What is an oncologist?

This page was reviewed under our medical and editorial policy by

Vijay Trisal, MD, Chief Medical Officer; Surgical Oncologist, City of Hope | Duarte

This page was updated on July 18, 2023.

A board-certified oncologist is cancer specialist, or a doctor trained to diagnose and treat cancer. If you’re receiving cancer care, or your care team is determining a diagnosis, you may be working with oncologists a lot.

What does an oncologist do?

You probably already know there are many forms of cancer, and all sorts of people who develop cancer, from young to old. So it makes sense that there’s no one-size-fits-all for the field of oncology and cancer care. Some oncologists are experts in certain cancers, treatments or populations. Oncologists may also engage in clinical research or teach medical students as ways to contribute to cancer care beyond seeing patients.

An oncologist may:

  • Make a diagnosis. An oncologist will tell you whether you have cancer and, if so, explain the type, stage and site of the tumor. 
  • Order tests. An oncologist looks to tests—such as blood tests, urine tests, imaging or biopsies—to diagnose cancer or check to see whether it’s spread.
  • Oversee treatment. An oncologist makes and oversees a treatment plan, using one or more types of therapies such as radiation, surgery, chemotherapy, immunotherapy and targeted therapy.
  • Monitor and refer. In helping you manage the treatment’s effects, an oncologist may provide referrals to other providers, like behavioral health therapists.
  • Make a follow-up plan. It’s important for patients to have a care plan after treatment is complete.
  • Answer questions. An oncologist is there to answer whichever questions you may have about your cancer and treatment.

If another provider refers you to an oncologist, you may have a wide range of understandable emotions, including anxiety or fear. Sometimes, knowing more about a provider, such as what type of training they’ve had and what to expect from a visit, may help ease your fears. Keep in mind that many times, an oncologist is ruling out cancer.

Types of oncologists

Board-certified oncologists are experts and specialists in specific types of cancer or treatment methods. Because you may get more than one type of treatment, your care team may include multiple oncologists.

Below are some of the most common oncologists:

  • Medical oncologists diagnose and treat cancer while coordinating care with other physicians and providers in the care team as needed.
  • Surgical oncologists are surgeons. They’re experts in doing biopsies and surgical procedures such as tumor removals.
  • Radiation oncologists will handle radiation treatment if that therapy is a part of the treatment plan.
  • Gynecologic oncologists diagnose and treat cancers in reproductive organs, such as ovarian and uterine cancers. Gynecologic oncologists may also see people for issues unrelated to cancer, such as endometriosis, where uterine cells grow in unexpected areas outside the uterus.
  • Pediatric oncologists are the doctors who diagnose and treat children who have cancer. Because some cancers are more common in children or teenagers, like leukemia, adults with these cancers may choose a pediatric oncologist for their care.
  • Hematologic oncologists are experts in treating blood cancers, such as leukemia, lymphoma and myeloma.
  • Urologic oncologist are doctors who treat cancers of the urinary tract and the reproductive organs.

How oncologists are trained

After completing medical school and residency and passing all required tests and licensing exams, doctors may choose to continue with additional training to become an oncologist. Oncology training typically requires two to four years of oncology-focused fellowship training at an accredited program, but it may take a number of years of additional training, depending on the specialty and the number of fellowships the physician completes.

What to expect and what to ask

If you’re meeting an oncologist for the first time, here’s what you should expect:

  • A review of your medical history, including tests or scans you’ve had and any family history of cancer. If you have a family history of cancer, the oncologist may ask you details such as your relationship to the person, as well as your relative’s age of diagnosis, treatment and reaction to treatment. They’ll ask what medications—if any—you’re taking and if you have a history with substances such as cigarettes and alcohol.
  • A discussion about how to diagnose or rule out your type of cancer. Using evidence-based guidelines, the oncologist determines the proper manner of diagnosis for that tumor and recommends testing. If you’ve already had diagnostic testing, the oncologist also determines how much of the diagnostic process has already occurred and uses evidence-based guidelines to recommend additional tests or potential therapies. The oncologist may outline your treatment plan or recommend changes to it.
  • A head-to-toe physical examination, which may involve taking vital signs like your pulse and blood pressure. This examination may happen at every appointment.
  • A review of the medical data in your chart to make sure all essential details are recorded and you have a good idea of what’s in your comprehensive chart. The oncologist may review it with you orally, and you may receive an email to review it in your patient portal.

This is also a chance to ask any questions you may have.

Below are some helpful ideas for questions to ask your oncologist:

  • What type of cancer do I have?
  • Has the cancer spread at all?
  • Do I need to have more tests before starting treatment?
  • If so, which tests?
  • Why do you think this treatment plan is best for me?
  • When will I start my treatment?
  • What side effects may I have?
  • How will we know whether the treatment is working?
  • Will I be seeing any other providers?
  • If so, do you provide the referral, and do you know if they take my insurance?
  • Should I participate in a clinical trial? Why or why not?
  • What mental health resources are available to me?

How to find an oncologist

If you don’t have an oncologist already, you’ll want to find one that you trust and feel comfortable with. Common ways to find the right oncologist for you include:

  • Referrals. A primary care provider or your medical oncologist may provide a referral to an oncologist. If you know someone who’s had cancer care before, consider asking for a recommendation.
  • Directories. Hospitals and insurance providers likely have listings of oncologists in your area and network. The American Medical Association offers a search tool to find doctors in the United States. To make sure an oncologist you’re considering is board certified, use the online search tool from the American Board of Medical Specialties, American Society of Clinical Oncology, Society of Surgical Oncology or American Society of Radiation Oncology.
  • Interviews. Personal connections are important—you want customized care and to feel heard. Before choosing an oncologist, think about having a conversation. Ask about that oncologist’s experience, number of patients, and treatment guidelines. You may meet with more than one oncologist and choose the one who suits you.

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Show references
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  • National Cancer Institute (2021, January 26). Follow-Up Medical Care.
  • U.S. National Library of Medicine (2020, November 2018). Endometriosis.
  • American College of Physicians. Oncology.
  • American Society of Clinical Oncology (2018, March). Types of Oncologists.
  • American Society of Clinical Oncology (2015, August 4). Contemporary Clinical Oncology Training in the United States: Is Radiation or Medical Oncology Right for You?
  • Journal of Advanced Practical Oncology (2014, Jul-Aug) The History and Physical in Cancer Care: A Primer for the Oncology Advanced Practitioner
  • National Cancer Institute. Questions to Ask Your Doctor about Cancer.
  • Susan G. Komen. Choosing a Doctor.
  • National Cancer Institute (2020, November). Finding Healthcare Services.