@lightandhope , the answer to almost everything is, "It depends." 😉

If a tumor starts to grow right after a scan, then you might go 2 full years before another scan, and it could get out of control quickly. But you might also get lucky with timing and catch the tumor on a scan just as it's coming into existence and have almost a 2-year head start on treating it.

Per those MD Anderson guidelines ( https://www.mdanderson.org/content/dam/mdanderson/documents/for-physicians/algorithms/screening/screening-pancreatic-web-algorithm.pdf ), with two or more relatives on the same side of the family having PC, screening would be done every 12 months instead of 24, so that's a benefit.

Screening includes a CA19-9 blood test, which can be done very inexpensively ($25-$50 at some walk-in labs, depending on the state and lab access laws). It's not considered a diagnostic by itself, but a rising trend is reason enough to investigate further. I encourage people at risk to get the test done while healthy, so they'll know their own normal and have a baseline to compare against. It's good to repeat the test a few times (say, once per month for 3 months) so you can see if the data is noisy (all over the place) or pretty consistent. Then spread the tests out further if no significant elevations occur. If rising trends do occur, then get it checked out as quickly as possible by a professional.

Of the many caveats, there are other conditions (serious and benign) that can cause elevated CA19-9, and there are some people with pancreatic cancer who simply don't produce CA19-9. You're always playing the odds, but if you have no symptoms, the odds lean toward the numbers being meaningful.

The cysts can definitely turn cancerous over time, but with guidelines being based on initial scan data, cyst size, and other factors, they have a pretty good set of guidelines for monitoring.

I think my sibling is getting one scan or another every 4 months or so (alternating EUS, CT, MRI, etc) thanks to good insurance and a pretty aggressive, proactive doctor.