Oncologist: Your Cancer Treatment Specialist

Medically Reviewed By William C. Lloyd III, MD, FACS
Was this helpful?

What is an oncologist?

An oncologist specializes in diagnosing, treating and preventing cancer. Oncologists provide medical and pain management care for adults who have cancer or precancerous signs or risk factors. A pediatric hematologist-oncologist treats children with cancer.

Oncologists often work with patients as part of cancer healthcare teams that include surgeons, radiologists, pathologists, nurses, and social workers. An oncologist typically:

  • Evaluates a patient’s medical history and educates the patient about the type of cancer involved

  • Provides a care plan for cancer treatment

  • Leads or collaborates with cancer healthcare teams that include surgeons, radiologists, pathologists, nurses, and social workers who provide various care and services for patients during and after treatment

  • Orders and interprets laboratory, imaging, genetic and surgical tests to confirm and analyze the presence of cancer

  • Orders or provides medical treatments to eliminate cancer, such as medication therapy, chemotherapy, radiation therapy, and immunotherapy

  • Orders or provides palliative therapies, such as medications and physical therapy to manage pain and symptoms

  • Recommends surgery to remove cancer and precancerous cells

Oncologists may also be known by the following names: medical oncologist, oncology doctor, cancer doctor, or cancer specialist.

Who should see an oncologist?

People with cancer see an oncologist on a regular basis to monitor the progression and treatment of cancer, as well as manage their symptoms. People who are newly diagnosed with cancer by a primary care doctor, surgeon, or other doctor should seek care from an oncologist as soon as possible to begin exploring further diagnostic procedures and treatment options. As with many diseases, the sooner cancer is treated, the higher the likelihood that it can be effectively managed and hopefully cured.

When should you see an oncologist?

You should seek care from an experienced oncologist when a primary care doctor, gynecologist, surgeon, or other doctor has diagnosed you with cancer or suspects that you have cancer. The doctor who diagnosed you should discuss with you the type of cancer, its location, and whether it appears to have spread. He or she will help you choose an oncologist with whom you can consult about further tests, reach a final diagnosis, and design a treatment plan.

You can also request a referral to an oncologist for a second opinion regarding a cancer diagnosis and suggested treatment plan.

What conditions and diseases does an oncologist treat?

Oncologists treat many different types of cancer, although most individual oncologists focus their practice on a smaller group of related malignancies:

What tests does an oncologist perform or order?

An oncologist can order or perform a wide variety of diagnostic and screening tests for the presence of cancer. These tests include:

  • Genetic tests to detect gene mutations that are linked to cancer

  • Imaging tests including mammograms, computed tomography (CT) scans, and magnetic resonance imaging (MRI)

  • Laboratory tests of urine, blood and biopsies such as a lymph node biopsy for signs of cancer

  • Physical exams to look for outward signs of malignancy, such as lumps or skin changes

An oncologist may advise surgery to diagnose the presence and the extent of cancer cells. Diagnostic surgery includes biopsies to remove a small amount of tissue as well as minimally invasive (laparoscopic) surgery, which allows the surgeon to see inside your body for signs of cancer.

What procedures and treatments does an oncologist perform or order?

Medical oncologists specialize in the treatment of cancer with medicine. They do not perform surgery to remove cancer. However, they oversee and manage the surgical care provided by general surgeons and surgical oncologists. In addition, they often coordinate the care provided by the entire team of cancer specialists who are treating the patient, including the surgeon, radiation oncologist, and pathologist. A pathologist examines biopsies to diagnose the specific type of cancer, a radiation oncologist uses radiation to kill cancer cells, and surgeons surgically remove cancer.

The specific procedures and treatments performed or ordered by medical oncologists include:

  • Catheter or port insertion for chemotherapy and blood tests. A surgeon inserts a semipermanent catheter or port through which you receive chemotherapy and other medications as part of cancer treatment.

  • Medical treatments including chemotherapy and immunotherapy to cure or stop the spread of cancer

  • Palliative therapies including medications and physical therapy to manage pain and symptoms

Oncologist training and certification

A doctor may practice oncology without becoming board certified. However, education, training, experience and certification are key elements in establishing a doctor’s level of competence. Board certification verifies that a doctor has completed residency training in the specialty and has passed competency examinations.

A board-certified oncologist has earned certification in medical oncology by the American Board of Internal Medicine or in oncology by the American Osteopathic Board of Internal Medicine.

A board-certified oncologist has:

  • Graduated from medical school or a college of osteopathic medicine, earning an MD or DO degree

  • Completed specialized residency training in internal medicine
  • Passed a certification exam that validates the doctor’s knowledge and skills in internal medicine

  • Completed specialized fellowship training in medical oncology, diagnosing and managing cancer with medicine

  • Passed a written certification exam that validates the doctor’s specialized knowledge and skills in medical oncology

To maintain board certification in medical oncology, a doctor must participate in an ongoing certification program.
In addition to oncology, doctors can train, earn board certification, and practice in the following oncology-related subspecialties:

  • Complex general surgical oncology focuses on the diagnosis and care of patients with complex cancer, or cancer that involves multiple organ systems. The American Board of Surgery recently announced this board certification.

  • Gynecologic oncology focuses on the medical and surgical care of cancer affecting the female reproductive organs. The American Board of Obstetrics and Gynecology and the American Osteopathic Board of Obstetrics and Gynecology offer board certification in gynecologic oncology.

  • Pediatric hematology and oncology focuses on the medical care of cancer in infants and children. The American Board of Pediatrics offers board certification in pediatric hematology and oncology.

  • Radiation oncology focuses on the use of radiation to treat cancer. The American Board of Radiology and the American Osteopathic Board of Radiology offer board certification in radiation oncology.

Was this helpful?
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2017 Nov 8
View All Cancer Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Subspecialty Certification in Oncology. American Osteopathic Board of Internal Medicine. https://certification.osteopathic.org/internal-medicine/certification-process-overview/oncology/.  
  2. Oncology. American College of Physicians. https://www.acponline.org/about-acp/about-internal-medicine/subspecialties/oncology.  
  3. The Oncology Team. Cancer.net. http://www.cancer.net/patient/All+About+Cancer/Newly+Diagnosed/The+Oncology+Team.  
  4. Types of Oncologists. Cancer.net. http://www.cancer.net/patient/Publications+and+Resources/Find+an+Oncologist/Types+of+Oncologists.  
  5. What is Cancer Screening? National Cancer Institute. http://www.cancer.gov/cancertopics/pdq/screening/overview/patient/.  
  6. Just Diagnosed. Women’s Cancer Network. http://www.wcn.org/articles/treatment/gynecologic_oncologists/overview/.  
  7. Complex General Surgical Oncology Qualifying Exam. American Board of Surgery. http://www.absurgery.org/default.jsp?certsurgoncqe.