Cancer

Alternate Names : Carcinoma, Tumor, Malignancy

A cancer is a group of abnormal cells, known as a tumor, that grows uncontrollably. Cancerous tumors invade and destroy surrounding tissue. Not all tumors are cancerous. Benign tumors, which are not cancerous, do not invade and destroy tissue. However, a benign tumor may grow very large. Cancerous tumors may shed cancer cells that spread to other parts of the body. This is called a metastasis. Benign tumors do not spread in this way.

What is going on in the body?

A chromosome is genetic material within the nucleus of a cell. Chromosomes provide the so-called blueprints that direct normal cell function. The nucleus that houses the chromosomes is the control center for the cell. The nucleus of a normal cell, such as a muscle cell, controls its activity as part of a larger tissue, a muscle. The cell will then act in concert with other cells of that muscle to expand and contract, causing motion. Damage to the nucleus prevents the cell from behaving normally.

Cancer occurs when the damage causes changes that make the cell grow and divide wildly. When a cell becomes cancerous, over time a tumor forms from these abnormal cells. Because the tumor is made up of defective cells, it cannot function as it should. The body suffers in two ways:

A cancer is named by the type of organ tissue from which it developed. For example, breast cancer will always be called breast cancer, even if it spreads to other body parts. The type of tissue within an organ that underwent the cancerous change also further identifies a cancer. For example, lung cancer is grouped into several groups depending on exactly what kind of lung tissue was affected. A cancerous tumor does not grow any faster than the kind of tissue from which it started. But it does keep growing and multiplying uncontrollably. Healthy tissue does not grow constantly.

In the early stages of any cancer, you may not be able to see much of an effect on the body. But cancer cells can break off from the main tumor and travel through your blood stream to other parts of your body. These cancer cells may then form new tumors, known as metastases. As the cancer grows and spreads, or metastasizes, the person will likely begin to weaken. Cancer makes it hard for your body to function normally.

In the advanced stages of cancer, symptoms such as weight loss, weakness, and fatigue are common. At the same time, new cancerous tumors that spread to other parts of the body may cause other organs to fail. If not successfully treated, the cancer will destroy the functioning of vital body systems. This can lead to death.

These vital body functions include:

Most cancers occur in people older than age 55. This may be because cells become more vulnerable to damage after years of use. It is possible for children to have cancer, but this is rare. More men than women have cancer. The most common cause of cancer death in men and women is lung cancer.

What are the causes and risks of the disease?

For cancer to occur, something must damage the nucleus of the cell. Some people are born with a tendency for cancer. Their cells may be more vulnerable to the kind of damage that leads to cancer. For others, the damage occurs after years of exposure to substances that can cause cancer. Tobacco from any source is very dangerous. Certain chemicals, unprotected sun exposure, and radiation can all cause serious damage.