Cancer is out-of-control cell growth, usually leading to tumors. The cancer is very serious if the tumor begins to spread (metastasize) throughout the body.
There are many different types of cancer. They are named based on where the tumor is located or where it first started growing. The most common forms of cancer are colon, lung, breast, and prostate.
Normally, the body makes new cells only when they are needed for growth or repair. This cell growth is controlled by a group of genes that work together. When one or more of these genes is damaged (mutated), cells can keep growing and dividing, leading to cancer.
Genes can be mutated by chemicals in the environment, like tobacco smoke. But more often, damage to growth-control genes occurs spontaneously in a single gene. That's why a tumor is typically found (or at least begins) in just one spot.
Most people who develop cancer have no family history of the disease, meaning their cancer was probably not inherited. But sometimes the more common cancers (e.g., breast, prostate, and colon) can run in families. If a close relative (grandparent, parent, or sibling) has been diagnosed with a common form of cancer, you too may be at risk. Your risk increases if the relative developed cancer at an early age (typically before age 50-55), or if more than one close relative developed the same cancer.
Fiber fights colon cancer, yet the average American consumes barely half of the recommended 20-35 grams of fiber per day.
The best ways to reduce cancer risk may differ slightly for each type of cancer. But here are some general guidelines to follow: