Oncologists, like many physicians, divide their time between patient consultations, medical procedures, study, research, publishing, and office or departmental administration. Most oncologists work more than 40 hours per week. Oncologists may see anywhere from 10 to 30 patients each day.

Medical oncologists specialise in the treatment of cancer with systemic anticancer therapies, whereas clinical oncologists perform the same role but are also qualified to use radiotherapy. Cancer treatment is extremely varied and complex and depends on each patient's circumstances.

The traditional route to becoming an oncology specialist is to start by completing a three-year US medical residency program in internal medicine before completing a three-year fellowship in Hematology and Oncology or (less commonly) a two-year fellowship program in Oncology.

A doctor who has special training in diagnosing and treating cancer in adults using chemotherapy, hormonal therapy, biological therapy, and targeted therapy. A medical oncologist often is the main health care provider for someone who has cancer.