This is a good one. Cancer is one of the diseases that has really threatened mankind and so stubborn to any treatment and very fast on the victims. One way I think blockchain technology can be utilized in via data sharing. In almost all our hospitals or clinic data transfer even between two nearby desk takes so much time and some times leads to unwanted delay that ends badly with the patients. If blockchain can be used to hasten data transfer while protecting it privacy I will a long way in helping the not only the patients but the entire healthcare sector. Honesty with blockchain technology there is limitless possibilities.
It's useful to actually correctly understand the "medical privacy problem."
Medical privacy rules are covered in the USA by HIPAA rules. These make sharing data extremely simple for some, and extremely difficult for others.
Extremely simple - Government agency -- other agencies, law enforcement at all levels
Extremely hard - you to give / show your data to other individuals
You see? Blockchain is being actually proposed here as a way around stupid government regulations.