How to Avoid Cancer: Reducing Your Risk for 9 Different Cancers

One in three women. One in two men. That’s how many of us can expect to be diagnosed with cancer in our lifetimes.

Of course, those are averages. A smoker is 25 times more likely to get lung cancer than a nonsmoker. Tobacco alone accounts for about a third of all cancer deaths in the U.S. Back when cigarettes were still deemed healthy, people weren’t worrying about how to avoid cancer nearly as much.

But smoking isn’t the only preventable cause of cancer. Experts estimate that we could dodge up to a third of all cancers by eating healthier, eating less, and moving more. No one can guarantee that you won’t get cancer. But you can lower your cancer risk.

Cancer is the leading cause of death among men and women under age 85. Here’s a snapshot of cancers that are linked to diet, weight, or exercise. For each one, we also list some key risk factors that—except for smoking—you can’t change.

How to Avoid Breast Cancer

One out of every eight women will be diagnosed with breast cancer in her life time. Five-year survival rates are good (85 to 99 percent) unless tumors have metastasized (25 percent). Death rates have dropped since 1989, but nowhere near enough.

You have a higher risk if you:

  • are a woman 65 or older
  • have a relative—especially a mother, sister, or daughter—who had breast cancer
  • have mutations in genes (like BRCA1 and BRCA2) found in families with high rates of breast cancer
  • had menstrual periods that began before age 12 or menopause that began after 55
  • were older than 30 when you had your first child
  • never gave birth
  • took hormones after menopause
  • have dense breast tissue (seen on a mammogram)
  • have abnormal breast cells (atypical hyperplasia or carcinoma in situ)

How to Avoid Breast Cancer with Diet, Weight Loss and Exercise

“What’s changed in the last few years is a greater emphasis on cancer subtypes,” says Regina Ziegler of the Division of Cancer Epidemiology & Genetics at the National Cancer Institute. “Researchers wonder if different subtypes have distinct causes.”

For example, breast tumors that have estrogen receptors (called estrogen-positive) and those that don’t (estrogen-negative) may be fueled by different risk factors.

“Being overweight or obese is a stronger risk factor for estrogen-positive cancer,” notes Ziegler.

Among postmenopausal women who take no hormones, those who are overweight or obese have nearly double the risk of estrogen-positive breast cancer compared to similar women who are lean.Those heavier women have only a 60 percent higher risk of estrogennegative breast cancers.

“Alcohol is also a stronger risk factor for estrogen-positive cancer,” says Ziegler. In one recent study, women who drank one to six servings of alcohol a week had a 29 percent higher risk of estrogen-positive cancer than women who never drank alcohol. Those who drank at least seven servings a week had a 48 percent higher risk. But there was no link with the less common estrogen-negative tumors.

In contrast, “eating more fruits and vegetables, especially vegetables, may be protective for estrogen-negative tumors,” says Ziegler. When researchers pooled data from 20 studies on roughly 993,000 women, women who ate the most vegetables had an 18 percent lower risk of those tumors than women who ate the least.

“The percentage of breast cancer that’s estrogen-negative is higher in younger than in older women,” notes Ziegler. And those tumors are typically harder to treat.

On the other hand, exercise seems to lower the risk of both estrogen-positive and estrogen-negative breast cancer.

“With physical activity, the big question is whether it reduces risk beyond its influence on weight gain,” says Ziegler. “We don’t know.”

It’s also not clear how extra pounds boost the odds of postmenopausal breast cancer. “For a long time, people thought that increased estrogen levels in the breast were the main explanation,” says Ziegler.

After menopause, fat cells, not ovaries, are the chief source of estrogen. “If you have more fat cells, they produce more estrogen, and estrogen stimulates breast cell proliferation,” she explains. “But people now believe that insulin and possibly inflammation also play a role.”

For example, a recent study found that women who had high insulin levels had double the risk of breast cancer, whether or not they were overweight.

Still, adds Ziegler, “you’re more likely to have high insulin levels if you’re heavier and inactive.”

Warning signs: a painless lump in the breast or underarm area. Less common symptoms: thickening, swelling, distortion, tenderness, skin irritation, redness, scaliness, dimpling, puckering, pitting, discharge, or nipple turned inward.

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How to Avoid Colorectal Cancer

It’s the third most common cancer in both men and women, and the second most common in nonsmokers.

