What is cancer?
Our body is made up of many types of cells. These cells divide and grow in a controlled manner as the body needs them. But many times it happens that the body has no need of these cells, yet they continue to grow. This abnormal growth of cells is called cancer (which usually arises from an abnormal cell) in which the cells lose normal control. Thus a group of cells continuously grow uncontrollably, invading surrounding adjoining tissues, which reach into distant parts of the body and spread to other parts of the body through lymph or blood. Cancer cells can develop in any tissue of the body.
As cancer cells grow and multiply, they form a group of cancer cells called tumors. This tumor attacks the surrounding tissue and destroys them. Tumors can be cancerous or non-cancerous. Cancerous cells can start from one place and spread throughout the body (metastases).
How would it happen and spread
Cancer cells develop from healthy cells in a complex process called malignant transformation.
How does it start –
Cancer begins due to changes in the genetic material of the cell. Changes in the genetic material of the cell can happen on their own or can be caused by some agent or element. These agents are chemicals, tobacco, viruses, radiation and sunlight. But not all cells are equally affected by these agents. A genetic defect in the cells makes these agents susceptible to the body. Even prolonged physical irritation can make these agents susceptible to a cell.
How does it grow –
Some agents or elements (promoters) cause to promote the development of cancer. These agents may also be some substances or drugs present in the environment such as the sex hormone testosterone which is used to improve sexual desire and energy in older men. Unlike carcinogens, these promoters do not by themselves cause cancer. Instead, these promoters promote the growth of cells affected by cancer. These promoters have no effect on cells in which the cancer has not started.
Some cancer-causing elements cause cancer without the need for promoters. For example, (ionizing radiation – mostly used in X-rays) can cause various cancers, especially sarcoma, leukemia, thyroid cancer, and breast cancer.
How does it spread?
The cancer can grow directly in the surrounding tissue or spread to the organs, whether they are distant or near. Cancer can spread through the lymphatic system. This type of spread also occurs in carcinoma. For example, breast cancer usually spreads to the nearest lymph nodes in the armpits and later it spreads to other parts of the body. Cancer can also spread through the bloodstream. This type of spread also occurs in sarcoma cancer.
Stage of cancer –
Cancerous tissues can be divided into blood and blood-forming tissues (leukemia and lymphomas) and “solid” tumors (solid mass of cells), often referred to as cancer. Cancer can be carcinoma or sarcoma.
Leukemia and lymphoma are blood cancers. Leukemia arises from blood-forming cells in which immature white blood cells with high levels in the bone marrow and bloodstream, displaced normal blood cells. In lymphoma, cancer cells expand the lymph nodes. Lymphoma often starts at the lymph nodes but can also be found in the armpit, genitalia, stomach, chest or intestine etc.
Carcinoma is the most common type of cancer. In which cancer cells affect the internal and external parts of the body such as lung, breast and stomach cancer. It starts with the epithelium tissue of the skin. Examples of carcinoma are skin, lung, colon, stomach, breast, prostate, and thyroid gland cancers. Typically, carcinomas are more common to older people than younger ones.
Sarcoma is a tumor that occurs in interconnected tissues. Common connective tissues include fat, blood vessels, nerves, bones, muscles, cartilage, etc. Examples of sarcoma are – leiomyosarcoma and osteosarcoma (bone cancer). Generally, this cancer occurs more in younger people than older people.