The way Jeff Samoray describes the insurance issue of a cancer treatment might be real in certain countries, but when I was diagnosed with a leukaemia I did not even have time to talk to an insurance company. Within two days I was hospitalised and locked up in a sterile room. If financial aspects would have been an issue I would have worried so much, that I would not even have survived the first week of the treatment.
In Europe and in this case France you have a basic obligatory insurance and a complimentary insurance. The basic insurance, obliged for all regular citizens, pays about 70% of all medical cost and the complimentary insurance pays the remainder. In case you have a "long term or serious and costly" disease you will be covered 100% by the basic insurance. I live some 80 kilometres from the destination hospital that treats my leukaemia problem and I am not able to travel independently to the hospital. In this case a taxi drives me to and from the hospital, all expenses covered by the insurance. No advance payments are needed for medication or treatments either. But, this is the luxury living in the western world and in this case, living in France.