Oncology:- ♦ What is Oncology?? (What is oncology?? Oncology is the branch of medicine that deals with the diagnosis and treatment of cancer. A person who is associated with the practice of Oncology is called an oncologist. Oncology is ONKOS MEANING= BULK, MASS, TUMOR. LOGY MEANING: = STUDY OF Words have come together Oncology. There are three main branches of Oncology. 1) Medical oncology: In this treatment starts with drugs