@lightandhope , You're very welcome. Two other thoughts/angles I forgot to mention:

1) CEA is another tumor marker similar to CA19-9, but perhaps more applicable (associated with more types of cancer). It is also not a single diagnostic indicator of anything, but as with CA19-9, if you start recording it while healthy, you'll know your normal levels and be better able to recognize if it starts trending above normal. It's a cheap and easy test within the range of self-pay if necessary. For tests like this, it's important to get them done at the same lab for consistency. There can be substantial variation between labs and their tests.

2) There is a "multi-cancer panel" blood test from Grail, called "Galleri." It's supposed to provide early detection of up to 50 different types of cancer. It costs about $1000 and is not FDA approved, so it would definitely be a self-pay. All the usual caveats about sensitivity, specificity, false negatives and false positives (and your response to them) apply. But it is an easily accessible, non-invasive test. Almost any doctor can order it for you, or you can speak with one of Grail's counselors by phone and get it approved.

I was disappointed -- got a false negative from Galleri on my PC recurrence, but that was accompanied by false negatives on Signatera (DNA) test and EUS biopsy as well. MRI and rising CA19-9 were the only reliable indicators of recurrence, although as I've mentioned, I think a PET scan could have confirmed the MRI and CA19-9 results to confirm recurrence of my cancer earlier. PC can be really hard to detect!

In summary, if you're not looking for PC, you might not find it until too late. If you're looking, it improves your overall chances. If you get false negatives, at least you tried your best. But remember that "absence of evidence is not evidence of absence." If you get false positives, it does call for prioritizing further investigation, but not necessarily overreacting. For example, an immediate biopsy after one positive test result might be excessive, invasive, and dangerous. See if the test can be repeated (same and/or different lab) or if a different, non-invasive test can verify the first result before resorting to something surgical or otherwise invasive/dangerous.

And as for the screening guidelines, I read it as you did that screening for your partner would begin at age 50, but that doesn't mean a doctor can't start earlier, which I would definitely do given the family history.

If you can't get doctors/insurers to go along with all the official screening guidelines (i.e., imaging can be expensive), you can still start with PCP or self-referral and self-pay for the basic blood tests. Educate yourself about all the symptoms to watch for and be ready to react quickly if they occur. Adult-onset diabetes, unexplained weight loss, jaundice, changes in stool and urine, digestive issues, and mid-back pain are among many others to be aware of. In my case, the first true red flag was high liver enzymes caused by the tumor blocking my common bile duct. In hindsight, I think my fingernails chipping more than usual might have been an even earlier indicator, suggestive of not properly absorbing nutrition from my food.

Know your body!