Oncology Health Dictionary

The study of the causes, development, characteristics, and treatment of tumours, particularly cancers.

The management of MALIGNANT disease – a major health problem since successful management requires close liaison between the patient, surgeons, physicians, oncologists, haematologists, paediatricians and other specialists. Diagnosis may involve various investigations and often requires a BIOPSY. Once a diagnosis has been established, treatment may involve surgery, radiotherapy or chemotherapy (or various combinations as required) – see below, and main dictionary entries.

Surgery may be most common, and is often the only treatment, for some gastrointestinal tumours, soft-tissue tumours, gynaecological tumours and advanced cancers of the head and neck.

Radiotherapy uses ionising radiation to kill tumour cells. Radiation is by naturally occurring isotopes (see ISOTOPE) or arti?cially produced X-RAYS. Germ-cell tumours (see SEMINOMA; TERATOMA) and malignant lymphomas (see LYMPHOMA) appear to be particularly sensitive to irradiation, and many head and neck tumours, gynaecological cancers, and localised cancers of the PROSTATE GLAND and URINARY BLADDER are curable with radiotherapy. It is also a valuable means of reducing pain from bone metastases (see METASTASIS). Unpleasant side-effects are common: chie?y lethargy, loss of appetite and dry, itchy skin symptoms.

Chemotherapy is also an important treatment in germ-cell tumours (see above); in some forms of LEUKAEMIA and lymphoma; in ovarian cancer (following surgery – see OVARIES, DISEASES OF); and in small-cell lung cancer (although most patients die within 18 months – see LUNGS, DISEASES OF). It is also used in some breast cancers (see BREASTS, DISEASES OF); advanced myeloma (see MYELOMATOSIS); sarcomas (see under CANCER); and some childhood cancers (such as WILMS’ TUMOUR).

More than 20 substances are in common use, the major classes being ALKYLATING AGENTS (e.g. cyclophosphamide, chlorambucil, busul fan); ANTIMETABOLITES (e.g. methotrexate); VINCA ALKALOIDS (e.g. vincristine, vinblastine); and antitumour ANTIBIOTICS (e.g. actinomycin D). Choice of agent and the appropriate regimen requires expert guidance. Common side-effects include nausea and vomiting, bone-marrow suppression and ALOPECIA, with each substance having its own spectrum of unwanted effects.

Good doctor-patient communication, with the sharing of information and bringing the patient into the decision-making process, is vital even if time-consuming and exhausting.

Equally imortant treatment is PALLIATIVE, for example to ensure e?ective pain or nausea control. Common sources of pain in cancer may involve bone, nerve compression, soft tissue, visceral, myofascial, constipation, muscle spasm, low-back pain, joint pain (e.g. capsulitis) and chronic post-operative pain. Patients may be suffering from more than one pain, all of which should be identi?ed. The aim should be to eliminate pain.

There are three rungs of the analgesic ladder; if one rung fails, the next one should be tried:

(1) non-opioid drugs – for example, aspirin, PARACETAMOL, NON-STEROIDAL ANTIINFLAMMATORY DRUGS (NSAIDS); (2) weak opioids – for example, CODEINE, DIHYDROCODEINE, dextropropoxyphene; (3) strong opioids

– for example, MORPHINE, DIAMORPHINE, buprenorphine. Oral treatment is always preferable, unless prevented by severe vomiting. (See also CANCER; ONCOLOGIST; PAIN; PALLIATIVE CARE.)

The study of cancer.

n. the study and practice of treating tumours. It is often subdivided into medical, surgical, clinical, and radiation oncology. —oncologist n.