I've got a terminal diagnosis of PCa and had no luck with AllClear. I have tried numerous places including some that had quoted me last year and now are out of play (bust?!). I phoned InsureCancer and they were sympathetic but would only insure a trip at a time, 4-5 weeks out, and following a testimonial from my oncologist. I was more ambitious than this because i want to book my trip(s), including trying to visit my brother in the USA.
The helpful person at InsureCancer suggested i try the government-sponsored site Money Helper
I phoned WorldWide Travel Insurance (they were at the top of the list that day) and got an ANNUAL FAMILY insurance INCLUDING USA! OK not cheap (three figures) but much much more affordable than i had feared, and it cuts out worry and hassle about insurance totally for a whole year... we can go on a booking spree. (Well, if we could afford it of course.) I was so pleased. I even phoned back the next day to double-check. The cover was possible because although the oncologist has said it is terminal she has not (yet) given me a specific 'deadline' to check out. (I also suspect that having had radiotherapy - more or less experimentally in my case with stage 4 PCa - was a good thing, because it is sometimes associated with good outcomes in the insurers' databases - but that is a guess).
Another good thing about WorldWide was that their questions were fairly open and flexible - i had previously found some other companies to follow a rather extensive 'tree' of questions which sometimes did not make a lot of sense. Worldwide did it on the basis of my answers and no contact with oncologist needed.
I am very happy about this, after some disappointing insurance hunting in the past, hence the long email ....
DON'T GIVE UP!! AND GOOD LUCK
sorry for the long post.
(diagnosed Dec 2019, Gleason 4+5, liver, bone, bladder, prostate)