Tuesday, 20 September 2016

What is cancer ?

What is cancer?

Cancer is a class of diseases in which cells grow and divide uncontrollably. There are more than 200 different types of cancer. Each type is classified by the type of cell that is initially affected.  Cancer can start in the lungs, the breast, the colon, or even in the blood.
How cancer starts?In the normal case, cells grow and divide to form new cells in an orderly way, then they die, and new cells take their place when they grow old or become damaged. In case cancer develops, however, this orderly process breaks down. The cancer cells keep on growing and making new cells which are not needed. These extra cells can divide continuously and without stopping and may form growths called tumors. In some cases, cancer cells can also spread to other parts of the body through blood or lymphatic systems, destroying healthy tissue in a process called invasion. Metastasis is when a tumor successfully spreads to other parts of the body and grows, invading and destroying other healthy tissues. Tumors can be benign or malignant. Those that stay in one location and do not spread to other parts of the body are considered to be benign, they are not cancerous and are rarely life-threatening although they can sometimes cause problems, especially when their volume becomes too big.
Some cancers grow and spread fast. Others grow more slowly. Patients respond to treatment in different ways, but the most common treatments for cancer are surgery, chemotherapy, and radiation.Risk factors for cancerCancer is a genetic disease, it is caused by changes in genes inside the nucleus that control the way cells function, especially how they grow and divide, this means that cells become abnormal if their DNA is altered by certain environmental exposures. However, it is usually not possible to know exactly why one person develops cancer and another doesn’t., but research has shown that certain risk factors may increase a person’s chances of developing cancer. According to World Health Organization (WHO), common risk factors for cancer include:
-      Tobacco and alcohol
-      Insufficient fruit and vegetable intake
-      Physical inactivity
-      Chronic infections from helicobacter pylori, hepatitis B virus (HBV), hepatitis C virus (HCV) and some types of human papilloma virus (HPV) (Cervical cancer).
-      Environmental and occupational risks including ionizing and non-ionizing radiation
-      Chemical carcinogens (Several chemicals and environmental toxins are responsible for changes in normal cellular DNA).  

 

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