Oncology — Find Specialists & Top Hospitals Worldwide | MyMedicPlus

Oncology is the branch of medicine dedicated to the study, diagnosis, treatment, and prevention of cancer. Cancer is not a single disease but a collection of more than 100 distinct conditions characterised by uncontrolled cell growth and the ability to invade and spread to other tissues. Oncologists are the physicians who specialise in delivering cancer-directed treatments and coordinating the complex multidisciplinary care that modern cancer management demands.

The specialty is divided into three broad categories. Medical oncology uses systemic drug-based treatments including chemotherapy, hormonal therapy, targeted molecular therapy, and immunotherapy. Radiation oncology delivers ionising radiation with extraordinary precision to destroy cancer cells while protecting surrounding healthy tissue. Surgical oncology specialises in the safe removal of tumours, sentinel lymph node biopsy, and cytoreductive procedures for a wide range of cancer types.

Modern oncology has been transformed by advances in molecular biology and genomics. Comprehensive tumour profiling — testing for specific mutations, gene fusions, and protein expressions — now guides selection of targeted agents that attack cancer-specific molecular vulnerabilities rather than broadly killing all dividing cells. Immunotherapy, particularly checkpoint inhibitor drugs, has produced durable remissions in cancers previously considered untreatable, including advanced melanoma, non-small cell lung cancer, and Hodgkin lymphoma. Cancer care is best delivered by multidisciplinary tumour boards where oncologists, surgeons, radiologists, pathologists, and palliative care specialists collaborate on each patient's plan.

Oncologists diagnose and treat the full spectrum of human cancers, including:

• Breast cancer: The most common cancer in women worldwide; treatment depends on hormone receptor status, HER2 expression, and genetic testing (BRCA1/2), combining surgery, radiation, chemotherapy, and targeted agents.
• Lung cancer: Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC); NSCLC is routinely profiled for EGFR, ALK, ROS1, and KRAS mutations guiding targeted therapy selection.
• Colorectal cancer: Cancers of the colon and rectum requiring coordination of surgery, chemotherapy, and radiation; MSI-H/dMMR status guides immunotherapy eligibility.
• Prostate cancer: Hormone-sensitive and castration-resistant prostate cancer managed with androgen deprivation therapy, ARSI agents, chemotherapy, and PARP inhibitors.
• Haematological malignancies: Including acute and chronic leukaemias (ALL, AML, CLL, CML), Hodgkin and non-Hodgkin lymphomas, and multiple myeloma, managed by haematologist-oncologists.
• Melanoma: Advanced melanoma treated with BRAF/MEK targeted inhibitors or checkpoint immunotherapy (anti-PD-1, anti-CTLA-4 antibodies).
• Ovarian cancer: High-grade serous ovarian cancer treated with surgery, platinum-based chemotherapy, and PARP inhibitors in BRCA-mutated disease.
• Pancreatic cancer: Aggressive adenocarcinoma with limited treatment options, managed with chemotherapy (FOLFIRINOX, gemcitabine) and assessed for surgical resectability.
• Liver and biliary tract cancers: Hepatocellular carcinoma and cholangiocarcinoma managed with targeted therapies, immunotherapy, and locoregional interventions.
• Brain tumours (neuro-oncology): Glioblastoma and lower-grade gliomas managed with surgery, radiation, and temozolomide chemotherapy.

Oncologists administer and supervise a broad range of cancer-directed and supportive interventions:

