What is cancer disease?
Diseases in which cells divide abnormally without control and where other tissues invade is known as cancer. These cells spread through blood to other parts of the body. Cancer are not just one disease but many diseases because there are more than 100 different types of cancer. Cancer diseases are mostly named on the organ or type of cell where they occur. For example, cancer that begins in the colon is called colon cancer; cancer that begins in melanocytes of the skin is called melanoma.
Types of cancer-
Some of the cancer diseases are broadly discussed below:
1. Carcinoma – Cancer that occurs in the tissues that cover or near to internal organs is known as carcinoma. There are many subtypes of carcinoma, like den carcinoma, basal cell carcinoma, squamous cell carcinoma, and transitional cell carcinoma.
2. Sarcoma – cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
3. Leukaemia – cancer that starts in blood forming tissue such as the bone marrow. This causes large numbers of abnormal blood cells to enter the blood.
4. Lymphoma and myeloma – cancers that occur in the cells of the immune system.
5. Central nervous system cancers – cancers that occur in the tissues of the brain and spinal cord.
Origins of Cancer
All cancers first occur or begin from the cells. To understand cancer, it is important to know the changes that occur in the cells when they become cancer cells. The body is made up of many types of cells and these cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.
Sometimes this orderly process goes wrong and that is when a disease occurs in the body. In such, the genetic material or DNA gets damaged or changed leading to productions of mutations that affect the normal cell growth. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells form a mass of tissue called a tumour. Some cancers do not form tumours. For example, leukaemia is a cancer of the bone marrow and blood.
There are two main types of tumour-
1. Benign tumour-This type of tumour is not cancerous. It can often be removed, and in most cases it doesn’t return. Cells in benign tumours do not spread to other parts of the body. Thus they can be cured completely and not dangerous if notified and operated at the right time.
2. Malignant tumour-This type of tumour is cancerous. As cells in these tumours can invade into nearby tissues and can spread to other parts of the body. The spread of tumour from one part of the body to another part of the body causes cancer and in most cases cannot be cured. It can be cured but with no surety of returning back of the tumour.
