Trucheck Intelli vs. Galleri: Which Early Cancer Detection Test Is Right for You?
How can you choose between two such similar options? Read on to understand a little more about the different multi-cancer screening tools.
If you read our update earlier this year on the Galleri cancer screening test from Grail, you might recall our thoughts on the dramatic headlines claiming that the Galleri blood test had 'failed' its recent UK clinical trial. Those headlines were misleading - whilst the trial narrowly missed a complex research goal combining Stage 3 and Stage 4 cancers, it actually cut the most advanced Stage 4 diagnoses by over 20% and caught four times as many cancers overall.
Detecting cancers from simple blood tests has been heralded as the future - but is this true? We firmly believe it is. Identifying cancer early, especially for cancers such as ovarian and pancreatic that lack existing screening programmes, is a major advance.
That is why we are pressing forward with this cutting-edge technology. We are committed to providing our patients with the most advanced tools for managing their health. For some time, we have been proud to offer the Trucheck Intelli test by DATAR as a tool for cancer screening. We are now thrilled to announce that we will soon be adding the highly anticipated Galleri test by GRAIL to our screening options.
Both of these are Multi-Cancer Early Detection tests and work very simply through taking a single sample of blood. In this way, they are designed to identify the earliest signs of cancer in the body before symptoms even appear.
This article is designed to help you to weigh up and compare the tests, so that you can choose the best one for you. The Galleri comes in at a slightly higher price point, but does this mean that it is truly 'better'? Here is everything that you need to know to make an informed decision.
How Trucheck and Galleri Multi-Cancer Detection Tests Work
Although both tests work using a blood test, once the blood samples reach the laboratories, they are analysed quite differently.
Trucheck Intelli: This test works by scanning your blood for Circulating Tumour Cells. These are whole cancer cells that have broken away from a tumour and entered the bloodstream. Trucheck can identify markers associated with over 70 types of solid organ cancers. The test is unable to detect blood cancers such as lymphomas and leukaemias.
Galleri Test: This test looks for cell-free DNA - these are tiny fragments of DNA shed by tumours into the blood. It then examines their 'methylation patterns' (chemical changes that indicate cancer). Galleri focuses on detecting over 50 types of cancer, including certain blood cancers.
Trucheck vs. Galleri: Comparing Cancer Screening Accuracy
To understand this, we need to look at two medical terms: sensitivity (how well the test detects cancer) and specificity (how well the test avoids raising false alarms).
Sensitivity (detecting the cancer)
Galleri: Detects around 40% of all cancers overall, but that increases to 70% for high-fatality cancers such as pancreatic, liver or oesophageal. It looks for fragments of cancer DNA, which can be harder to spot in very early stages.
Trucheck: Reports an 82% to 88% detection rate in clinical studies. It searches for whole tumour cells rather than DNA fragments, though much of its data comes from testing patients who already have cancer rather than large, healthy screening groups. This could explain the statistical gap when comparing the two tests.
Specificity (avoiding false alarms)
Galleri: Has a 99.5% specificity, meaning it very rarely produces a false positive. A lower false-positive rate can be vital for patients who want to avoid any anxiety and unnecessary diagnostic procedures that come with a false alarm.
Trucheck: Scores between 96% to 99% specificity, also keeping false alarm rates very low.
Pinpointing the source of cancer
If a test comes back positive, both tests are exceptional at telling your doctor where to look next. The Galleri test is 92% accurate at predicting the original location of the cancer, whereas the Trucheck is 92% to 96% accurate.
Clinical Evidence and Trials for Trucheck and Galleri
This is one of the main reasons why the Galleri test is so highly praised and commands a slightly higher price. It has a commendable volume of rigorous, large-scale clinical trials backing it which have been published in major oncology journals. These peer-reviewed studies include the CCGA and PATHFINDER studies. Additionally, the test was recently the subject of the NHS SYMPLIFY trial here in the UK. The original trials for Trucheck are undisputed, but they were a few years ago, much smaller and have not had the large follow-up trials to confirm their findings that you might expect to see for such an exciting breakthrough. There is therefore not the evidence that having the test actually reduces your chance of detecting or successfully treating a cancer.
Why Multi-Cancer Tests Don't Replace Standard Screening
Before having one of these tests, there is one crucial caveat that every patient must understand: neither of these blood tests are designed to replace standard national cancer screening programmes, and until large medical studies prove without doubt that they are good enough to do so this will remain the case. It is entirely possible that this evidence will emerge in the coming years. In the meantime you must still attend all of your routine mammograms, cervical smears and bowel screenings. These blood tests are designed to be used in addition to routine screening to give you a wider overview of your potential cancer risk, picking up cancers that we do not currently have routine tests for, particularly those that are often found too late to be cured because of the lack of symptoms at early stages (like pancreatic, ovarian and oesophageal cancers).
Choosing Between Trucheck and Galleri: Which Test Is Best for You?
Due to the difference in how the test samples are analysed, we are not comparing like for like and therefore it is difficult to say one is universally 'better' than the other.
You may choose Trucheck Intelli if you want a highly sensitive test that covers a slightly broader spectrum of solid organ cancers (over 70 types) at a slightly lower price point.
Alternatively, you may opt for the Galleri test if you want peace of mind that this test is backed up by a huge volume of high-profile clinical trials. If avoiding a false positive is your absolute highest priority, Galleri's 99.5% specificity and 93.4% accuracy in pinpointing the exact location of the cancer may make the extra cost well worth it.
Both tests represent incredible leaps forward in preventative medicine. If you would like to discuss which test aligns best with your medical history, family risk factors and budget, please book in a consultation with one of our GPs who would be very happy to take the time to help you make the choice.