March 02, 2022
2 min read

What is an oncologist?

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An oncologist is a physician who specializes in the field of oncology, the branch of medicine that diagnoses and treats cancer.

Oncologists work in three main fields radiation, surgical and medical. A medical oncologist is typically the main health care provider for someone who has cancer but also gives supportive care, coordinating treatments given by other specialists.

Photo of cancer cell

Other common oncology specialties include:

  • gynecologic — which deals with the treatment of women with cancer of the female-specific organs;
  • neuro – which treats cancers of the brain, spine and nervous system;
  • thoracic – which deals with inside the chest area, such as the lungs and esophagus;
  • urologic – which treats the genitourinary system, like the bladder, kidneys, penis, prostate gland and testicles;
  • pediatric — which is related to the treatment of children and teens with cancer; and
  • geriatric – which is related to the treatment of adults 65 years of age and older.

Diagnosis and treatment of blood cancers, like leukemia and lymphoma, fall under the hematology-oncology specialty.

Becoming an oncologist

The training required to become an oncologist — and later to become a subspecialist in medical oncology, radiation oncology or other disciplines — is extensive.

The requisite 4 years of premedical education at a college or university is followed by 4 years in medical school to earn an MD or DO, and then postgraduate training is obtained through internships or residencies, typically taking about 3 to 4 years.

Following residency, a fellowship in a subspecialty, for at least 2 years, is needed before obtaining a license. After fulfilling these requirements, physicians must pass an examination to become board certified as a specialized oncologist. Depending on the physician’s subspecialty, testing and certification is conducted by one of the following:

  • American Board of Obstetrics and Gynecology (ABOG);
  • American Board of Internal Medicine (ABIM);
  • American Board of Pediatrics (ABP);
  • American Board of Radiology (ABR); or
  • American Board of Surgery (ABS).

Oncologists additionally must pass an exam to gain a license to legally practice in their state. Subspecialists in medical oncology or radiation oncology must have at least 1 additional year of training in those fields.

Oncologist job description

Oncologists diagnose cancer using biopsy, endoscopy, X-ray, CT scanning, MRI, PET scanning, ultrasound or other radiologic methods. Nuclear medicine, as well as blood tests and tumor markers, are also used for diagnosis.

Once cancer has been diagnosed, oncologists discuss the disease type and stage with the patient. Staging helps dictate the type of cancer treatment the patient receives. Staging tests and procedures may include bone scans or X-rays to see if the cancer has metastasized, or spread to other parts of the body.


A pathologist is a physician who examines cells and tissues under a microscope, and then writes the pathology report. A pathology report explains a cancer diagnosis and stage of disease. This information helps to determine treatment for the patient. Pathologists typically send the pathology report to the oncologist within 10 days after biopsy or surgery.

Oncology treatment

Oncologists oversee and coordinate oncology treatment and specialize in the use of medications, such as chemotherapy, hormones and analgesics to manage disease. Oncologists often coordinate care with radiation and surgical oncologists.

There are many types of cancer treatment. Some patients will require only one form of treatment. Depending on the stage and the type of cancer, some will require a combination of the following treatments:

  • surgery;
  • chemotherapy;
  • radiation therapy;
  • targeted therapy;
  • immunotherapy;
  • stem cell or bone marrow transplant; or
  • hormone therapy.

Radiation oncologists use high-energy X-rays, gamma rays, neutrons, protons and other sources to destroy cancer cells. Radiation can be given as curative treatment or in combination with chemotherapy and/or surgery. Patients with incurable cancers may also be seen by radiation oncologists for symptom relief, known as palliative treatment.

Surgical oncologists are surgeons who specialize in the surgical treatment of cancer and malignant disease. They work closely with oncologists either before or after surgical removal of tumors to provide effective care.

Compared with nonsurgical oncology, the training for surgical oncologists is highly competitive and requires general surgery residency training. Palliative care may also be used by oncologists to treat pain and other symptoms of cancer, focusing on quality of life for the patient and their family.

Additional information can be found by searching the following websites: