cancer

Definition cancer

cancer: cancer n. any *malignant tumour including *carcinoma and *sarcoma. It arises from the abnormal and uncontrolled division of cells that then invade and destroy the surrounding tissues. Spread of cancer cells (*metastasis) may occur via the bloodstream or the lymphatic channels or across body cavities such as the pleural and peritioneal spaces, thus setting up secondary tumours at sights distant from the original tumour. Each individual primary tumour has its own pattern of local behaviour and metastasis; for example, bone metastasis is very common in breast cancer but very rare in cancer of the ovary.

There are probably many causative factors, some of which are known, for example, cigarette smoking is associated with lung cancer, radiation with some bone sarcomas and leukaemia. Some tumours, such as retinoblastoma, are inherited. Treatment of cancer depends on the type of tumour, and the extent of spread.