Cancer Overview
What is Cancer?
Throughout our lives, healthy cells in our bodies divide and replace themselves in a controlled fashion. Cancer starts when a cell is somehow altered so that it multiplies out of control. A tumor is a mass composed of a cluster of such abnormal cells.
Most cancers form tumors, but not all tumors are cancerous.
Benign, or noncancerous, tumors — such as freckles and moles — stop growing, do not spread to other parts of the body, and do not create new tumors. Malignant, or cancerous, tumors crowd out healthy cells, interfere with body functions, and draw nutrients from body tissues.
Cancers continue to grow and spread by direct extension or through a process called metastasis, whereby the malignant cells travel through the lymphatic or blood vessels — eventually forming new tumors in other parts of the body.
The term “cancer” encompasses more than 100 diseases affecting nearly every part of the body, and all are potentially life-threatening.
The major types of cancer are carcinoma, sarcoma, melanoma, lymphoma, and leukemia. Carcinomas — the most commonly diagnosed cancers — originate in the skin, lungs, breasts, pancreas, and other organs and glands. Lymphomas are cancers of lymphocytes. Leukemia is cancerof the blood. It does not usually form solid tumors. Sarcomas arise in bone, muscle, fat, or cartilage and are relatively uncommon. Melanomas are cancers that arise in the cells that make the pigment in skin.
Cancer has been recognized for thousands of years as a human ailment, yet only in the past century has medical science understood what cancer really is and how it progresses. Cancer specialists, called oncologists, have made remarkable advances in cancer diagnosis, prevention, and treatment. Today, more than half of all people diagnosed with cancer are cured. However, some forms of the disease remain frustratingly difficult to treat. For those people who cannot be cured, modern treatment can significantly improve quality of life and may extend survival.
You already know that not smoking, maintaining a healthy weight, and drinking alcohol in moderation are keys to avoiding cancer. But what if you want to take cancer prevention one step further? What else can you do? Simple, say the experts — eat right.
Though factors outside our control, such as genetics and environment, do play large roles in the development of cancer, a good diet can tip the scales in your favor.
Research shows that dietary patterns are closely associated with the risk for several types of cancer. The American Cancer Society estimates that as many as 35% of cancer deaths may be related to dietary factors.
“Diets low in fat and high in fiber, fruits, vegetables, and grain products are associated with reduced risks for many cancers,” says Elaine Magee, MPH, RD, author of Tell Me What to Eat to Help Avoid Breast Cancer and Eating Well for a Healthy Menopause, among others. In one recent two-year study, she says, non-melanoma skin cancer patients on a 20%-of-calories-from-fat diet had five times fewer new skin cancers at the end of the study compared with patients in the typical 38%-of-calories-from-fat control group.
In another recent study, says Magee, a lower-fat diet appeared to decrease breast-tissue density in menopausal women, which may decrease breast cancer risk.
Simple Plan
These American Institute for Cancer Research recommendations on diet and lifestyle can provide a starting point for your own cancer-prevention eating plan:
Don’t eat more than 3 ounces of red meat daily — about the size of a deck of cards.
Limit fatty foods.
Avoid salty snacks, and use herbs and spices instead of salt as seasoning.
Men should limit alcoholic drinks to two per day; women, to one per day.
Do not eat charred food.
Avoid being overweight. Limit weight gain during adulthood.
Take an hour’s brisk walk (or get equivalent exercise) daily.
Although Americans are slowly adopting healthier diets, a large gap remains between recommended dietary patterns and what we actually eat. According to the CDC, only about 25% of adults in the U.S. eat the recommended five or more servings of fruits and vegetables each day.
“Eating five to nine servings of fruits and vegetables every day will do a lot to decrease cancer risk,” says Melanie Polk, RD, director of nutrition for the American Institute of Cancer Research, or AICR.
Getting that many servings doesn’t have to be hard, says Polk.
“Make it simple,” she says. “Add a handful of blueberries to your cereal in the morning. If you’re having a sandwich at lunch, throw in lots of tomato slices as well as lettuce. Broccoli can be added to soups or sprinkled over pizza with olives, onions, and mushrooms. Instead of having a packaged snack in the afternoon, have an apple or banana. It all helps.”
Plant foods appear to be most protective against cancer. They are rich in fiber, antioxidants, and helpful phytochemicals.
“Preliminary evidence supports the speculation that substances in flaxseedmay help block substances that promote cancer,” says Magee. “Omega-3 fatty acids, which are found in fish and certain plant foods, including flaxseed, have been shown in animal studies to slow or prevent the growth of certain cancers.”
Diet for High-Risk People
A good diet can even help those with a family history of certain cancers beat the odds.
“A history of cancer in the family doesn’t mean that every person in the family will get it,” says Polk. “For someone at high risk, diet should be included as part of an early-detection screening plan set up by their doctor.”
For the person already diagnosed with cancer, the nutrition picture is a little murkier. No single answer serves everyone.
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