Cancer Blood Test Hype Faces Serious Questions

The Galleri test, developed by Biotech giant Grail, claims it can detect over 50 types of cancer at early stages through a simple blood draw. Through the examination of minute pieces of DNA released by tumours, AI is capable of identifying cancers, such as pancreatic cancer, that normally cannot be detected until advanced stages. Early diagnosis in this case can be life-saving, and that is where the Galleri test comes in (1^✔ ✔Trusted Source
Multi-cancer Early Detection (MCED) Tests

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What Experts Are Worried About?

However, despite its initial promise, an extended study in the UK was abruptly terminated after the first year, supposedly because of disappointing outcomes. Since the information has not been made public, there are concerns regarding whether the test is prepared for widespread usage. There are even specialists who compare the fuss to the Theranos scandal, in which big claims were made before sound research was done. Once hailed as a $9 billion startup, it ended in fraud convictions and a cautionary tale for Silicon Valley.

Researchers and doctors are doubting whether the test actually lives up to its commitments. Key concerns include:

• False alarms: How many results are wrong, leading patients to stressful and invasive follow-up tests?
• Missed cancers: How many patients later developed cancer despite testing negative?
• High cost: At about $1,000 per test, what happens if results are unclear—do patients get refunds?
• Accuracy issues: Does the test accurately detect the kind and location of cancer, or does it occasionally lead medical professionals in the incorrect direction?

What is Multi-Cancer Early Detection Tests?

Galleri is one of a new category of tests known as multi-cancer early detection (MCED) tests. Blood is often drawn for these tests in order to look for cancerous traces, which are bits of DNA, RNA, or proteins that sick cells have shed. Some can even tell where in the body the cancer might have originated. Notably, the tests do not diagnose cancer; a positive test would relate to further follow-up testing to ascertain the existence of cancer.

The reason why MCED tests are being developed is that only a few cancers, including breast, cervical, colorectal, lung, and prostate, have a proven screening method. In most cancers, there is no routine screening, and hence most are diagnosed only at more advanced and difficult-to-treat stages. Although it is believed that tests like MCED would be able to detect a wide range of cancers much earlier, the FDA has not yet authorized any of them, and research is being done to determine whether or not they actually save lives (2^✔ ✔Trusted Source
Implosion of Grail's Galleri Cancer Screening Test?

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The Bigger Picture

The biggest question is still unanswered: Does the Galleri test truly save lives by detecting cancers early and improving survival? Experts stress that Grail must be fully transparent with its current data until the long-term results, expected in 2026, are available. Regulators may also need to step in to protect both patients and investors from overly optimistic claims.

While the Galleri test could one day prove to be a breakthrough in cancer screening, it remains unproven. For now, patients should understand that both the potential benefits and the risks are uncertain — and think carefully before spending thousands of dollars on a test that might not yet provide the peace of mind it promises.

Reference:

1. Multi-cancer Early Detection (MCED) Tests - (https://www.cancer.org/cancer/screening/multi-cancer-early-detection-tests.html)
2. Implosion of Grail’s Galleri Cancer Screening Test? - (https://pmc.ncbi.nlm.nih.gov/articles/PMC11886625/)

Source- American Cancer Society