My mum was an Oncology nurse for a little bit.  I was leaning towards that area myself, because my father has Leukemia.  She said it was very hard.  I think you have to be a very strong person to deal with those with Cancer, the chemo treatments, the aftermath.  But at the same time I think it would be rewarding, seeing those who have fought and over come.  I think the best answer is to maybe visit an Oncology office....or prehaps a unit.