reports say. An online consultation suits that well.

In a consultation a doctor will go through the ultrasound description and the risk category of the nodule, explain whether a biopsy is needed or a repeat scan will do, and what the cytology wording means for the next steps. They will go through the TSH results and the levothyroxine dose, help you build a list of questions for the surgeon and, after an operation, help you judge whether what you are feeling belongs to ordinary recovery or means being seen in person.

What an online consultation does not replace: examination of the neck, ultrasound, biopsy and the treatment itself; and with difficulty breathing, a rapidly swelling neck or cramps after surgery, calling an ambulance.

This material is for information only and does not replace medical advice.