Health Library

What Are Hematology and Oncology?

Hematology (hee-muh-TOL-uh-jee) is the medical specialty that treats diseases and problems relating to blood, including blood cells and vessels, lymph nodes, and bone marrow.

Oncology (on-KOL-uh-jee) is the medical specialty that studies and treats cancer.

Hematology-oncology (often called hem-onc) is the study, diagnosis, treatment, and prevention of blood diseases and cancer.

What Are Hematologist-Oncologists?

A hematologist-oncologist is a doctor who specializes in blood diseases, bleeding disorders, and cancers. They’re trained in hematology and oncology.

Why Would Someone Need One?

Hematologist-oncologists diagnose and treat many different conditions, including: 

• sickle cell disease
• anemia
• neutropenia
• hemophilia
• hepatocellular carcinoma
• leukemia
• lymphoma
• thalassemia
• thrombocytopenia

What Do Hematologist-Oncologists Do?

They provide treatments such as:

• bone marrow (stem cell) transplant
• blood transfusions
• chemotherapy
• immunotherapy
• proton therapy
• radiation therapy
• surgery
• gene therapy

What Is Their Training?

Hematologist-oncologists who treat kids and teens have training that typically includes:

• 4 years of pre-medical education at a college or university
• 4 years of medical school — a medical degree (MD) or doctor of osteopathic medicine (DO) degree
• 3 years of training in an internal medicine residency program
• 3 years of pediatric hematology/oncology training in a fellowship program. A “fellow” is a doctor who had more specialty training after completing medical school and residency training.

They also might have expertise in a specific blood disorder or type of cancer.

Good to Know

Some hematologist-oncologists treat also solid tumors, such as retinoblastoma, melanoma, and Wilms tumor.