A simple blood sample could, tomorrow, be a game-changer for cancer screening. The Galleri test, developed by American pharmaceutical company Grail, claims to detect more than fifty types of cancer, significantly improving early detection. The results were presented on Saturday, October 18, at the congress of the European Society of Medical Oncology, which was held in Berlin.
A new gem from the Californian biotechnology company, the Galleri test detects DNA fragments in the blood that can indicate the presence of a cancerous tumor. It is based on targeted methylation technology, which identifies cancerous DNA using next-generation sequencing and machine learning. Among the cancers detectable by the Galleri test, some are not currently subject to any systematic screening. In addition to identifying the cancerous signal, the detection process would also be able to identify the origin of the tumor and estimate the stage of the disease, as reported by the American magazine Fast Company.
To obtain these results, a study, called “Pathfinder 2”, was carried out on nearly 35,900 people aged 50 and over, without apparent symptoms. The test identified approximately 40% of cancer cases among participants followed for more than a year. According to Medscape, the leading information site for doctors and health professionals, out of 329 participants ultimately diagnosed, 200 cancers were detected by screening: 133 by the Galleri test and 67 by other methods.
A detection rate multiplied by seven
In other words, the test developed by the American company made it possible to identify more than a third of cancers, 75% of which usually escape traditional screening. Combined with existing tests for breast, cervical, colon, lung and prostate cancers, the Galleri test “made it possible to increase the cancer detection rate by more than seven”specifies Josh Ofman, president of Grail, in a press release. The test would also be able to detect notoriously silent tumors, such as those of the ovary or pancreas.
Still according to Grail, more than half of the cancers detected were at an early stage (stage I or II) and their origin could be determined in 92% of cases. Promising figures, which the company does not hesitate to present as an advance likely to save lives. “The vast majority of people die from cancer because the disease is detected too late”recalls Harpal Kumar, president of the biopharmaceutical division, interviewed by the BBC.
But before imagining this test in all laboratories, researchers call for caution. The results must be confirmed by other studies and this is already the case: Galleri is currently being tested in England on 140,000 patients of the British public health system (NHS). Results are expected in 2026.