Fortunately, the incidence has been steadily dropping since the late 1990s, and death rates have fallen for longer. That’s partly because screening tests (like colonoscopies) enable doctors to remove polyps that may turn into cancer.

You have a higher risk if you:

  • are 50 or older
  • have a parent, brother, sister, or child who had colon cancer or polyps
  • have ever had colon polyps
  • have ulcerative colitis or Crohn’s disease
  • smoke cigarettes

How to Avoid Colorectal Cancer with Diet, Weight Loss and Exercise

If you need another reason to lose—or not gain—extra pounds and to get up off the couch, here it is.

“Compared to people who are normal weight, we see an increased risk in people who are overweight and the highest risk in people who are obese,” says Amanda Cross, a cancer epidemiologist at Imperial College London.

Why? Extra weight boosts levels of insulin and inflammation, which may nudge tumors to keep growing. Being active may cut your risk because it curbs insulin.

“Many studies are now looking not just at walking, running,or other physical activity but at sedentary behavior—how many hours you spend watching TV or sitting at a computer,” notes Cross.

It doesn’t matter whether you walk, run, swim, or dance. “Any exercise is better than no exercise,”she says.

Eating less meat may also protect the lower GI tract. In studies that track people for years,“individuals who consume the most red meat or processed meat have a higher risk of colorectal cancer,” says Cross.

Those types of studies can’t prove that meat causes cancer, she cautions. “But the data is consistent across most large studies conducted around the world.”

So far, researchers have fingered three suspects in meat.“There are the heterocyclic amines and polycyclic aromatic hydrocarbons that are formed when meats are cooked well done by high-temperature cooking methods such as grilling or barbecuing,” says Cross.

The third suspect: the N-nitroso compounds that can form in processed meats like bacon, sausage, and lunch meats. “They’re also formed in the gut when any red meat is consumed,” adds Cross.

“All three are carcinogenic in laboratory animals.”

In contrast, people who consume more milk or calcium have a lower risk of colon cancer. And in one study, people who had precancerous lesions were less likely to get another if they were given a calcium supplement (1,200 mg a day).

“The evidence for meat, obesity, and physical activity is more convincing,” says Cross. “But milk and calcium probably decrease risk.”

Vitamin D may also protect the colon. “That’s the one cancer site where the evidence is starting to look more compelling,” says Christian Abnet of the Division of Cancer Epidemiology & Genetics at the National Cancer Institute.

It would take a trial that gave people either vitamin D or a placebo to nail the answer. “A number of large trials are going on right now,” notes Abnet. “But they may not have enough cases of colorectal cancer to answer the question.”

Warning signs: diarrhea or constipation, feeling that your bowel doesn’t empty completely, blood (bright red or very dark) in your stool, narrow stools, gas pains or cramps, feeling full or bloated, unintended weight loss, fatigue, nausea, vomiting.

How to Avoid Esophageal Cancer

Esophageal cancer is actually two diseases. Squamous cell carcinoma is more common in smokers and heavy drinkers. Adenocar- cinoma is linked to obesity and acid reflux. On average, only 18 percent of patients are alive five years after diagnosis.

You have a higher risk if you:

  • are over 55
  • are male
  • use tobacco
  • have Barrett’s esophagus (for adenocarcinoma risk)

How to Avoid Esophageal Cancer with Diet, Weight Loss and Exercise

“About 80 to 90 percent of the squamous esophageal cancer in the United States can be explained by tobacco and alcohol,” says the National Cancer Institute’s Christian Abnet. “But adenocarcinoma is very different.”

Tobacco is still a factor, but not the major one. Instead,“you see an excess risk in people who are overweight or obese and in people with reflux disease.”

When stomach acid backs up, it can damage the cells that line the esophagus. That can lead to Barrett’s esophagus— when esophageal cells get replaced by gland-like cells that resemble the acidresistant cells that line the stomach.

But there’s no need to panic.

“Reflux disease is very common,” says Abnet. “Something like 20 percent of the U.S.adult population reports weekly reflux. But very,very few of them are going to get esophageal adenocarcinoma. It’s still a rare cancer.”

So people with reflux shouldn’t stay up at night worrying.

“They should focus on preventing the symptoms, not preventing cancer,” says Abnet.

“Upper GI cancers are not so common in the United States, so we emphasize eating a diet that’s optimal for overall health. You have a much higher risk of dying from heart disease than from esophageal cancer.”

