Revolutionary Blood Tests Promise Early Cancer Detection for 50 Types

The Promise of Multi-Cancer Detection

A revolutionary new approach to cancer screening is gaining momentum, offering the tantalizing possibility of detecting dozens of cancers with a single blood test. The vision of a single blood test that could screen for dozens of different cancers has tantalized oncologists for more than a decade. The science has advanced at a rapid clip: What began by analyzing levels of proteins in the blood has progressed to scrutinizing tiny amounts of DNA and feeding the data into algorithms that can highlight changes suggestive of cancer.

These multi-cancer early detection (MCED) tests work by checking blood or other body fluid (such as urine or saliva) samples for signs of cancer, such as pieces of DNA, RNA, or proteins from abnormal (cancer) cells. Known as multi-cancer early detection (MCED) tests, they offer the potential to detect up to 50 types of cancer from a single blood draw. The technology represents a significant leap forward, considering that 70% of cancer deaths stem from cancers for which there is no screening test.

Promising Early Results

Recent clinical trials have shown encouraging results that could transform cancer screening. In one study, a blood test called Mercury was able to correctly identify 13 cancers with an average of 87% accuracy, including 77% of stage 1 cancers. The most advanced test, called Galleri, has demonstrated particularly impressive performance in large-scale studies.

Adding Galleri to recommended screening for breast, cervical, colorectal, and lung cancers in PATHFINDER 2 yielded a more than seven-fold increase in the cancer detection rate, and more than half of the Galleri detected new cancers were found in early stages, when cancers are more treatable and potentially even curable. "These results are extremely compelling as approximately three-quarters of the Galleri-detected cancers do not have recommended screening tests today.

The test's ability to pinpoint cancer location is equally impressive. The Galleri test predicts a cancer signal of origin with 93.4% accuracy, guiding an efficient diagnostic work-up. This precision helps doctors know where to look for tumors, potentially speeding up diagnosis and treatment.

Current Limitations and Concerns

Despite the promise, significant challenges remain before these tests become standard care. So far, none of these tests have been approved by the Food and Drug Administration, although Grail has been able to use a regulatory loophole to market and sell the Galleri test without review. But with very few insurers willing to cover it, it's predominantly sold through high-end clinics and medical concierge services to people willing to pay for it out of pocket.

Cost presents another barrier to widespread adoption. The list price for the Galleri test is $949. The annual cost of MCED testing could be about $100 billion a year if all people 50 years of age and older were to be tested this way. Additionally, no studies have assessed the benefit of MCEDs for finding cancer or for improving either the quality or length of a person's life.

The Road Ahead

Medical experts remain cautiously optimistic about the future of multi-cancer blood tests. However, she said, it may ultimately be too optimistic to have a single test which can screen for many dozens of cancers. Instead, she said, the likely future is that there could ultimately be a basket of blood tests which screen for different families of cancers. This approach might prove more practical than the ambitious goal of one test for everything.

MCD tests might be used along with current screening tests, as well as to help find cancers for which there aren't screening tests yet. The technology shows particular promise for detecting aggressive cancers that currently lack screening options, such as pancreatic, ovarian, and liver cancers. As research continues and costs decrease, these innovative blood tests could fundamentally reshape how we approach cancer prevention and early detection.