Thyroid cancer treatment increasingly tailored to the individual patient

The management of thyroid cancer has changed over the past few decades. In the past, treatment often involved removing the entire thyroid gland, followed by radioactive iodine and lifelong thyroid hormone substitution. Today, the trend is towards a more individualised approach in which treatment is tailored to the patient’s level of risk.

Professor Laszlo Hegedüs from the University of Southern Denmark and Odense University Hospital describes this development together with two US researchers in an invited review article in The New England Journal of Medicine.

The main message is that treatment should be continually adapted to the risk posed by the individual patient’s cancer, the benefits and drawbacks of treatment, and the patient’s own preferences.

Increased diagnostic activity increases the risk of overtreatment

Thyroid cancer encompasses several types of cancer with widely varying prognoses. By far the most common is papillary thyroid cancer, which also has the best prognosis.

For many years, the number of people diagnosed with thyroid cancer has increased. Annually, albeit with geographical variation, around 10–15 in every 100,000 people are diagnosed with thyroid cancer. As one significant explanation doctors have become better at detecting the disease, partly because of the increasing use of ultrasound scan of the neck also for non-thyroid related  conditions.

- We began detecting more cases as ultrasound scans of the neck became more widely used. Many people undergo scans for entirely different reasons than suspicion of thyroid cancer, and this may account for around half of the detected cases, says Laszlo Hegedüs, Professor Emeritus at the Department of Clinical Research at the University of Southern Denmark and Odense University Hospital.

In the Western world, incidence is now declining again. According to Laszlo Hegedüs, this is partly due to clinical guidelines placing greater emphasis on the risk of overdiagnosis – in other words, detecting cancers that might never have caused serious illness.

Treatment may be postponed in some patients

The increased focus on the risk of overdiagnosis has helped change the way thyroid cancer is managed. According to Laszlo Hegedüs, the challenge is to avoid both overtreatment and undertreatment.

- The crucial thing is to make the correct diagnosis and determine the stage of the disease. We then need to look at, not only risk associated with the disease, but the overall situation together with the patient, respecting the   wishes and priorities of our patients. In many cases, treatment can be postponed without worsening the prognosis, says Laszlo Hegedüs.

This may be particularly relevant for selected patients with a relatively small papillary thyroid cancer and no or discrete symptoms. In these cases, active surveillance may be an alternative to immediate treatment. This does not mean simply leaving the disease untreated. The patient is monitored, and treatment can be offered if the disease progresses.

Postponing treatment may be appropriate because treatment itself can have consequences. Surgery can, among other things, lead to an underactive thyroid, changes to the voice, low calcium levels in the blood and bleeding. Radioactive iodine treatment can affect the salivary glands, cause a dry mouth and lead to secondary cancers. Greater awareness of these side effects means that radioactive iodine is now given to fewer patients and often at lower doses than in the past.

- Active surveillance is typically an option when the disease is progressing slowly and the patient wishes to delay treatment. We monitor the disease over time, reclassify disease stage if necessary and revisit the treatment options, particularly if the patient’s condition changes, says Laszlo Hegedüs.

Active surveillance is not the right option for everyone. The review article describes it as an option for carefully selected patients with low-risk disease.

Treatment may need to change over time

A key message of the review article is that risk should not be assessed only once, at the outset. Instead, it should be reassessed throughout the patient’s treatment and follow-up. New information about the disease may therefore mean that the treatment plan needs to be adjusted.

According to Laszlo Hegedüs, doctors and patients should continually consider three questions: How great is the risk posed by the cancer? What are the benefits and drawbacks of treating it now rather than waiting? And what are the patient’s own values, priorities and preferences?

- We need to avoid both undertreatment and overtreatment. To do that, we need to know what type of cancer the patient has and how advanced it is. Patients need to understand their prognosis and the treatment options available to them so that, together, we can decide on the treatment best suited to their situation, says Laszlo Hegedüs.

This risk-adapted approach does not mean that less treatment is always better. For some patients, delaying treatment or choosing a less extensive form of treatment may be appropriate. Others need surgery, with or without post-surgery radioactive iodine, or therapies aiming for specific molecular targets. The key is to tailor treatment more closely to the individual patient’s disease and to adjust it as necessary over time.