Cancer is the second leading cause of death (after heart disease) in the United States today, and the incidence of cancer is rising. There are two major factors leading to the increase in cancer. The first is increasing pollution. Many pollutants are toxic and cause cellular mutations, which can lead to cancer. The second factor is the increasing age of our population. The risk of cancer goes up with age. Because people are living longer than they used to, there are now more older people in our society, and those older people are at higher risk for getting cancer.
Definition: The word "cancer" refers to a mass of living tissue that is growing at a rate which is faster than the rate of its surrounding tissues. A cancer mass consists of altered cells that grow faster than normal, and do not respond to the normal signals that tell cells to slow down or stop growing. Because the cells are growing out of control, the mass continually gets larger, crowding out and putting pressure on surrounding tissues and organs. This pressure can cause pain and loss of function in those surrounding tissues.
Cells: To understand how cancer forms, we must look at how a normal cell functions. In the picture below, the cell on the left represents a typical cell in the human digestive tract. It is very specialized. It has finger-like projections on its surface to help it absorb digested nutrients. It has special proteins at its bottom that anchor it to a basement membrane. Its nucleus is located in the lower half of the cell, and a dense band of protein fibers is seen at the bottom of the cell, connecting to the anchor proteins. A doctor or biologist could quickly and easily recognize it as a digestive cell, and not a bone cell or muscle cell. This is what is meant by "specialized".
Genes: The function of a cell's genes or DNA is to produce proteins that the cell can use. Each gene in the cell produces one type of protein. If one gene in the cell becomes damaged and undergoes a mutation, then that gene may produce an altered protein or no protein at all. When one protein in a cell is altered, the structure and function of the cell may be slightly altered, but the cell can usually function normally nonetheless, much like the way a car with a dent in its side can still function. As time goes by, that cell will probably stay the way it is, but there is a chance that it could encounter a second mutation.
Cancer cells: If the dysplastic cell unfortunately sustains additional mutations, particularly if one of the mutations affects a protein that regulates cell growth, then the cell may progress into a cancer cell. In the figure, the cell on the right represents a cancer cell. As you can see, the cell is even less specialized, and functions even less, or not at all. It is barely attached to the basement membrane. It is growing in size, and soon it will divide in half, forming two identical daughter cancer cells. The new cancer cells may form a mass that continues to grow and divide, eventually crowding out the surrounding normal cells. Without adequate treatment, the amount of normal tissue left may not be enough to sustain life. Fortunately, treatment is available.
Prevention: Knowing what we know about how cancer forms, what can we do to prevent it? There are two effective strategies. First, we need to minimize the number of mutations that our cells sustain. We can do this by avoiding known toxins, such as industrial pollution, smoke from automobile exhaust and industry, excessive alcohol, radiation, and the biggest toxin of all, cigarette smoke. Second, we need to look for dysplasia, and remove it, so that it cannot progress into cancer. These two strategies are very effective, and most people who follow current recommendations do not need to worry about cancer. (Most people who get cancer today are people who smoke or have not followed the other preventative recommendations.)
Immune Function: How can we find and remove dysplasia? Well, the best tool is a healthy immune system. The average person will develop a small tumor on occasion throughout life. A healthy immune system will usually recognize and kill the abnormal cells before the person even notices them. Those who have weakened immune systems are at increased risk for cancer, as well as infections. The immune system can be weakened by stress, depression, smoking, poor nutrition, uncontrolled diabetes, certain other medical conditions, and old age. Thus, we can lower our risk of cancer (and infections) by lowering stress, treating depression and other medical conditions, avoiding cigarettes, eating fruits and vegetables, and taking one multivitamin pill per day. Also, regular exercise has been shown to lower the risk of cancer.
Screening Tests: The other way to find and remove dysplasia is through preventative medical care with your doctor. There are certain organs in the body which are at higher risk for dysplasia and cancer, and doctors have developed tests that specifically look at these high risk organs for signs of dysplasia or cancer. These tests include the following.
All of the above tests are important for monitoring high risk organs, removing dysplasia, and preventing cancer. All the high risk organs are screened by these tests except for the Lungs, for which there is no recommended screening test. The way to avoid Lung Cancer is by avoiding smoking. Anyone who has had cancer, either themselves or in their family, needs to start screening tests early.
Treatment: If you think you may have cancer, you should see your doctor. Good treatments are available, and they are most effective when started early. Many people are cured of cancer. The likelihood of cure depends upon the specific type of cancer and how early it is treated. If you have been diagnosed with cancer, I recommend the book and/or videotape by David Bognar (and Walter Cronkite) entitled Cancer: Increasing Your Odds for Survival. The book is pictured on the right. I hope this information has helped you to understand what cancer is and how to think about it and deal with it.