You need to be able to trust that your doctors guidance is genuinely what they feel is best based on their training and experience rather than a sponsored treatment they have been paid to prescribe.
I'm colored by just having heard https://www.numberphile.com/podcast/hannah-fry-orchid-cancer which was a podcast episode about cancer treatment and choices - and it says, there's more to it than this. Doctors may not value your life quality as high as you do etc.