The Galleri® Multi-Cancer Early Detection Test in Leicester

Offered by The Health Suite in partnership with Preologi, the first organisation in the UK authorised to provide the Galleri® test — working with GRAIL.

Why it matters: the screening gap patients face today

In the UK, only four cancers have a recommended national screening test — breast, cervical, bowel and lung. Together, these programmes detect only a small fraction of all cancers, which means most are still found only once symptoms appear, often at a later and harder-to-treat stage.

• 4 cancers have a recommended UK screening test today (breast, cervical, bowel, lung).
• 5–6% of all cancers are currently detected through those screening programmes.
• ~45% of UK cancers are diagnosed at stage 3 or 4, when treatment is far less effective.
• Below 20% five-year survival for many late-stage cancers, versus over 90% for several cancers caught at stage 1.

What it is: one blood draw, a signal common to over 50 cancers

Galleri is a multi-cancer early detection (MCED) test developed by GRAIL. Rather than looking for one cancer at a time, it examines cell-free DNA (cfDNA) shed into the bloodstream — including by cancer cells — and reads its methylation patterns, the chemical marks that are distinctive to cancer. From a single sample, it looks for a signal shared by more than 50 cancer types and, where a signal is found, predicts the likely tissue of origin to help direct the next investigation.

Its particular value is that most of these cancers have no recommended screening programme in the UK at all. Galleri is designed to complement — not replace — established programmes such as breast, cervical and bowel screening.

How the test works — the science

1. Blood draw — a single sample is taken at the clinic. No fasting or special preparation.
2. cfDNA extraction — cell-free DNA shed by cells is isolated from the sample.
3. Methylation sequencing — the laboratory reads the cancer-specific methylation marks.
4. Signal classification — machine learning determines whether a cancer signal is present.
5. Signal origin — where present, the likely tissue of origin is predicted.

Galleri® is a screening aid, not a diagnostic test. A positive result needs diagnostic confirmation; a negative result does not rule out cancer.

What the studies show

Galleri is supported by an unusually large evidence base for a screening test: the PATHFINDER and PATHFINDER 2 studies (around 42,500 participants) and the NHS-Galleri trial — the world’s largest MCED study, with more than 140,000 participants.

• 99.6% specificity — fewer than 1 in 200 results are false positives.
• 40.4% overall sensitivity across all cancers (73.7% for the 12 deadliest cancers).
• ~93% accuracy in predicting the cancer’s tissue of origin.
• 60.3% positive predictive value — around 6 in 10 positive results are confirmed as cancer.

Sensitivity — the proportion of cancers the test detects — rises steeply with stage, because more aggressive and advanced cancers shed more DNA into the blood:

PATHFINDER 2 — around 30,000 participants, one Galleri test, 12-month follow-up. 54% of cancers detected were stage I or II, and adding Galleri to recommended screening produced a roughly seven-fold increase in screen-detected cancers within a year.

NHS-Galleri trial — more than 140,000 participants aged 50–77, three annual tests. The trial found a stage shift towards earlier diagnosis, roughly four times more cancers found through screening, and fewer emergency (A&E) presentations. It did not meet its primary endpoint of a statistically significant fall in late-stage disease, and long-term survival data is still maturing.

Sensitivity varies considerably by cancer type; it is highest for the higher-mortality cancers that shed more DNA earlier. No MCED test has yet published evidence that screening reduces cancer mortality.

The Galleri® test screens for a signal across 50+ cancers

These include many cancers with no existing NHS screening programme. A selection of the cancer types:

• Chest & airway: lung, head & neck, oesophageal.
• Digestive: colon & rectum, pancreatic, stomach, liver & bile duct, gallbladder, anus.
• Women’s health: breast, ovarian, cervix, uterine.
• Blood & other: lymphoma, leukaemia, plasma cell myeloma, melanoma, bladder & urinary tract — and more than 50 in total.

Who it’s for

Galleri is intended as an addition to standard screening for adults at higher risk of cancer — typically those aged 50 and over. It is most valuable for people who want to look for cancers that have no routine screening test.

• Adults aged 50 and over, or younger adults with an elevated personal or family risk.
• People already up to date with their standard NHS screening.
• Those wanting broader reassurance beyond single-cancer tests.

Important information — intended use & limitations

• Intended for adults with an elevated risk of cancer, such as those aged 50 or older. It is not recommended during pregnancy, for those aged 21 or under, or for anyone in active cancer treatment.
• It does not detect all cancers and must be used in addition to — not instead of — routine screening.
• A positive result requires diagnostic confirmation through further clinical investigation; it is not a diagnosis.
• A negative result does not rule out cancer or replace ongoing screening. Continue to act on any new or persistent symptoms.
• No MCED test, including Galleri, has yet published evidence that screening reduces cancer mortality; this is the subject of ongoing trials including NHS-Galleri.