Endocrine Oncology is the treatment of Endocrine cancers and tumors affecting hormone regulation. Endocrine cancer is a group of different types of cancer that impact the endocrine system. A tumor begins when normal cell in the body change and grow uncontrollably, forming a mass. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can spread to other parts of the body. A benign tumor means the tumor will not spread. An endocrine tumor is a mass that affects the parts of the body that secrete hormones. Because an endocrine tumor starts in the cells that make hormones, the tumor itself can make hormones and cause serious illness. Chemotherapy is the use of drugs to destroy tumor cells, usually by stopping the cells’ ability to grow and divide. Chemotherapy is given by a medical oncologist, a doctor who specializes in treating tumors with medication. Systemic chemotherapy is delivered through the bloodstream to reach cancer cells throughout the body. Common ways to give chemotherapy include an intravenous (IV) tube placed into a vein using a needle or in a pill or capsule that is swallowed (orally).