An oncologist is a medical doctor who specializes in the treatment of cancer.  There are typically three types of oncologists who work together to help treat a patient with cancer - a medical oncologist (who focuses on treating cancer with medication such as chemotherapy), a surgical oncologist (who focuses on removing cancer surgically) and a radiation oncologist (who focuses on treating cancer with various types of radiation). The American Society of Clinical Oncology (ASCO) also recognizes gynecological oncologists (who specialize in cancers of the female reproductive organs), pediatric oncologists (who specialize in treating children with cancer), and hematological oncologists (who specialize in cancers of the blood like leukemia). Becoming an oncologist will be ambitious, challenging, and arduous. But maybe more importantly being an oncologist will be rewarding, stimulating, and worthwhile.