An oncologist is a doctor who specializes in diagnosing, staging, and treating cancer. These physicians manage care from the moment cancer is suspected through treatment and long-term follow-up, coordinating everything from initial testing to post-treatment monitoring. If you or someone you know has been referred to one, understanding what they do and how they fit into cancer care can make the process feel less overwhelming.
What an Oncologist Does
An oncologist’s role covers the full arc of cancer care. They run or order diagnostic tests, confirm whether cancer is present, identify what type it is, determine how far it has spread (staging), and then lay out a treatment plan. But the job goes well beyond choosing treatments. Oncologists review your complete medical history, weigh your overall health, and factor in the specific traits of your cancer, including how abnormal the cells look under a microscope and whether they carry certain genetic changes or hormone receptors that influence how the cancer behaves.
Once treatment begins, your oncologist oversees the process, adjusts the plan based on how you respond, manages side effects, and coordinates with other specialists. After treatment ends, they remain your primary cancer doctor for long-term checkups to watch for recurrence.
Types of Oncologists
Not all oncologists do the same work. The field breaks into several core specialties, each focused on a different approach to treating cancer.
- Medical oncologists are typically trained in internal medicine and treat cancer using chemotherapy, immunotherapy, targeted therapy, and hormone therapy. They usually serve as the lead physician on your care team, developing your overall treatment plan and coordinating with other specialists.
- Surgical oncologists are surgeons who specialize in removing cancerous tumors, surrounding tissue, and performing biopsies.
- Radiation oncologists treat cancer using radiation therapy to shrink or destroy cancer cells, or to relieve cancer-related symptoms.
- Gynecologic oncologists focus on cancers of the female reproductive system, including uterine, cervical, and ovarian cancers.
Beyond these, further subspecialties exist. Pediatric hematology-oncologists treat blood cancers and solid tumors in children. Neuro-oncologists focus on cancers of the brain and nervous system, and they typically complete additional fellowship training beyond a standard oncology program. Hematology-oncologists specialize in blood cancers like leukemia, lymphoma, and myeloma.
Training and Certification
Becoming an oncologist requires one of the longest training paths in medicine. After four years of medical school, a physician completes a three-year residency in internal medicine (or surgery, for surgical oncologists). Then comes a fellowship in their oncology subspecialty, which typically lasts another three years. Some physicians add a fourth or fifth fellowship year for further specialization. All told, an oncologist’s training after college spans at least 10 to 11 years.
To practice as a board-certified medical oncologist in the United States, a physician must hold a current internal medicine certification from the American Board of Internal Medicine, complete an accredited fellowship, hold an unrestricted medical license, and pass the Medical Oncology Certification Examination.
Treatments Oncologists Manage
Cancer treatment has expanded significantly beyond traditional chemotherapy. A medical oncologist may recommend one or more of the following approaches, depending on the type and stage of your cancer:
- Chemotherapy: drugs that kill fast-growing cells throughout the body.
- Immunotherapy: treatments that help your own immune system recognize and attack cancer cells.
- Targeted therapy: drugs that zero in on specific changes inside cancer cells that help them grow and spread, while doing less damage to healthy tissue.
- Hormone therapy: used for breast and prostate cancers that depend on hormones to grow, this treatment slows or stops that growth.
- Surgery: removal of tumors and affected tissue, handled by a surgical oncologist.
- Radiation therapy: high-energy beams directed at cancer cells, managed by a radiation oncologist.
Many patients receive a combination of these. Your medical oncologist is typically the one coordinating these different pieces into a single plan.
What Happens at Your First Appointment
A first oncology visit is mostly about gathering information. Your oncologist will ask you to walk through your story: when you first noticed symptoms, what tests you’ve already had, and what your referring doctor told you. This conversation helps them confirm what’s already been collected and gives them a sense of your concerns and priorities. A short physical exam is standard.
Bring a list of every medication you take, including over-the-counter pain relievers, vitamins, herbs, and supplements. Your oncologist needs this to check for potential interactions before recommending any treatment.
If enough diagnostic information is available, your oncologist will discuss treatment options during that first visit, explaining what’s available, how effective each approach is, and what side effects to expect. They’ll recommend a course of action and give you time to ask questions. In many cancer centers, your case is then reviewed at a weekly meeting attended by multiple cancer specialists, who develop a consensus plan for your care.
The Broader Care Team
An oncologist doesn’t work alone. Cancer care involves a multidisciplinary team that typically includes at least four different medical specialists. Pathologists analyze tissue samples to confirm a diagnosis. Radiologists interpret imaging scans. Oncology nurses and specialist nurses play a central role in day-to-day care and patient support. Psychologists and social workers address the emotional and practical challenges that come with a cancer diagnosis. Your general practitioner often stays involved as well, serving as an outside participant in your care team.
How Oncologists Estimate Prognosis
One of the most important conversations you’ll have with an oncologist involves prognosis, which is their best estimate of how your cancer will respond to treatment and progress over time. They base this on statistics collected over many years from people with the same type and stage of cancer, combined with individual factors: where the cancer is in your body, how quickly it appears to be growing, your age, your overall health before diagnosis, and how you respond to initial treatment.
A prognosis is an educated estimate, not a certainty. Your oncologist might describe it as “good” if the data suggests your cancer is likely to respond well to treatment, or “poor” if the cancer tends to be harder to control. But outcomes vary from person to person, and statistics describe populations, not individuals. If you want to understand your prognosis in detail, your oncologist is the person best positioned to explain what the numbers mean for your specific situation.
Growing Demand for Oncologists
The oncology workforce is under increasing pressure. More than half of medical oncologists in recent surveys have exceeded the median target of 175 new patient consultations per year. Workforce projections for radiation oncology forecast a deficit in providers by 2026. As cancer diagnoses rise with an aging population, this shortage is pushing the field to find more efficient ways to deliver care while maintaining quality.