Even if you don't accept that the extrapolations and assumptions abou the impact of advances is not valaid (and that in itself would be silly), your statement the wide majority (of cancers) kills you rather quickly, therapy or not, really is ridiculous. 

 I've quoted data for Australia.  The survival rates in other Western and advanced Asian countries won't be much different - I can assure you there's nothing special about Australian doctors and hospitals.  I don't know what country you are in.  Statistically, as a wikipedian you are likey to be American.  Data for USA may be dragged a little worse because USA has a larger and more diverse fraction of minorities in the population.  It seems to be a fact of life that minorities the World over take less care of their health, and don't get as good medical care as the main population.  On the other hand USA has some superb hospitals and specialist doctors of a higher calibre than we have in Australia.