Warning signs: painful or difficult swallowing, chest pain, unintended weight loss, heartburn, a hoarse voice or cough that doesn’t go away.

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How to Avoid Liver Cancer

Liver cancer is a killer. Five-year survival rates are 30 percent if the cancer is diagnosed early, but 3 percent if it has metastasized. And the incidence has doubled in both men and women in the last two decades (men have triple the risk of women). Obesity, diabetes, and hepatitis may explain why. The CDC recommends that baby boomers get tested (once) for hepatitis C.

You have a higher risk if you:

  • have chronic hepatitis B or C infection
  • have diabetes
  • have alcoholic liver disease or cirrhosis
  • smoke cigarettes

How to Avoid Liver Cancer with Diet, Weight Loss and Exercise

It’s not clear why liver cancer has spiked in recent years, but the obesity epidemic bears some of the blame.

“In the past, the disease was really driven by hepatitis B and hepatitis C,” says the National Cancer Institute’s Christian Abnet. “And in countries that still have a lot of hepatitis B, that’s still the major risk factor. But obesity is becoming a more important risk factor in the United States.”

Obesity leads to non-alcoholic fatty liver disease. When the body runs out of room to store excess calories, the fat tissue spills over into muscles and the liver, where it doesn’t belong.

“It’s thought that this intra-organ fat can lead to inflammation,” explains Abnet. And inflammation may set the stage for tumors.

Of course, alcoholic fatty liver disease also raises the risk of cancer, which seems to kick in largely among heavy drinkers. “Most of the data suggest that when people get to three drinks a day, that’s when they start to see adverse effects,” says Abnet.

One potential new ally in the fight against liver cancer: coffee. In a recent study, people who drank two or three cups a day had a 40 percent lower risk of liver cancer than those who drank none.

“And in a 2009 study of people who had failed traditional therapy for hepatitis C,” says Abnet, “liver disease was less likely to progress in people who drank at least three cups of coffee a day.” (That’s not much more than one venti at Starbucks.)

How might java protect the liver?

“There’s pretty good evidence that both decaf and caffeinated coffee can lower the risk for type diabetes,” notes Abnet.“Something in coffee may reduce insulin resistance or inflammation.”

Warning signs: abdominal pain or swelling, hard lump below rib cage on right side, yellow skin or whites of eyes, loss of appetite, unintended weight loss, weakness.

How to Avoid Lung Cancer

Death rates have been dropping in men since 1991 and in women since 2003, thanks to less smoking.

Only 15 percent of patients are diagnosed at an early stage, when five-year survival rates are 54 percent. More than half of patients are diagnosed after the cancer has metastasized, when five-year survival plummets to 4 percent.

You have a higher risk if you:

  • smoke or have smoked tobacco
  • have had long-term exposure to radon, asbestos, diesel exhaust, air pollution,or secondhand smoke
  • have a parent or sibling who had lung cancer

How to Avoid Lung Cancer with Diet, Weight Loss and Exercise

It’s clear that taking high doses of vitamin E doesn’t lower your risk of lung cancer, and that if you’re a smoker, taking high doses of beta-carotene (42,000 to 50,000 IU a day) may raise your risk.

Other links are still early leads. For example, a 2010 study of 500,000 healthy Europeans found a 56 percent lower risk of lung cancer in people with higher blood levels of vitamin B-6.

“It’s not clear if vitamin B-6 or other Bvitamins—or some characteristics of people who eat vitamin-B-rich diets— explains the link,” cautions the National Cancer Institute’s Regina Ziegler.

On the downside, men who reported eating more red or very-well-done meat had a higher risk of lung cancer.

The study tried to carefully account for smoking, but “lung cancer is tricky,” notes Imperial College London’s Amanda Cross. “It’s very difficult to tease apart the effects of smoking and meats because smokers tend to eat more red and processed meats.”

How might red or well-done meat increase the risk of not just lung but colorectal, pancreatic, and other cancers?

“If you give animals N-nitroso compounds, heterocyclic amines, or polycyclic aromatic hydrocarbons, tumors will pop up in all sorts of organs, so it’s not surprising that we see an association for multiple cancers,” says Cross.

Warning signs: abdominal pain or swelling, hard lump below rib cage on right side, yellow skin or whites of eyes, loss of appetite, unintended weight loss, weakness.

