As someone who has lost loved ones to Cancer (not Ebola yet but anything can happen) it’s a poor choice of words however like the equally incendiary uses of the word rape it is valid within the English language.
Both may be valid but I don’t think either is appropriate.
I think it’s a cultural thing because both words in their original use are still in parlance in the UK but in the USA I think rape is exclusively associated with sexual rape and cancer is exclusively associated with the disease. I’ve explained that in the UK the words Spastic and Spaz are shockingly offensive. Rape still evokes sexual rape when used in the UK but it’s original meaning “to spoil or contaminate” is still very common. Cancer however is either a disease or a star sign. We would more likely use the more archaic Canker or Cankerous instead of the context of the thread title.