I have zero medical training, but if you were diagnosed 5 years ago, my math says you've already "waited."

What I hear a lot about cancer "progressing" on one treatment and becoming time to try something else is if a _tumor_ has increased in size by 20% or more in its largest dimension. Your _cyst_ (from 3.2 cm to 4.1) looks like a 28% increase to me.

I've seen protocols and criteria for monitoring IPMN cysts, but really no nothing about MEN1.

At a minimum, I would recommend erring on the side of caution -- find a pancreatic center of excellence and get a "tie-breaker" third opinion as soon as possible, and ask them to do all the relevant genetic, blood, imaging, and other tests possible to support their recommendation.

If nothing else, you'll have a better idea what's going on, possible get management that prevents other complications, and have yourself an "in" at the center of excellence in case you need them in a hurry later on.