Anyone with advice on travel insurance when you have cancer?

I finished treament in October of '17, and we booked a cruise in January of '18 to be taken in August of '18.  I had never purchased travel insurance before, but I did for this trip in case I recurred before we could go, since I was booking so far out.  Well, I didn't recur, but I DID fall down the steps on the cruise ship on the very first day, breaking tibia, fibula and talus (unstable trimalleolar fracture) which earned me a fastpass home for surgery.  What I didn't know was that our health insurance was no good on international waters, so the trip insurance paid my $2,000 medical bill on board and reimbursed us for most of the lost cruise.  I'll never be without trip insurance again.  We used Allianz.

We have Medicare.   We bought a HMO policy on top of Medicare.   That policy covered travel outside the US, and also outside our State.  It was bought out by a company that didn't cover my oncologist so we bought Kaiser PPO.   But then I discovered my gyne oncologist was not in their network.  My cousin is a medical social worker, and she told me she had purchased a supplemental plan because she wanted to see any doctor she chose.  I did not understand the difference between the two types,  supplemental and medicare advantage plans.  So we bought a supplemental plan.  And now I find out they don't cover travel.  I will be buying medical travel insurance because we travel to Canada a lot, and foreign travel once a year.  We used a broker, and she said we could come in and buy our travel insurance from several plans they sell.  I know you don't have Medicare but the health care bokers also sell this type.  She said they are very different.  And buying for the whole eyar is a better deal than buying per trip.  Just general information.