The word 'cancer' describes a group of more than 200 diseases caused by uncontrolled cell division. The genes of normal cells change so that regular cell death does not take place, and the tissues grow much larger than normal. Some factors, such as tobacco use and excessive exposure to different types of radiation, can notably increase the chances of developing cancer. In other cases, the genes that alter the normal functions of cells can be inherited.

How it Behaves

In general, cancer consists of the abnormal growth of cells. When the cells of a tissue undergo disorderly and accelerated cell division, they can invade other, healthy tissues in the body and often destroy them. Instead of undergoing a controlled and programmed cell death, cancer cells continue proliferating. They can form a lump or bulge in an organ, called a tumour. Tumours are termed malignant if they are formed by cancer cells; otherwise they are called benign .

Common Symptoms

Although they are not always indicators of cancer, unusual bleeding, unexplained changes in weight, indigestion and difficulty swallowing can be signs of tumours.

The most common cancer is lung cancer. Because of the large smoking population, the incidence of this cancer remains high. In recent years, the frequency of lung cancer in women has increased, and it is possible that cases of lung cancer in women might surpass those of breast cancer, currently the most common type of cancer in women. In men, prostate cancer becomes more common as age increases.

Metastasis

Metastasis occurs when cancer cells pass from their original proliferation site to another that they were not in direct contact with. To achieve this migration, the cells build their own circulatory and feeding systems. This allows them to penetrate the blood vessels and survive after extravasation. Only one in every 1,000 cells can survive the complex intermediate processes, but if metastasis does occur, it is almost irreversible and causes irreparable damage.

TUMOURS

These are produced when the cancer cells and form agglomerates. Tumours can be benign (non - cancerous) or malignant.

Breast Cancer

One in nine women develops this disease, which causes the most deaths among women. The risk of breast cancer increases with age. The most common symptom is the appearance of a small lump in the breast, which can be removed early with surgery. Other symptoms of cancer are the appearance of blood in the nipple and dimples in the breast skin. A mammogram is usually used to detect cancer. If the results of this study are positive, then treatment can begin early.