> In the case of pancreatic cancer, it is much more aggressive and you need to catch it early.
It's not clear that the cancers that you would find early with a more sensitive test are those more aggressive cancers.
The pancreatic cancers we find with our current detection (generally after becoming symptomatic) are typically quite aggressive. But are they all the cancers? Likewise, if the cancer is aggressive, it can grow quite a bit between screening intervals and not be found all that early.
(Part of why we think that "finding cancer early" is such a benefit is that because the smaller/earlier cancers we find are less aggressive than the cancers that we first find when they're huge and spread. There is definitely an effect from earlier detection but our estimate of it has been confused by this effect.)
As we've increased cancer screening, we've found that survival rates have gone up, as have survival times after detection... but unfortunately we've often also found that the screening doesn't always reduce the number of people dying of that cancer at a certain age. Instead, you find more cancers, and you find them earlier so more people live to 5 years, even if you've changed nothing. Cancer treatment has gotten better, but most of the benefits we have expected from better cancer screening have not materialized.
Finding pancreatic cancer early sounds good. And it may be able to reduce mortality from pancreatic cancer, but it's not a sure thing.
It's not clear that the cancers that you would find early with a more sensitive test are those more aggressive cancers.
The pancreatic cancers we find with our current detection (generally after becoming symptomatic) are typically quite aggressive. But are they all the cancers? Likewise, if the cancer is aggressive, it can grow quite a bit between screening intervals and not be found all that early.
(Part of why we think that "finding cancer early" is such a benefit is that because the smaller/earlier cancers we find are less aggressive than the cancers that we first find when they're huge and spread. There is definitely an effect from earlier detection but our estimate of it has been confused by this effect.)
As we've increased cancer screening, we've found that survival rates have gone up, as have survival times after detection... but unfortunately we've often also found that the screening doesn't always reduce the number of people dying of that cancer at a certain age. Instead, you find more cancers, and you find them earlier so more people live to 5 years, even if you've changed nothing. Cancer treatment has gotten better, but most of the benefits we have expected from better cancer screening have not materialized.
Finding pancreatic cancer early sounds good. And it may be able to reduce mortality from pancreatic cancer, but it's not a sure thing.