Yes, this is right. But, the even more important metric to measure is mortality. Detecting a cancer that is 100% fatal 1 day earlier than traditional tests obv

Yes, this is right. But, the even more important metric to measure is mortality. Detecting a cancer that is 100% fatal 1 day earlier than traditional tests obviously wouldn't be that impressive. Even if the PPV is very high. It's also very possible that a cancer that is detected accurately 6 months earlier, but that detection still doesn't improve our ability to treat the cancer. In these cases, it might even look like mortality is improved if you measure time from detection to death ("early detection extended survival by 6 months"). But, actually, it didn't change much. So, that's all to say that the "Experimental" in the title should temper expectations considerably, because that has real meaning.