Thyroid cancer 'epidemic' due to overdiagnosis

accreditation
iStock

A reported epidemic of thyroid cancer in rich countries is in fact mainly due to overdiagnosis driven by new technologies, the UN's cancer research agency said.

Arrival of ultrasound

Up to 90 percent of the thyroid cancer cases diagnosed in recent decades are, instead, tumours that are "very unlikely" to cause any symptoms at all, let alone death, according to findings published in The New England Journal of Medicine.

Experts from the International Agency for Research on Cancer (IARC) and Italy's Aviano National Cancer Institute combed through data collected by the UN agency from 12 high-income countries – eight in Europe, along with the United States, Japan, South Korea and Australia.

Starting in the 1980s, the highest rates of overdiagnosis occurred in the US, Italy and France, they found.

Read: Advanced image scans spotting more thyroid cancer

The jump in reported cases of thyroid cancer coincided with the arrival of ultrasound as a diagnostic tool, they noted.

"The most recent and striking example is the Republic of Korea," said IARC scientist Salvatore Vaccarella, who led the study.

"A few years after ultrasonography of the thyroid glands started being widely offered..., thyroid cancer has become the most commonly diagnosed cancer."

The researchers estimate that 90 percent of cases in South Korea from 2003 to 2007 were due to overdiagnosis.

During the same period, 70 to 80 percent of cases in Australia, France, Italy and the US can be attributed to overdiagnosing, and 50 percent of cases in Japan, the Nordic countries, England and Scotland.

The more recent introduction of computed tomography (CAT scans) and magnetic resonance imaging (MRI) have also led to the detection of many non-lethal anomalies in the thyroid glands of healthy people of all ages, the study said.

More monitoring, less surgery

Thyroid cancer – which strikes women far more than men – attacks the butterfly-shaped gland in the neck that produces hormones regulating how the body uses energy.

Patients diagnosed with the disease typically undergo partial or total removal of the gland, which can trigger chronic pain and requires hormone treatment for life.

In total, nearly half-a-million women and 90,000 men in the 12 countries examined may have been told they had the cancer when, in fact, their lives were not threatened, the study concludes.

The authors caution against systematic screening of the thyroid gland, and suggest "careful monitoring" instead of surgery for patients affected by low-risk tumours.

Read: Not all thyroid cancers need treatment: study

"The drastic increase in overdiagnosis and overtreatment of thyroid cancer is already a serious public health concern in many high-income countries," IARC director Christopher Wild said.

There are "worrying signs" of the same trend in low- and middle-income nations, he added.

Experts not involved in the study backed its conclusions.

"Finding cancers that would never cause someone harm in their lifetime – 'overdiagnosis' – is increasingly being recognised as a problem in thyroid cancer around the world," said Jana Witt, Cancer Research UK's health information officer.

"It's likely to be at least partly caused by advances in diagnostic and screening tests making it easier to find cancers that don't need treating and would not be life-threatening."

Witt speculated that the larger rise in women being diagnosed with the disease could be because they are more likely to be offered thyroid examinations as part of regular check ups.

Read more:

Symptoms of cancer

Treating cancer

Preventing cancer

We live in a world where facts and fiction get blurred
In times of uncertainty you need journalism you can trust. For 14 free days, you can have access to a world of in-depth analyses, investigative journalism, top opinions and a range of features. Journalism strengthens democracy. Invest in the future today. Thereafter you will be billed R75 per month. You can cancel anytime and if you cancel within 14 days you won't be billed. 
Subscribe to News24
Voting Booth
Zama zama crackdown: What are your thoughts on West Village residents taking the law into their own hands?
Please select an option Oops! Something went wrong, please try again later.
Results
Authorities should bring in the army already
10% - 1291 votes
Illegal miners can't be scapegoated for all crime
51% - 6425 votes
What else did we expect without no proper policing
35% - 4479 votes
Vigilante groups are also part of the problem
3% - 433 votes
Vote
Rand - Dollar
16.24
-0.2%
Rand - Pound
19.82
-0.1%
Rand - Euro
16.78
-0.5%
Rand - Aus dollar
11.54
-0.5%
Rand - Yen
0.12
-0.1%
Gold
1,789.14
-0.2%
Silver
20.31
-1.4%
Palladium
2,289.00
+1.5%
Platinum
960.50
+1.5%
Brent Crude
97.40
+1.1%
Top 40
64,617
+2.3%
All Share
71,265
+2.1%
Resource 10
65,851
+2.1%
Industrial 25
87,063
+2.8%
Financial 15
15,964
+1.3%
All JSE data delayed by at least 15 minutes Iress logo
Editorial feedback and complaints

Contact the public editor with feedback for our journalists, complaints, queries or suggestions about articles on News24.

LEARN MORE