General Questions

How did I get cancer?

Although every patient and family member wants to know the answer to this question, the reason people develop cancer is not well understood. There are some known carcinogens (materials that can cause cancer), but many are still undiscovered. We do not know why some people who are exposed to carcinogens get cancer and others do not. The length and amount of exposure are believed to affect the chances of developing a disease. For example, as exposure to cigarette smoking increases, the chance of developing lung cancer also increases. Genetics also plays an important role in whether an individual develops cancer. For example, certain types of breast cancer have a genetic component.

Are all cancers the same?

No two cancers are exactly the same, even when they are cancers of the same organ. The differences have to do with what is called the "biology" of the disease. While there are general ways in which cancers are similar, it means that each cancer has its own characteristics that make each person react differently to the cancer and its treatment. Cancer is a change in cells that lets the cells divide into new cells without any control. As new cells are produced, a tumor is formed. In cancers, the cells can break free of the tumor or group of cancer cells and travel through the blood or lymph system (the infection fighting system) to other parts of the body.

Do cancers come from something inside or outside the body?

Cancer is a disease that is caused by the body's own cells. Our cells have special control signals in them that are supposed to limit the size of cells and the number of new cells. These controls limit cells to just what the body needs. In cancer cells, the control signals are lost and the cells grow when they should not. No one knows why these controls fail, but it is not a problem that can be "caught" like a cold or other infection.

There are some cancers that have been linked to things in the environment. Even though it still is not known exactly how these conditions cause the cancer to start, the association is strong enough to warn people to avoid them.

Some examples will help in understanding this:

UV radiation in sunlight causes changes in skin cells that can lead to melanoma, a serious skin cancer.
Sun exposure is also linked to two other cancers, squamous cell carcinoma of the skin and basal cell carcinoma.
Knowing about this link between sun exposure and skin cancers has lead to the widespread use of sunblock lotions.