New blood test set to detect cancer before symptoms appear

Wednesday January 31 2018

An illustration showing a cancer cell. Cancer

An illustration showing a cancer cell. Cancer patients who depend on Mercaptopurine will have to either do without it, or resort to other drugs. FILE PHOTO | NATION 

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Scientists at Johns Hopkins University in the US have developed a simple non-invasive blood test that can detect signs of eight types of cancer long before any symptoms of the disease arise.

The universal blood test for cancer offers hope for a reduction in cancer deaths as it would lead to early detection and treatment.

The test is described in a paper published in the journal Science, where authors said the new work represents the first non-invasive blood test that can screen for a range of cancers all at once: Cancer of the ovary, liver, stomach, pancreas, oesophagus, colon, lung and breast.

“The goal is to look for as many cancer types as possible in one test, and to identify cancer as early as possible,” said Nickolas Papadopoulos, a professor of oncology and pathology at Johns Hopkins, who led the work.

“We know from the data that when you find cancer early, it is easier to kill it by surgery or chemotherapy.”

The CancerSEEK test

Known as the CancerSEEK test, the universal test looks for mutations in 16 genes that regularly arise in cancer and eight proteins that are often released. It can also help locate the disease in the body.

CancerSEEK builds on 30 years of research. The test could also identify the form of cancer that a patient has, something which previous cancer blood tests have failed to achieve.

The new test works by detecting free-floating mutated DNA, released into the bloodstream by dying cancer cells.
Tumours release tiny traces of their mutated DNA and proteins they make into the bloodstream.


“The use of a combination of selected biomarkers for early detection has the potential to change the way we screen for cancer, and it is based on the same rationale for using combinations of drugs to treat cancers,” said Prof Papadopoulos.

A trial was done on 1,005 patients with cancers in the ovary, liver, stomach, pancreas, oesophagus, colon, lung or breast that had not yet spread to other tissues. The test successfully detected cancers 70 per cent of the time across eight of the most common cancers.

The ability of the test to spot the disease varied from one type of cancer to another and was as high as 98 per cent for ovarian cancer and as low as 33 per cent for breast cancer.

For the five cancers that currently have no screening tests — ovarian, liver, stomach, pancreatic and oesophageal cancers — sensitivity ranged from 69 per cent to 98 per cent.

Test’s effectiveness

Although some experts said it was “enormously exciting,” others said more work was needed to assess the test’s effectiveness at detecting early-stage cancers. First, 80 per cent of the cancers evaluated were stage two or stage three – fairly advanced.

CancerSEEK is not yet available to the public, and it probably won’t be for a year or longer, Prof Papadopoulos said.

“We are still evaluating the test, and it has not been commercialised yet,” he said. “I do not want to guess when it will be available, but I hope it is soon.”

According to Dr Julius Onyango, a Kenyan oncologist, this is welcome news since most cancer cases in the country are diagnosed late.

“These diagnostic advancements hold immense promise to reduce Kenya’s cancer mortality because the earlier it is detected, the higher the chances of survival,” he said.


The Economic Survey 2017 showed that more than 27,000 deaths are recorded in the country per year. Sixty per cent of Kenyans affected by cancer are below the age of 70.

The leading cancer in women is breast cancer with over 34 per 100,000 deaths, followed by cervical with 25 per 100,000. In men, the prostate leads with 17 per 100,000 followed by oesophageal with nine per 100,000.

The high cost of treatment, lack of awareness and widespread poverty have led to diagnosis in more than 70 per cent of the cases.

Additional reporting by Angela Oketch.