Oncology is the branch of medicine that researches, identifies and treats cancer. A physician who works in the field of oncology is an oncologist.

Oncologists must first diagnose a cancer, which is usually carried out via biopsy, endoscopy, X-ray, CT scanning, MRI, PET scanning, ultrasound or other radiological methods. Nuclear medicine can also be used to diagnose cancer, as can blood tests or tumor markers. Oncology is often linked with hematology, which is the branch of medicine that deals with blood and blood-related disorders.


Once a diagnosis is made, the oncologist discusses disease stage with the patient. Staging will dictate treatment of the cancer. Chemotherapy — which is defined as the destruction of cancer cells — may be used, as well as radiation therapy. Surgery is used to remove tumors. Hormone therapy is used to treat certain types of cancers, and monoclonal antibody treatments are gaining popularity. Research into cancer vaccines and immunotherapies is ongoing. Palliative care in oncology treats pain and other symptoms of cancer.

Treatment team 

Cancer is often treated in a team effort, with at least two or three types of oncologists, including medical, surgical or radiation. The oncology treatment team may also include a pathologist, a diagnostic radiologist or an oncology nurse. In the event of a new or a difficult-to-treat case of cancer, the oncology care team may consult a tumor board, made up of various medical experts from all relevant disciplines. The tumor board reviews the case and recommends the best course of cancer treatment for the patient.