How to Avoid Ovarian Cancer

Roughly 60 percent of patients are diagnosed after their ovarian cancer has metastasized, when five-year survival rates are only 27 percent. A blood test for CA-125 (a protein produced by many ovarian cancers) is not a good screening tool. In a trial on 78,000 women, those who were randomly assigned to have annual screening with a CA-125 test and a transvaginal ultrasound had no lower death rates from ovarian cancer than those who had “usual care.”

You have a higher risk if you:

  • have had breast cancer
  • have a mother or sister who had cancer of the ovary or breast
  • have mutations in genes (like BRCA1 and BRCA2) that are found in families with high rates of ovarian cancer
  • never gave birth
  • take or took estrogen (without progestin) within the last three year

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How to Avoid Ovarian Cancer with Diet, Weight Loss and Exercise

“Consuming dairy products…has been shown to increase one’s risk of ovarian cancer,” says “The Dr. Oz Show” website.

“Studies have found that people who ate 30 grams of lactose a day increased their ovarian cancer risk by 20 percent. That’s one glass of milk or one cup of ice cream!”

Relax. Dr. Oz hasn’t done his homework. For starters, one glass of milk has 12 grams of lactose and a cup office cream has about 10 grams. What’s more, it’s not even clear that dairy or lactose matters.

When it comes to ovarian cancer, “dairy has been studied more than any other food,”says Melissa Merritt, a research fellow in cancer epidemiology at Imperial College London. “But there’s no consistent evidence linking dairy to ovarian cancer.”

For example, when researchers pooled data on roughly 550,000 women in 12 studies, they found a “weak, marginally significant” link between lactose and ovarian cancer—and that was only if women got the lactose you’d get in at least three cups of milk per day. They found no link with cheese, yogurt, or calcium.

But “when we looked at the Nurses’ Health Study, we didn’t see an association between lactose intake and ovarian cancer risk,” adds Merritt. “That was reassuring.” Her bottom line: “I wouldn’t advise women to change their dairy intake to avoid ovarian cancer.”

Extra weight may also raise the risk, but only in women who have never taken hormones after menopause.

Your best bet, says Merritt, is to “follow advice for preventing other cancers.”

Warning signs: swollen or bloated abdomen, gas, constipation, pressure or pain in the abdomen or pelvis, the need to urinate often, heavy vaginal bleeding, bleeding after menopause, lump in pelvic area, feeling full quickly.

How to Avoid Panceatic Cancer

It’s the fourth-leading cancer killer, in part because there are no good screening tests and no good treatments. More than half of patients are diagnosed after the cancer has metastasized,when five-year survival rates average just 2 percent.Even if the cancer hasn’t spread at all, only 26 percent of patients survive for five years.

You have a higher risk if you:

  • have a parent or sibling who had pancreatic cancer
  • have type 2 diabetes
  • smoke cigarettes
  • have chronic pancreatitis

How to Avoid Pancreatic Cancer with Diet, Weight Loss and Exercise

“The connection between pancreatic cancer and overweight or obesity is quite consistent,”says the National Cancer Institute’s Christian Abnet.

After pooling data on nearly 850,000 people in 14 studies, researchers estimated that overweight people had an 18 percent higher risk and that obese people had a 47 percent higher risk. Why?

“Excess weight could raise the risk by inducing type 2 diabetes,”notes Abnet. People with diabetes have a 37 percent higher risk.

But it’s not clear whether diabetes causes pancreatic cancer or vice versa. “Diabetes could be induced by an undiagnosed tumor in the pancreas,” says Abnet. “You could develop diabetes because your pancreas is no longer functioning normally.”

Red meat is also a suspect. In a NIHAARP study of roughly 530,000 people, the risk of pancreatic cancer was higher in men who ate the most red meat—or the most meat cooked at high temperatures— than in those who ate the least.

“We may not have seen an elevated risk in women because they ate less meat than men,” says Imperial College London’s Amanda Cross.

Warning signs: pain in the upper or middle abdomen or back, dark urine, pale stools, yellow skin and eyes, nausea, vomiting, feeling very tired, loss of appetite, unintended weight loss.

How to Avoid Prostate Cancer

The incidence of prostate cancer spiked in the early 1990s,s oon after men started getting PSA tests. But most prostate cancers are not life threatening.

“The strongest predictor of prostate cancer is getting a PSA test,” says Lorelei Mucci,associate professor of epidemiology at the Harvard T.H. Chan School of Public Health.

