Emerging diagnostic tests for cancer aim to detect the disease in its earliest stages, to improve patients' chances of survival by enabling earlier treatment. Some of these diagnostics — called multi-cancer early detection (MCED) tests — screen for many cancers at once, which sounds great on paper.

However, in February, a flagship trial testing one such cancer test, called Galleri, failed to meet its primary endpoint: it didn't reduce the number of late-stage cancer cases identified. In May, at the American Society of Clinical Oncology (ASCO) meeting in Chicago, attendees got a closer look at some of the data behind the trial.