Medical oncology treats breast, lung, gastrointestinal, and gynaecological cancers mainly using medicines that travel through the bloodstream to find and attack cancer cells anywhere in the body. For breast cancer, treatment depends on the type of cancer and may include hormone medicines, targeted drugs, or immunotherapy. For lung cancer, doctors now use special tests to choose medicines that target specific changes in cancer cells or help the body’s own immune system fight the disease, sometimes instead of regular chemotherapy. For gastrointestinal cancers such as colorectal and pancreatic cancer, treatment often includes medicines to shrink the tumour first and then surgery if needed. For gynaecological cancers like ovarian, cervical, and uterine cancer, treatment usually involves chemotherapy along with newer medicines that stop cancer cells from repairing themselves, and in some cases, immunotherapy for advanced disease.