Have an Answer?
If you want to become an oncologist who treats cancer, then this involves becoming a physician. Most people first get a 4 year college degree, then enter medical school. Medical school is 4 years long. After this, your do a 3 year residency in internal medicine or pediatrics. If you want to treat adults, you will need to do a 3 year residency in internal medicine. If you want to treat children, you will need to do a 3 year residency in pediatrics. After your 3 year residency, the next step is 3 year fellowship in oncology. There is also a field called radiation oncology. After 4 years of medical school, you do about 4 or 5 years of residency in radiation oncology. Radiation oncologist only provide radiation therapy to patients, and do not provide any other treatment besides radiation.
If you are interested in researching cancer rather than treating it, then you can do any of the above training, then enter into research in oncology, perhaps at a major research university. Or, you can get a 4 year college degree, perhaps in biology, then follow up with an advanced college degree in something related to cancer. In order to get a PhD, which you can use to further your research career, you will need to study about 5 years in a graduate degree program after your four year college degree. It would be helpful to attend a major research university for these degrees to help getting into research.
I hope this is helpful.