The body is made up of many types of cells. Normally, cells grow, divide and die. Sometimes, cells mutate (change) and begin to grow and divide more quickly than normal cells. Rather than dying, these abnormal cells clump together to form tumors. If these tumors are cancerous (also called "malignant"), they can invade and kill your body's healthy tissues. From these tumors, cancer cells can metastasize (spread) and form new tumors in other parts of the body. By contrast, noncancerous tumors (also called "benign") do not spread to other parts of the body.
There are many different types of cancer, but all cancers begin with abnormal cells growing out of control. The type of cancer is determined by where the growth of abnormal cells begins. The most common cancers in adults are skin cancer, lung cancer, colon cancer, rectal cancer, breast cancer, endometrial cancer, ovarian cancer and prostate cancer.
Skin cancer is the most common form of cancer. Fortunately, it is also the most curable. There are 2 forms of skin cancer: melanoma (the less common but more serious form) and nonmelanoma (the common, very treatable form). More than 1 million people will be diagnosed with skin cancer this year. Most will have nonmelanoma skin cancer. Almost all skin cancers are the result of too much exposure to ultraviolet light, which is in sunlight and in lights used in tanning salons.
It's important to find skin cancer as early as possible. The best way to do this is to keep an eye on your skin, especially moles. The ABCDE rule (see below) can help you remember what to look for when you're checking any moles on your skin. If you notice any of these signs, talk to your doctor right away.
A for asymmetry: A mole that, when divided in half, doesn't look the same on both sides.
B for border: A mole with edges that are blurry or jagged.
C for color: Changes in the color of a mole, including darkening, spread of color, loss of color, or the appearance of multiple colors such as blue, red, white, pink, purple or gray.
D for diameter: A mole larger than 1/4 inch in diameter.
E for elevation: A mole that is raised above the skin and has an uneven surface.
There are 2 major forms of lung cancer: non-small cell and small cell. Non-small cell lung cancer is more common than small cell lung cancer, and it generally grows and spreads more slowly. Small cell lung cancer is almost always caused by smoking. In fact, cigarette smoking is the single most important risk factor for developing lung cancer. If you smoke, talk to your doctor about quitting. He or she can help you figure out how to kick the habit.
Colon cancer begins in the large intestine (called the colon). Rectal cancer begins in the rectum, the part of the large intestine closest to the anus (the outside opening to the intestine). These forms of cancer have many common features. Sometimes they are referred to together as colorectal cancer.
Most colorectal cancers begin as a polyp (say "pahl-ip") At first, a polyp is a small, harmless growth in the wall of the colon. However, as a polyp gets larger, it can develop into a cancer that grows and spreads.Warning signs of colorectal cancer may include blood in your stool or in the toilet after you have a bowel movement, a change in the shape of your stool or cramping pain in your lower stomach. You should see your doctor if you have any of the warning signs of colorectal cancer.
Breast cancer begins in breast tissue. Most of the tumors that develop in breast tissue are benign. Some breast tumors are cancerous, but have not yet spread to other parts of the body. This type of breast cancer is called "in situ," and it can almost always be cured with treatment. The most serious type of breast cancer is invasive, meaning that the cancerous tumors have spread to other parts of the body.
Breast cancer is the second most common cancer among women (behind skin cancer). The good news is that the rate of death from breast cancer has declined over the last few years. This is probably because more tumors have been found early, when treatment can help the most. Mammograms and breast exams (both self-exams and exams by a doctor) can help find breast cancers early.
Cancer of the lining of the uterus (womb) is called endometrial cancer. It is most common in women who have gone through menopause. The most common early sign of endometrial cancer is unusual bleeding from the vagina (sometimes called "spotting"), especially bleeding that happens after menopause.
Ovarian cancer is cancer on one or both of the ovaries. The ovaries produce eggs, and the female hormones estrogen and progesterone. There are several types of tumors that can grow in or on the ovaries. The type of tumor depends on where it began growing and whether or not it is cancerous. Unfortunately, ovarian cancer is very hard to detect at an early stage. Your doctor may check your ovaries during your routine pelvic exam to see if they feel normal, but many times the tumors are so small they can't be detected.
A Pap smear is usually not able to find endometrial or ovarian cancer. The Pap smear checks for cervical cancer, which is less common than either endometrial or ovarian cancer. Cervical cancer was once more common, but early detection of cervical changes with the Pap smear has had a big impact.
Prostate cancer begins in the prostate gland in men.The prostate gland is located just below the bladder and in front of the rectum. It makes a fluid that mixes with sperm and other fluids during ejaculation.
Prostate cancer can grow quickly and spread to other parts of the body, or it can grow slowly and stay in the prostate. Three out of 4 cases of prostate cancer are the slow-growing type that causes few, if any, problems.