Oncologist Say: on-kah-luh-jist This is a doctor who treats patients who have cancer. Oncologists who treat kids who have cancer are called pediatric oncologists. Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.