A SIMPLE BLOOD TEST, instead of a painful biopsy, could give us mastery over cancer by detecting nearly every case before it spreads, scientists say. The technology – which can identify 70 types of cancer – is now being used in a few countries abroad.
Scientists believe such techniques could be introduced as standard screening within the next five to ten years, allowing oncologists to eradicate cancer long before symptoms are present.
Research on 30,000 people found the checks could identify 91.8 per cent of cases which were non-metastatic. This meant it was more treatable, because it had not spread beyond the primary site where it was found.
The NHS is already running the largest ever trial of blood tests to screen for cancer, involving 140,000 people, with hopes it could prevent one in ten cancer deaths. So far, studies have found that the Galleri test, which can detect at least 50 types of cancer, is able to detect more than half of cases of the disease.
But another company believes that a different type of “liquid biopsy,” called Trucheck, could prove still superior – especially at detecting cases at the earliest stages, when they are most treatable.
The tests were able to detect nine in 10 cases of cancer whether or not it was metastatic. By contrast, the Galleri test reached similar levels of performance when cancer had reached stage four, meaning disease was advanced and may be terminal.
The blood test itself takes less than a minute, involving just two 10-ml vials. The system of liquid biopsies works by detecting circulating tumor cells which are released by malignant growths but not from non-cancerous tissue.
Over a five-day process in the lab, healthy cells are stimulated to die. Cancer cells are resistant, meaning those that remain will grow, and form clusters.
If these are identified, patients undergo an in-depth consultation, after which they can be booked in for further checks, and continue private treatment, or take the information back to their doctor.
Studies of Galleri, a test developed by the company GRAIL, have found that at stage 1 it was able to detect 16.8 per cent of cases, rising to 40.4 per cent at stage 2, 77 per cent at stage 3 and 90.1 per cent at stage four.
By contrast, the test called Trucheck, was able to spot 91.8 per cent of cases which were non-metastatic. It also found 92.6 per cent of cases where disease had spread beyond the primary site.
Even at stage three, cancer can remain “non-metastatic” and the study of Trucheck did not show how many cases were picked up at this stage, rather than at stages one or two, when it is most amenable to treatment.
However, separate studies on breast cancer found the new technology was able to identify almost nine in 10 cases at stage one, while Galleri picked up around 16 per cent of cases. The findings are not enough as the test’s ability to detect early-stage cancers appears limited, and they don’t show how good the test is at picking up cancer in a population where individuals may or may not have cancer. Further research is needed to answer these questions. By Manny Palomar, PhD (EV Mail May 15-21, 2023 issue)
