Cancer

Updated 15 August 2017

Rare sinus cancer can now be found via blood test

Although sinus cancer is extremely rare, and mostly common in parts of Asia, the test offers possibilities for other cancers.

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Sinusitis is a common condition many people suffer from, but sinus cancer is something else to be concerned about. Luckily, this cancer is extremely rare.

A new DNA blood test can catch a rare but deadly form of cancer that occurs in the sinuses, researchers report.

An accurate test

The test, which looks for DNA evidence of Epstein-Barr virus in blood samples, was 97% accurate at detecting the presence of nasopharyngeal cancer, according to the results of a clinical trial.

"I believe that the test is technologically ready for use for screening nasopharyngeal cancer in high-risk areas like Hong Kong," said senior researcher Dennis Lo. He's an associate dean of research and director of the Li Ka Shing Institute of Health Sciences with the Chinese University of Hong Kong.

sinus cancer

What is 'sinus' cancer?

The nasopharynx is the upper part of the throat that lies behind the nose, just above the soft part of the roof of the mouth and just behind the nasal passages, according to the American Cancer Society (ACS). It serves as a passageway for air between the nose and the throat. This is where nasopharyngeal ("sinus") cancer appears.

Nasopharyngeal cancer is relatively rare, with less than one case for every 100 000 people in the United States and many other parts of the world, the American Cancer Society (ACS) says. The prevalence is also extremely rare in South Africa, with a 0.2% chance of mortality in 100 000 people.

However, it is much more common in southern China and other parts of Asia and North Africa, making a test for early detection an important way to potentially save lives there, according to the ACS. 

Cancer linked to Epstein-Barr virus

Nasopharyngeal cancer is closely related to the Epstein-Barr virus, a member of the herpes family, Lo explained. "The Epstein-Barr virus genome can be found in more than 99% of tumour cells of nasopharyngeal cancer," Lo said. "It is believed that the virus is one of the causative factors for this cancer."

Based on this, Lo and his team developed a test to detect fragments of Epstein-Barr virus contained in tumour DNA that's released into the bloodstream as cancer cells die in a patient's body.The DNA test wound up accurately detecting nasopharyngeal cancer 97% of the time. It accurately ruled out healthy people 98% of the time, study results showed. The study was published in the Aug. 10 issue of the New England Journal of Medicine.

Dr. Richard Ambinder is a professor of oncology with the Johns Hopkins School of Medicine in Baltimore. He said, "By surveying the blood and looking for the fragments of the viral DNA, you could pick out people who needed a more careful look to see if they had an early cancer, and very often they found that they did."

Test of great value in high-risk countries

Ambinder said the test will be of greatest value in Asian countries, and likely will not be pursued in the United States.

"We don't have the same incidence of nasopharyngeal cancer that Hong Kong and southern China have, so I don't have any idea whether someone is pushing for approval here," Ambinder said. "I don't think it's going to be high on anyone's priority list as a screen."

New methods for other cancers

But this new report does point to new ways in which other virus-related cancers can be identified early, said Ambinder, who wrote an editorial accompanying the study.

"What's leaking out from the tumour cells here is tumour DNA that includes with it viral DNA," Ambinder said. "There's a lot of interest and progress made in diagnosing other tumours by the presence of tumour DNA in blood. There are some things about finding the viral DNA that make it a little easier to find," he added.

"I expect that there are a lot of cancers that we're going to be able to diagnose by the presence of these fragments of DNA," Ambinder continued. "This is only the beginning, but it wouldn't surprise me at all if this applied to many common cancers.

Image supplied by iStock

 

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CANSA’s purpose is to lead the fight against cancer in South Africa. Its mission is to be the preferred non-profit organisation that enables research, educates the public and provides support to all people affected by cancer. Questions are answered by CANSA’s Head of Health Professor Michael Herbst. For more information, visit cansa.org.za.

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