Oncology deals with the study of cancer. Within oncology there are several sub-specialities that deal with different types of cancer.
Different cancers affecting different parts of the body e.g. breast, prostate, lungs, blood cells (leukemia) or other organs behave in different manner, are of different grades and cellular type, respond differently to treatment and have different set of effective treatment regimen.
This mandates the need for different specialities of oncologists and does away with a “one size fits all” approach. Cancer-care, however, is a multidisciplinary approach and consists of a team of professionals who help in the treatment of the patient.