What Does an Oncologist Do? A Comprehensive Guide to Cancer Specialists

An oncologist is a physician who specializes in diagnosing, staging, and treating cancer. When you receive a cancer diagnosis, the oncologist creates a personalized treatment plan based on detailed pathology reports that identify the cancer type, stage, growth rate, and locations involved.

Cancer care often involves multiple modalities, so you may work with several types of oncologists throughout treatment.

Medical Oncologists

Medical oncologists manage cancer with chemotherapy, hormonal therapy, immunotherapy, and other targeted drugs. They are typically the primary point of contact for patients, coordinating care, monitoring side effects, and providing ongoing follow‑up after treatment ends.

Radiation Oncologists

Radiation oncologists deliver high‑energy radiation to destroy cancer cells. Approximately 50% of patients receive radiation as part of their regimen. Techniques range from external‑beam radiation to brachytherapy (tiny radioactive seeds) and highly focused “radiosurgery.”

Surgical Oncologists

Surgical oncologists often perform the first diagnostic biopsy and, when appropriate, surgically remove tumors and surrounding tissue. They also guide pre‑operative preparation and post‑operative recovery.

Pediatric Oncologists

Pediatric oncologists treat children with cancer. Worldwide, about 175,000 children under 15 are diagnosed each year, and in the United States roughly 80% of them survive. Many pediatric oncologists also conduct research and provide extensive education to families.

Gynecologic Oncologists

Gynecologic oncologists focus on cancers of the female reproductive system—ovarian, cervical, uterine, vaginal, and vulvar—as well as complex non‑cancerous gynecologic conditions such as endometriosis and fibroids.

Hematologist‑Oncologists

These physicians treat blood‑related cancers, including leukemia and lymphoma, and may also manage non‑malignant blood disorders like sickle‑cell disease and hemophilia.

WHAT TO BRING WITH YOU

• A friend or family member. A supportive companion can help you absorb information and take notes.
• Medical records. Bring imaging reports, pathology results, and a complete list of medications and supplements.

What to Expect at Your First Appointment

Initial oncology visits often last two to three hours to allow thorough information gathering. You can expect:

• Emotional responses. Anxiety, anger, sadness, or even shock are normal reactions.
• A physical exam. The oncologist will conduct a focused exam even if you’ve already seen your primary‑care doctor.
• Additional tests. Blood work, imaging, or repeat biopsies may be ordered.
• Introductions to the care team. You may meet nurses, social workers, or financial counselors.
• Preliminary prognosis. The doctor may provide an early outlook based on current findings.

Questions to Ask Your Oncologist

Preparing a list of questions helps you stay organized and ensures you receive the information you need. The MD Anderson Cancer Center recommends asking:

• What specific information are we hoping to obtain from these tests?
• Why is this treatment recommended for me?
• What side effects should I anticipate?
• How successful has this approach been for other patients with similar disease?
• When can I expect to return to work or normal activities?
• Can you explain that again in plain language?
• Are there clinical trials that might be appropriate for me?

Oncologists may perform a physical exam, order blood and urine tests, and request imaging such as MRI, CT, or ultrasound. Biopsies are often needed to confirm cancer cells.

Becoming an oncologist requires extensive training. After medical school, physicians complete a three‑year internal‑medicine residency, followed by a two‑ to three‑year fellowship in medical oncology. Surgical oncologists finish a general‑surgery residency and a two‑year oncology fellowship. Radiation oncologists undergo a five‑year pathway that includes an internal‑medicine internship and a dedicated radiation‑oncology residency.

To find a qualified oncologist, start with a referral from your primary‑care physician, verify network participation, and consider cancer centers accredited by the American College of Surgeons’ Commission on Cancer. The American Cancer Society’s hospital checklist can also guide you to reputable facilities.

In summary, oncologists are highly trained physicians who diagnose and treat cancer through medical, surgical, radiation, pediatric, gynecologic, or hematologic specialties. Expect a multidisciplinary approach, thorough testing, and a collaborative care team designed to give you the best possible outcome.