While there are many different types of cancer, all cancer occurs when a person’s cells stop behaving normally and begin to grow abnormally. Normal cells grow, divide and die, but cancer cells reproduce faster than they die because of a problem in the cells’ genes that tells the affected cells to multiply uncontrollably or allows them to live too long.
In most types of cancers, this rapidly multiplying group of cells forms what is called the primary tumor.
Other types of cancers, such as leukemia, do not cause tumors but impact the blood instead.
How Cancer Affects the Body
Cancer can cause problems in several ways:
1. The primary tumor can grow and affect the organ where it started ability to function.
Example: A colon cancer that causes an intestinal blockage.
2. A primary tumor can also grow into an organ next to where it started.
Example: A cancer that starts in the lung, but affects the heart or blood vessels in the chest.
3. Cancer can also cause problems when cells from the primary tumor learn how to break off and get into the blood stream. They then can get stuck in an organ or lymph node far away from where they started. Once there, they can grow and cause problems in that organ’s ability to function, much like the primary tumor.
Example: Lung cancer that spreads to the brain, causing a headache that originates from the spot in the brain, not the primary tumor in the lung.
Stages of Cancer
Before beginning treatment, your doctor needs to find out how much cancer there is in your body and how far it has spread. Making this determination is called staging – evaluating the status of the cancer.
For tumors of internal organs, also called solid tumors (such as lung, breast and colon cancers), there are four stages of cancer. In general, the lower the number, the less the cancer has spread. A higher number, such as stage IV (4), means the cancer has spread further and is more serious.
Stage I and Stage II tumors are usually small and have not yet had a chance to spread from the organ where they started. What typically separates Stage I from Stage II tumors is the tumor’s size or exactly how far the primary tumor has grown.
Stage III tumors have either spread to the lymph nodes, or the primary tumor has grown in such a way that it is not safe to operate on it. For example, if a lung cancer is too close to the heart, an operation is not a safe treatment option.
Stage IV cancer is advanced and generally not considered curable. Therefore, the goal of treatment in this situation is to shrink the tumor and keep it in check for as long as possible. By shrinking the tumor, symptoms of cancer can be alleviated and quality of life improved.
For cancers of the blood stream or immune system (leukemia, lymphoma, etc.) staging is a bit more complicated.