Regularly checking people that are otherwise healthy for cancer will turn up a lot of cancer through false positives or slowly growing ones, will lead to a lot of unnecessary intervention and will in fact lead to a reduction in quality of life and lifespan. This is one of the reasons why exhaustive cancer screening (which was more costly in the past but could have been done) was not promoted, it had nothing to do with ability, but everything to do with outcomes.
Those cancers where checkups are useful we already do regular screenings for.
For aggressive cancers - the ones that are really problematic - you would have to do such a test too frequently to make any real difference, for instance, if you were to test annually you'd be on average 6 months away from your next test, plenty of time for such a cancer to develop and kill you.
So this is not the kind of breakthrough that you may think it is.
Those cancers where checkups are useful we already do regular screenings for.
For aggressive cancers - the ones that are really problematic - you would have to do such a test too frequently to make any real difference, for instance, if you were to test annually you'd be on average 6 months away from your next test, plenty of time for such a cancer to develop and kill you.
So this is not the kind of breakthrough that you may think it is.