But does the test mean fewer cancers are found at a late stage?

Transcript

1. This is a tube of blood.
2. A company called GRAIL says its test can detect more than 50 types of cancer in it,
3. before you feel ill.
4. It already sells in America for $949.
5. This week, advisers to the US FDA voted on it.
6. But does the test mean fewer cancers are found at a late stage?
7. In England, 142,000 people aged 50 and over joined a trial.
8. Each was put, at random, into one of two groups.
9. One group had its blood tested, with an earlier version of the test.
10. The other group's blood went into a freezer, untested.
11. Both kept their usual care, so cancer could still be found in either.
12. They gave blood up to three times, a year apart.
13. If testing helps, the tested group should see fewer late diagnoses.
14. Doctors call stages three and four late.
15. By stage four, cancer has usually spread to other organs.
16. In the first year, the test flagged 419 cancers.
17. Another 708 people were diagnosed with cancer within a year of a negative test.
18. Nobody can say how many of those cancers were already there.
19. Now count late cancers of 12 deadly types in each group.
20. In year one, the tested group had more.
21. In years two and three, fewer.
22. Each gap could be down to chance.
23. Over all three years, the two groups came out almost level.
24. The trial missed its goal.
25. Another planned result: the tested group had 14% fewer stage four cancers,
26. at the edge of chance.
27. But more stage threes.
28. GRAIL says some of those were caught before stage four.
29. Richard Houlston, a London cancer researcher who declared no conflicts,
30. calls that explanation entirely speculative.
31. GRAIL is not asking to sell it as cutting stage four cancers,
32. and the advisers were not asked about that.
33. They reviewed a newer version than the trial used.
34. Asked if its benefits outweigh its risks,
35. seven of the ten said yes, two said no, and one abstained.
36. Some doubted it finds cancer early.
37. The FDA has not decided yet.
38. Late cancers were counted because deaths take more people and years to measure.
39. Cancer deaths in each group are not yet published.
40. The designers wrote the trial would be too small to compare them directly.