There have actually been a lot of interesting abstracts this year at ASCO in these multicancer early detection tests. As I’m sure your audience knows, these tests are being done to try and figure out can we do a single blood test that can identify cancers early and how does that compare to what we do with our standard of care screening?

So we had two separate abstracts presented. The first was a study called NHS-Galleri. This was a test using the GRAIL Galleri test in a population and done in collaboration with the NHS. They did three annual tests and then after the baseline tests they randomly assigned people to do the testing versus just bank the test sample. They were looking for a significant decrease in stage III or stage IV cancers combined and they did not meet that. That was their primary endpoint. What they did find was an increase in stage I and stage II cancers over time and a decrease in stage IV cancers over time. They demonstrated a 52% positive predictive value, remember that number. They did show overall an increase in screen-detected cancers and a decrease in clinical presentations or emergency room visits.

The second study was the PATHFINDER 2 study, these results were presented last year at ESMO. We haven’t seen a publication yet. They demonstrated a slightly higher positive predictive value. This, unlike the NHS-Galleri study was not randomised. So people just underwent one baseline test and then, based on the test results, were evaluated for cancer or not. They enrolled 35,000 people, they had 9% of the population with a positive test result and about half of those actually had cancers. A small percentage were recurrent cancers, the majority were new cancers. They found higher rates of positivity in groups who ended up having cancers that we know are more aggressive cancers or represent high mortality or high five-year survival. They did have higher numbers of cancers detected by screening when we look at those overall.

So how do we put these studies in context? What do we do tomorrow? I think nothing different because although multicancer early detection tests are interesting, I don’t think we’ve shown the clinical utility of these. None of these studies have shown that by having these blood tests you can decrease cancer mortality and we know that’s the most important thing. As Dr Robson told us on Sunday and was published a couple of years ago, we know that just decreasing the rate of stage III and stage IV cancers doesn’t necessarily translate into improved mortality. We know that we have lots of cancers, screening tests for cancers, where screening does improve cancer mortality and for things like colon cancer we know that it’s a prevention strategy.

So there are studies being done nationally, the NCI has put a lot of energy, time and money into really trying to do big studies that will determine the clinical utility of these cancers. We need to accrue to those studies and wait for those test results. These tests are expensive, the work-up of cancer for a positive signal is very expensive and the time and anxiety and resources involved in doing those work-ups is not insignificant. If we’re not improving survival, should we be doing it is a question I ask.