That doesn’t mean that men shouldn’t get their PSA tested, she adds. The trick is to distinguish the harmless from the dangerous cancers. That’s why many newer studies look only for clues to the risk of aggressive or lethal cancers, rather than all prostate cancers.

You have a higher risk if you:

  • are over 50
  • have a father, brother, or son who had prostate cancer
  • have had a biopsy that found highgrade prostatic intraepithelial neoplasia
  • are of African ancestry

How to Avoid Prostate Cancer with Diet, Weight Loss and Exercise

Does calcium raise the risk of prostate cancer? “It’s associated with advanced or fatal prostate cancer only at very high intakes,” says Mucci.

In a study that followed more than 47,000 health professionals for 24 years, a higher risk of advanced or fatal prostate cancer showed up only in men who got at least 2,000 milligrams of calcium a day.

You’re not likely to reach 2,000 mg without a calcium supplement, notes Mucci. (Expect 300 mg in a cup of milk, about 200 mg in a typical slice of cheese or container of yogurt, roughly 300 mg in the rest of a typical diet, and about 200mg in most multivitamins for men.)

But it wasn’t clear that it was calcium— and not phosphorus—that explained the increased risk of prostate cancer. (Phosphorus is found not just in dairy foods and meat but in phosphate additives in processed and restaurant foods.)

Extra pounds also matter. “Being overweight or obese is associated with an increased risk for more advanced prostate cancer,” says Mucci.

On the bright side, research suggests that the lycopene (or something else) in cooked tomatoes, tomato sauce, etc., may protect the prostate.

“Men who consume two to three tomato-based foods per week have a lower risk of developing a more advanced prostate cancer,” says Mucci.

And, she adds, in a recent study on men with prostate cancer, “fewer new blood vessels were being formed by the tumors of men who had consumed high levels of lycopene compared to men who had not.” Tumors need to grow blood vessels to spread.

Researchers are also studying men who have been diagnosed with prostate cancer to see what might lead to a recurrence.

Among the findings: “Men who did brisk walking had a lower risk of recurrence and a lower risk of mortality after diagnosis,” notes Mucci.

However, “recurrence is not a very strong predictor of prostate cancer mortality,” she cautions.

“Less than 20 to 25 percent of men who have a recurrence go on to develop metastatic disease. The big, unanswered question is whether a change in lifestyle or diet can improve survival, especially for men with advanced disease.”

Warning signs: weak or interrupted urine flow, difficulty starting or stopping urine flow, the need to urinate often especially at night, sudden urge to urinate, blood in the urine or semen, pain or burning with urination, pain in the back, hips, or pelvis that doesn’t go away.

How to Avoid Uterine Cancer

Cancers of the endometrium (the lining of the uterus) have inched up in recent years. The obesity epidemic may explain why. Five-year survival rates are 82 percent, in part because most cancers are caught early.

You have a higher risk if you:

  • never gave birth
  • started menopause after age 55
  • have taken estrogen without progestin
  • have diabetes
  • have high blood pressure

How to Avoid Uterine Cancer with Diet, Weight Loss and Exercise

“If you are overweight or obese, you have a higher risk of endometrial cancer,” says Melissa Merritt of Imperial College London. “The evidence is convincing.”

British researchers recently estimated that 40 percent of cancers of the uterus are due to extra pounds. Excess weight may promote tumors by boosting both estrogen and insulin levels.

The evidence isn’t quite “convincing” for exercise, but studies suggest that it does lower your risk.

For example, in one large study, the risk of endometrial cancer was higher among women who sat at least five hours a day. But exercise was linked to a lower risk only among overweight or obese women who did vigorous activity.

And there are hints that coffee may give you an edge.

“Two large studies found that a high intake of coffee was associated with a lower risk of endometrial cancer,” says Merritt. “But a third did not.”

Her view: “It’s worth looking further.”

Warning signs: abnormal vaginal bleeding or spotting, discharge, pain during sex, pain in the pelvic area, pain or difficulty emptying the bladder.

The Bottom Line

To reduce your risk of cancer:

  1. Don’t use tobacco
  2. Lose (or don’t gain) excess weight
  3. Limit red and processed meat
  4. Limit alcohol to 2 servings a day (men) or as little as possible (women)
  5. Get at least 30 minutes of exercise a day

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