Oncology is a branch of study and treatment of cancer. Cancer is disease in which abnormal cells grow and divide without control. Oncology drugs help in diagnosis cancer. Some of the causes of cancer are tobacco and smoking, viral infections, genetic causes, carcinogens, bacterial infections, physical activities, eating habits and age. Various types of cancer that can be treated by oncology drugs are blood cancer, endocrine cancer, lung cancer, bone cancer, skin cancer, genitourinary cancer, gastrointestinal cancer, breast cancer, eye cancer, head and neck cancers and gynaecologic cancer. On the basis of treatment, oncology drugs market can be segmented into chemotherapy, immunotherapy, surgery, radiation therapy, stem cell transplant, hormone therapy and others.