Hematology is the branch of medicine devoted to the study of blood. Oncology is the study of cancer, a class of diseases that causes uncontrolled growth of cells. Some tumors are benign, which means they don't invade or hurt other areas of the body. A malignant means the tumor (mass of cells) destroys or invades other areas. While these two specialties are separate, they commonly overlap. Oncologists and hematologists frequently work together to provide integrated care. For instance, bone marrow transplants are blood related, but may be used in treating some cancers. Also, some blood tests are used to identify some forms of cancer.

Your primary-care provider will refer you to a hematologist or oncologist if your condition requires this specialized care.

There are many oncologic and hematologic diseases, including but not limited to: