Cancer

This article is written to help you understand more about cancer. It is not the same as getting advice from your doctor.

If you have signs of cancer, you should talk to your doctor immediately – now!

The World Health Organization lists 7 warning signs of cancer. Please refer to the table below.

Sometimes these signs are caused by other illnesses but it is important you go see your doctor have them checked.

What is Cancer?

Your body is composed of trillions of cells. A cell is the smallest structural and functional unit of your body. Together, they provide structure for the body, digest and utilize nutrients from food, process those nutrients into energy, and perform specific functions.

Cell division (cell re-creation) is going on right now in your body. It is essential for three major functions:

1. Growth
2. Development
3. Repair and maintenance

By way of cell division, a single cell becomes two cells. Those two cells divide into four, and the four cells divide into eight, and so on.

Cell division is a controlled or regulated biological process. When this process goes out of control, cells rapidly divide. This group of abnormal, rapidly dividing cells turns into a lump called a tumor. See figure below.

There are two types of tumors:

• Benign
• Malignant (cancerous)

A benign tumor is an abnormal growth that does not invade nearby tissue (a group of the same cells) or spread to other parts of the body the way a malignant tumor can – they only grow in one place.

Most of the time, benign tumors have a very good outlook. However, if it presses on vital structures, like a blood vessel or a nerve, it can produce a serious condition.

Malignant or cancerous cells divide rapidly and can easily invade other tissues by growing into them. They can also use the bloodstream or the lymphatic system as transportation to invade or spread (metastasize) to other distant tissues. Metastasis is the development of secondary malignant growths away from the main site of cancer.

Types of Cancer

There are hundreds of different types of cancer, but cancers in general, belong to five basic categories:

• Carcinomas
• Sarcomas
• Myelomas
• Lymphomas
• Leukemias

Carcinomas are the most common cancers. They originate in tissues which either cover surfaces or line internal organs, accounting for 80 to 90 percent of malignant cases. There are two major subtypes of carcinoma:

• Adenocarcinoma – develops in an organ or gland.
• Squamous cell carcinoma – originates in the epithelium (surface layer of cells), usually the skin.

Examples of carcinomas include cancers of the breast (see figure below, Mammary ductal carcinoma), prostate, lung, intestine, skin (see figure below, squamous-cell carcinoma), pancreas, liver, kidneys, and bladder.

Sarcomas are malignancies originating in connective tissue developing in bones, muscles, fat, cartilage, nerves, tendons, and joints, usually in the arms or legs. Sarcomas are the rarest and most deadly forms of cancer.

Myelomas are also rare forms of cancer and originate in the plasma cells of the bone marrow (soft tissue inside the bones). Plasma cells are immune cells responsible for fighting infection by producing antibodies. Myeloma cells hinder normal antibody production, weakening the immune system.

The increased rate of myeloma cell division additionally interferes with normal production and function of red and white cells and can result in bone destruction, leading to bone pain and/or fractures. Since myeloma often develops at many sites in the bone marrow, it is often called multiple myeloma.

Lymphomas are cancers that develop from lymphatic cells (a vital part of the immune system). The two most common types are Hodgkin disease and Non-Hodgkin lymphoma. The second group includes Common B-cell lymphoma and the rarer T-cell lymphoma. Non-Hodgkin lymphoma is also classified as indolent or aggressive, based on how fast they are growing.

Leukemias are cancers of the blood. The malignant cells begin to form in the bone marrow, the soft tissue inside nearly all of the bones. Bone marrow contains the cells that give rise to the following blood cells:

• White blood cells (WBC) – enable your body to fight infection.
• Red blood cells (RBC) – transport oxygen to all parts of the body.
• Platelets – are important cells for blood clotting.

Once an individual has leukemia, his bone marrow starts to produce a great number of abnormal (malignant) WBCs, called leukemic cells. These cells don’t function like normal WBCs. They grow faster and don’t stop growing when they should.

With time, leukemic cells can crowd out the normal blood cells (see figure below). This can give rise to serious problems like anemia, bleeding, and infections. Leukemia cells can also metastasize to the lymph nodes or other organs and can result in swelling or pain.

There are many types of leukemia. Generally, leukemia is identified by how rapidly it gets worse and what type of white blood cells are affected.

It can be acute or chronic. Acute leukemia gets worse very fast and symptoms appear quickly. Chronic leukemia gets worse gradually and will possibly not cause symptoms for years.

It could be lymphocytic or myelogenous. Lymphocytic leukemia involves white blood cells called lymphocytes. Myelogenous leukemia involves the other type of cells that give rise to granulocytes, red blood cells, or platelets.