90 years ago: TB cannot be cured before penicillin...

90 years ago: TB cannot be cured before penicillin...10 years ago Hepatitis C cannot be cured before Hep C drug. Lot of minor cancers cannot be treated 20 years ago, now can be treated.....

The reason that most advanced cancers cannot be cured because of lack of breakthrough of pathology and medicine.

It takes time for human being to find out ideal therapy for cancers,  even that may happen, new diseases or cancer will come out...