Friday, 23 February, 2018

New blood test detects eight common cancers

A robot processes patient blood samples for evaluation with the CancerSEEK test. Fred Dubs Johns Hopkins Medical Pathology A robot processes patient blood samples for evaluation with the CancerSEEK test. Fred Dubs Johns Hopkins Medical Pathology
Theresa Hayes | 21 January, 2018, 02:08

Developed by researchers from John Hopkins University in the USA the new test is called CancerSEEK.

"The clever part is to couple DNA with proteins", says cancer researcher Alberto Bardelli of the University of Turin in Italy, who was not involved in the work.

In a statement, Australian scientist Professor Peter Gibbs, who contributed to the research, said the test was urgently needed because cancer mortality rates are directly related to how advanced a cancer is at diagnosis. While there is still a great deal of uncertainty, this is the first step in a long journey - and the first step is always the hardest. However, this can prove hard as a lot of the tests that are now in use may not be sufficiently accurate, or the symptoms may only be detected at a late stage.

How accurate was the test? And the test isn't as good as it could be for the earliest possible stages of cancer, Roschewski noted. However, this is not a test that will detect every cancer, every time.

He said: "A novelty of our classification method is that it combines the probability of observing various DNA mutations together with the levels of several proteins in order to make the final call".

With 134,174 new cancer cases previous year diagnosed in Australia, the new blood test would screen for key proteins and gene mutations that indicate cancer. "This is the paper that's going to set the field in motion".

Working with blood samples of 1,005 people with one of the eight different cancer types, researchers used CancerSEEK to reliably identify the tumors in 70 percent cases. Only seven were flagged as positives, meaning researchers could not be certain if the results were false positives or the seven individuals had early-stage cancer but were showing no symptoms. "That could save their life", said study author Nickolas Papadopoulos in an interview with NPR. Certain cancers seem to be easier to detect than others. The most common stage at presentation was stage 2 (49%); 20% of patients had stage 1 disease; and 31% had stage 3 disease. So patients in a real-life screening likely would have less advanced disease and might be more hard to test.

Another concern is whether the false-positive rate might be higher in the general population, says Catherine Alix-Panabières, a cancer researcher at the University of Montpellier in France.

The researchers added that the results "lay the conceptual and practical foundation for a single, multi-analyte blood test for cancers of many types". "The sensitivity for the stage I cancers in the study was only 40%".

Many groups in academia and industry have focused on using liquid biopsies to track cancer progression and to guide physicians as they formulate a treatment plan.

"Scientists have devised a single blood test that screens for eight common cancer types and helps identify the location of the cancer". Is that good enough for screening large numbers of people?

And according to the ACS web site, "prostate cancer can often be found early using a simple blood test, but it's not clear if the benefits of testing all men for prostate cancer outweigh the risks, such as finding (and treating) cancers that probably never would have caused any problems".