Gynecologic Oncology: might also be known as a gynecologic oncologist. This is a physician who specializes in diagnosing and treating cancers that are located on a woman's reproductive organs. This person serves as the captain of a woman's gynecologic cancer care team. In order to become a gynecologic oncologist a physician must first complete an approved, 4-year residency program in obstetrics and gynecology. Following this, he/she must complete a 2-4 year clinical fellowship in gynecologic oncology.