Don,t see why you can't go all on together there's a separate medical screening questionnaire for each traveler.

It pays to shop around as most companies won't even entertain you whilst some take the ***.

After a lot of searching I've found insurancewith to be the most reasonably priced just over half the price of All clear however I still think it's extortion.

Good luck

If you are not all on the same policy, and you (the passenger with the medical condition) cannot travel for any reason relating to your cancer, the other members of your party would not be covered for cancellation by their policy unless they had declared your medical condition on their policy. So it makes sense for you all to be on the same policy, then if one person cannot travel, the others would be covered for cancellation of the whole trip if they didn't want to travel without you. But note that you must read all the small print and check any terms and conditions that are important to you.