Oncology is the branch of medicine dealing with tumors (cancer). A medical professional who practices oncology is an oncologist. The term originates from the Greek onkos ...
Gastroenterology is the branch of medicine whereby the digestive system and its disorders are studied. Etymologically, the name is a combination of three Ancient Greek words gastros (stomach), enteron (intestine), and logos (reason).
Diseases affecting the gastrointestinal tract, which includes the organs from mouth to anus, along the alimentary canal, are the focus of this specialty.