The new study would inform of clinical guidelines on appropriate treatment for differentiated thyroid cancer and also help educate the public about the condition.

Doctors around the world are over diagnosing the most common thyroid cancer, creating an artificial epidemic that costs billions of dollars each year in unnecessary medical costs, scientists from three Australian universities have discovered.

The research, led by Australian National University (ANU) and conducted in collaboration with Bond University and Sydney University, investigated rates of diagnosis of differentiated thyroid cancer.

Lead researcher Associate Professor Suhail Doi said diagnoses of differentiated thyroid cancer globally had increased three-fold during the past 25 years despite no change to the disease’s low death rate.

“Overly meticulous examinations are detecting the condition in the early stages and resulting in unnecessary surgeries,” said Dr Doi, a clinical epidemiologist at the ANU Research School of Population Health.

“Active monitoring rather than intervention is appropriate in many cases, similar to how doctors treat prostate cancer today,” said Dr Doi, who is also an endocrinologist. He said differentiated thyroid cancer mainly involves papillary and follicular tumours that don’t usually progress to clinical forms of cancer.

Around 2,500 new cases of differentiated thyroid cancer will be diagnosed in Australia this year. In Australia, the diagnosis rate increased by three times for women and two times for men between 1982 and 2012.

In some countries, like South Korea, diagnoses of differentiated thyroid cancer have increased by 15 times in less than 20 years.

Thyroid cancer surgery has substantial consequences for patients. Most patients must receive lifelong thyroid-replacement therapy, and some have complications from the procedure, including damage to nerves and surrounding glands.

Dr Doi said the research findings, published in the Journal of Clinical Oncology, would inform clinical guidelines around the world on appropriate treatment for differentiated thyroid cancer, and also help to educate the public about the condition.

“People with this type of thyroid cancer can sometimes live until normal life expectancy and usually die from other causes, so there is no point intervening if the cancer is acting in a benign way and not causing any problems,” Dr Doi said.

“Only some of these cases require treatment if and when the condition progresses to clinical forms of cancer.”

In 2019, the projected medical care costs for differentiated thyroid cancer in United States is estimated to be more than US$3 billion.

“The medical costs for differentiated thyroid cancer in Australia could be about $US300 million in 2019, if we extrapolate from the US projection,” Dr Doi said.

Dr Doi and his colleagues analysed international autopsy data, including from regions that had high and low instances of differentiated thyroid cancer, over six decades from the 1960s.

They found that incidental differentiated thyroid cancer has remained unchanged, confirming for the first time that the epidemic has been driven by increasing detections of cancer.

“Ultimately, this research will help improve thyroid cancer patients’ quality of life and reduce avoidable burden on health systems.”

ANU PhD student Luis Furuya-Kanamori, Dr Katy Bell from University of Sydney, and Justin Clark and Professor Paul Glasziou at Bond University are the other co-authors of the study.

Country Period Increase
Australia 1982–2012 3 times in women and 2 times in men

Source: Cancer Australia

United States 1975–2013 3 times

Source: US National Cancer Institute

Canada 1986–2015 4.5 times in women and 3 times in men

Source: Canadian Cancer Society

United Kingdom 1979–2013 3 times

Source: Cancer Research UK

South Korea 1993–2011 15 times

Source: Korean Central Cancer Registry