• Systemic chemotherapy: Intravenous or oral cytotoxic drugs that kill rapidly dividing cancer cells; commonly used regimens include FOLFOX, CHOP, AC-T, and platinum-based doublets.
• Targeted molecular therapy: Drugs designed to block specific cancer-driving mutations or proteins — examples include imatinib (CML), trastuzumab (HER2+ breast cancer), osimertinib (EGFR-mutant lung cancer), and vemurafenib (BRAF-mutant melanoma).
• Immunotherapy (checkpoint inhibitors): Anti-PD-1 (pembrolizumab, nivolumab) and anti-CTLA-4 (ipilimumab) antibodies that release immune system brakes, allowing T-cells to attack cancer.
• CAR-T cell therapy: Genetically engineered patient T-cells that recognise and destroy cancer cells, used for relapsed B-cell lymphomas, multiple myeloma, and ALL.
• Hormonal therapy: Oestrogen suppression (tamoxifen, aromatase inhibitors) for breast cancer; androgen deprivation therapy (ADT) for prostate cancer.
• Bone marrow and stem cell transplantation: High-dose chemotherapy followed by autologous or allogeneic stem cell rescue for haematological malignancies.
• Tumour biopsy and molecular profiling: Core needle or image-guided biopsies obtained to establish histological diagnosis and perform comprehensive genomic profiling.
• Implantable port-a-cath placement: Long-term venous access device inserted under the skin for repeated chemotherapy infusions.
• Palliative and supportive care: Pain management, anti-nausea medication, growth factor support, and symptom control integrated throughout the treatment course.

Oncology consultation is required in these situations:

• Confirmed cancer diagnosis: Any patient with a tissue-confirmed cancer diagnosis should be referred to a medical oncologist, radiation oncologist, or surgical oncologist depending on cancer type and stage.
• Suspicious biopsy or imaging: A pathology report showing malignant or pre-malignant cells, or imaging demonstrating a mass suspicious for cancer, warrants urgent oncology referral.
• Unexplained weight loss with constitutional symptoms: Greater than 10% unintentional weight loss over six months combined with fatigue, night sweats, or loss of appetite requires investigation for occult malignancy.
• Elevated tumour markers: Rising PSA (prostate), CA-125 (ovarian), CEA (colorectal), or AFP (liver) that is unexplained or persistently elevated requires oncology evaluation.
• Family history and genetic risk: Individuals with BRCA1/2, Lynch syndrome, or other hereditary cancer predisposition syndromes require risk assessment, surveillance planning, and potentially prophylactic interventions with an oncologist.
• Second opinion for cancer treatment decisions: Patients with rare cancers, complex multi-modality treatment plans, or uncertainty about chemotherapy regimen selection should seek a second opinion at a major cancer centre or seek clinical trial access.

Medical oncologists in the United States complete a four-year medical degree (MD or DO), a three-year internal medicine residency, and a two- to three-year fellowship in haematology and oncology (often combined). Fellowship training provides exposure to outpatient oncology clinics, inpatient haematology services, bone marrow transplant units, clinical trials, and tumour board conferences.

Radiation oncologists complete a separate four- to five-year radiation oncology residency after a one-year preliminary year, learning radiation physics, treatment planning, and clinical radiation delivery across all tumour sites. Surgical oncologists are trained as general or subspecialty surgeons who then complete an additional one- to two-year surgical oncology fellowship.

Board certification for medical oncologists is awarded by the American Board of Internal Medicine (ABIM) in Medical Oncology and/or Haematology. Radiation oncologists are certified by the American Board of Radiology (ABR). In the UK, oncologists hold MRCP or FRCR credentials. Continuing education, clinical trial participation, and multidisciplinary tumour board involvement are expected throughout an oncologist's career, given the rapid pace of therapeutic advances in cancer medicine.

Cancer care is ideally delivered at a dedicated cancer centre or hospital with a multidisciplinary tumour board for your specific cancer type. Tumour boards bring together medical oncologists, surgical oncologists, radiation oncologists, radiologists, pathologists, and palliative care specialists to collectively plan treatment for each individual patient.

For rare cancers or complex treatment decisions, seek referral to a National Cancer Institute (NCI)-designated comprehensive cancer centre or its international equivalent, which offer the broadest access to clinical trials and subspecialty oncology expertise. When attending your first oncology appointment, bring your pathology report, all biopsy material, recent imaging studies, and a list of all medications. Ask your oncologist about clinical trial eligibility and whether molecular tumour profiling (next-generation sequencing) has been completed to identify targetable mutations.