Cancer is defined in most dictionaries is “the spreading of any evil.” Cancer is a definite evil, a disease of uncontrolled cell growth. It is a major health problem in our society and is second only to heart disease as a cause of death in the United States. More than one million people develop cancer each year.
The Development of Cancer
Our bodies go through a process of normal cell growth in which cells divide when new cells are required. Normally cells stop dividing when this need is met. Tumors are caused when our body is not signaling the end of cell division properly.
The changes in cell behavior may be due to genetic material in our cells. A tumor suppressor gene is supposed to stop abnormal division of the cells but if this gene is lost or is damaged a tumor can develop. If a proto-oncogene is activated it can lead to changes that cause our body cells to lose control of what happens when they divide.
The characteristics of cancerous tumors are uncontrolled cell growth, damage to healthy tissues, and the ability to metastasize, or spread.
Both benign and malignant tumors are abnormal. A benign tumor is encased in a membrane that keeps it from getting to other body tissues. Benign tumors are not considered to be cancerous but can cause damage to healthy tissues when the mass is large enough to compress them. A malignant tumor is much more dangerous and harmful than a benign tumor. A malignant tumor is cancerous because the cells are not encased in a membrane and can invade and destroy nearby tissues.
Cancerous cells can travel throughout the body via the circulatory system or the lymphatic system causing secondary cancers. The cancer is said to metastasize when this happens. The secondary cancers are also known as metastases.
Different Types of Cancer
The human body is composed of many different types of cells. Because of this many different types of cancers can develop such as carcinoma, sarcoma, leukemia, and lymphoma.
Carcinoma is a type of epithelial cancer that develops in the skin, in the glandular tissue (breast or prostate), or in the linings of bodily parts or organs (mouth or stomach). Sarcoma is a type of cancer that originates in the connective tissues (tendons), bone, or muscle. These two terms are often combined with other words that help to specify an organ or cell type in which the cancer originated. For example, an osteosarcoma is a cancer that originated in the bone.
Leukemia is cancer that is located in the bone marrow. Bone marrow consists of red blood cells, white blood cells that fight infection, and cells that prevent uncontrolled bleeding, or platelets.
Cancers that originate in the lymph nodes are known as lymphomas.
Causes of Cancer
Many different factors can be identified as contributing to cancer development. Among these factors are hormonal imbalances, genetic abnormalities, some viral infections, nutritional disorders, and immune system disorders. If genetic abnormalities are inherited from another family member there could be a high risk for a particular type of cancer.
Carcinogens, or cancer causing substances, can transform a healthy cell into a cancerous one. Substances such as tobacco and tobacco smoke contain many different carcinogens that can interact with each other causing a higher risk of cancer. Chemicals such as asbestos fibers, benzene, and radiation are known to cause cancer.
Diagnosing Cancer
Mammograms and blood stool tests are two examples of early detection tests. These types of tests can be performed before noticeable symptoms of cancer ever appear. Tests such as these have reduced the incidences of certain types of cancer and have increased the chances of people being cured.
When a tumor is located, a piece of it is removed from the patient and examined under a microscope to determine if it is benign or malignant. This test is called a biopsy and helps to determine the prognosis. A prognosis is a predicted course for treatment of a disease.
A staging, or further evaluation, is used to determine the extent to which the cancer has spread and the best way in which to treat it.
Treatment of Cancer
Before the 1900’s very few people survived cancer but with today’s technology and early detection tests more than half of the cancer victims survive the disease. People who have been treated and are free of cancer for five years or more are considered cured.
Three standard methods that are used in the treatment of cancer are surgery, radiation therapy (radiotherapy), and chemotherapy (drug therapy). Sometimes a combination of two or more treatments is used.
Most cancer treatment methods cause undesirable side effects such as scarring or loss of an organ or body part due to surgery, hair loss or skin irritation due to radiation, or nausea or fatigue due to chemotherapy. Side effects are dependent on the individual and the type of treatment used. Most side effects disappear once treatment is completed.