|
Cancer is a general term for a number of diseases which arises
due to uncontrolled growth of abnormal cells in different parts of the body.
Under normal circumsCtances, the number and growth of all our cells is a highly
controlled mechanism. Sometimes DNA molecules inside a normal cell is attacked
by carcinogens causing irreversible damage to its life cycle, leading to number
of chain reactions to produce a cancer cell. The cancer cell multiplies uncontrollably
and the result is an accumulation of abnormal cells called a tumor, or lump.
Cancers may be caused by genetic factors, diet, tobacco, sun, radiation, lack
of vitamin A, excessive oestrogen, Carcinogenic chemicals such as arsenic etc.
The resulting tumor can be either benign or malignant. A benign
tumor does not spread, or metastasize, to other parts of the body, is non-cancerous,
and is rarely life-threatening. Many breast lumps, for example, are benign tumors.
A malignant tumor, however, can spread and is cancerous. When this tumor spreads,
its malignant cells break off and travel through the blood lymph system to other
places in the body to settle and multiply, or metastasize, resulting in other
tumors called a secondary tumor, or metastasis.
Cancers exist in many different forms. They are classified according
to the cells that give rise to them, to the organ of its origin as well the
appearance of the cancer cells. Carcinoma, adenocarcinoma, sarcoma, melanoma,
leukemia etc are broad classes of cancer cell types. Sarcomas are cancers of
the connective tissue, cartilage, bone, muscle, and so on. Carcinomas are cancers
of epithelial (lining) cells. Adenocarcinoma refers to carcinoma derived from
cells of glandular origin. Several Cancers of different cell types can occur
in the same organ. For example kidney cancer can be of different types based
on different cells such as renal cell cancer, transitional cell cancer, Wilm's
tumour etc.
A Cancer can develop slowly over several years while the
person show no symptoms at all. Once symptoms are seen it may vary according
to the specific type of cancer you have. Common symptoms can be a lump or thickening
in the breast or testicles, a change in a wart or mole, a skin sore or a persistent
sore throat that doesn't heal, a change in bowel or bladder habits, a persistent
cough or coughing blood, constant indigestion or trouble swallowing, unusual
bleeding or vaginal discharge, chronic fatigue etc. Many cancers are curable
if detected at an early stage. |
