Cancer (General Overview)

Introduction: 

Cancer is a disease where one cell type within an organ has degenerated to the point where these cells have lost their ability to stop dividing. As these cells clone themselves, they invade first locally and eventually spread within the entire body through the blood vessels and the lymphatic system.

As they do this, clusters of new daughter tumors, called "metastases", are formed. These are colonies of the original tumor and their cells under the microscope look the same way as the original tumor. This is how the pathologist can diagnose cancer from a tumor cell sample. The cancer eventually invades vital organs such as the liver, the lungs, the bone marrow, brain, the kidneys or the adrenal glands. This destroys the healthy tissue and changes the metabolism leading to nausea, weight loss and weakness. This state of weakness worsens and leads to death as a result of liver failure, lung failure, bone marrow failure or cerebral edema (in the case of brain metastases).

Not every cancer is equally common. There are some cancers that are rare such as liver cancer or testicular cancer (see table below). Other cancers are very common such as lung cancer, prostate cancer or breast cancer. To keep statistics on this over the decades, cancer clinics and cancer control agencies compile average annual rates of new cancers to see whether there is a trend with rates going up or down.

Disclaimer: 

This outline is only a teaching aid to patients and should stimulate you to ask the right questions when seeing your doctor. However, the responsibility of treatment stays in the hands of your doctor and you.

References:

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