The number of people diagnosed with thyroid cancer in England has doubled since the early 1990s, according to a new report published by the National Cancer Intelligence Network (NCIN) today (Friday).
Between 1990 and 1994 around 900 people (1.7 per 100,000 people) were diagnosed with thyroid cancer every year in England. By 2006-10 this figure increased to 1,950 (3.4 per 100,000 people). But, thanks to effective treatments, survival rate have remained high, at around 90 per cent.
Researchers from the Oxford Cancer Intelligence Unit found that most of this increase has been seen in a particular type of thyroid cancer called papillary cancer. This form of the disease has the best prognosis.
The rise has been linked to increased diagnosis of the disease through better techniques such as ultrasound and fine needle biopsies that can pick up much smaller cancers and possibly a 'real' rise in the number of people developing thyroid cancer.
Mr David Chadwick, consultant endocrine surgeon at Chesterfield Royal Hospital and Chair of the NCIN Thyroid Working Group, said: "The exact reason behind this steep rise in thyroid cancer cases remains unclear. We now have more sensitive diagnostic techniques so it could be that more cancers are being picked up when patients are being tested for other conditions. And, this could mean that we're detecting and treating some cancers that would otherwise not have shown up during a person's life.
"We may also be seeing a 'real' increase in the incidence of thyroid cancer, some of which may be due to improved long-term survival of other cancers previously treated with radiotherapy to the neck or chest. Sadly, older forms of radiotherapy had a side-effect that increased the risk of other cancers later in life."
The report also showed that thyroid cancer is three times more common in women than in men. For men and women one year survival rates had increased, by nine per cent for men to 88.3 per cent and by 15 per cent for women to 94.3 per cent.
Unlike most cancers, thyroid cancer is most often picked up in people aged between 20 and 59, particularly for the papillary form of the disease, with those aged 30 and 54 having the highest rates.
Treatment for thyroid cancer most commonly includes surgery to remove the thyroid and is often followed up with radioactive iodine. This acts as a 'targeted treatment' as the iodine is only taken up by thyroid cancer cells, ultimately killing them.
While this treatment approach has meant that most people with thyroid cancer are successfully treated, there are some forms of the disease that have a very poor prognosis.
Currently, it is difficult for doctors to predict the behaviour of thyroid cancer in an individual patient, which means that most patients will require thyroid surgery.
Chris Carrigan, head of the National Cancer Intelligence Network (NCIN), said: "This increase in the number of people being diagnosed with thyroid cancer reflects a trend that we're seeing in other countries. While thyroid cancer is generally a very treatable disease, there is a lot we don't understand about it. We need to better understand the different forms of the disease so that doctors can predict which patients need more aggressive treatment and which don't."