Plan to Prevent or Reduce Cancer

A P R I L 2 0 1 9 | N U T R I T I O N A C T I O N H E A LT H L E T T E R 3

BREAST

One in eight women will be diagnosed with breast cancer in her lifetime. The � ve-year survival rate averages 90 per- cent. That’s because most tumors are detected early.1

You have a higher risk if you: ● are an older woman ● have excess weight (and you’re post-

menopausal) ● are sedentary ● consume alcohol often ● have a relative—especially a mother,

sister, or daughter—who was diag- nosed with 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 age 55

● were older than 30 when you had your � rst child

● took estrogen and progestin after menopause

● have dense breast tissue (seen on a mammogram)

● have abnormal breast cells (atypical hyperplasia or carcinoma in situ)

DIET, EXERCISE, ETC.

Gaining weight—even as little as an extra 10 to 20 pounds—is linked to an increased risk of breast cancer after menopause.2 Why?

“We have compelling evidence that higher blood levels of estrogen are associated with an increased risk of postmenopausal breast cancer,” says Regina Ziegler, a former researcher at

the National Cancer Institute’s Division of Cancer Epidemiology & Genetics.

“In postmenopausal women, the ovaries no longer produce estrogen,” ex- plains Ziegler, “so the dominant source is estrogens that are made in fat tissue in the breast and elsewhere.” (Dominant, that is, unless women take replacement hormones, which also raise risk.)

Excess insulin and in� ammation may also spur tumors to grow.

Among postmenopausal women not taking hormones, those with the highest insulin levels had twice the risk of breast cancer—and those with the highest levels of c-reactive protein (a marker of in� ammation) had a 67 percent higher risk—than those with lower levels.3,4

Also, women who have even a few servings of alcohol a week have a 10 per- cent higher risk of breast cancer than those who don’t drink. One to two daily drinks were linked to a 19 percent higher risk.5

In contrast, “physical activity is protective,” notes Ziegler, “though it’s not clear whether it works by itself or by preventing weight gain.”

Other possible protectors: “The evidence has strengthened that vegeta- bles and fruits may be associated with a reduced risk of breast cancers, especially estrogen-negative and other aggressive tumors,” says Ziegler.6 (Estrogen-nega- tive cancers are less common, but more dif� cult to treat.)

“Though we can’t say de� nitively that fruits and vegetables can help prevent breast cancer, they’re worth eating to lower the risk of strokes, heart attacks, type 2 diabetes, and obesity.”

Warning signs: a painless lump in the breast or underarm area. Less-common symptoms: breast pain or heaviness, thickening, swelling, redness, discharge, nipple turned inward.

COLON & RECTUM

It’s a success story. The death rate from colorectal cancer in 2016 was less than half of what it was in 1970.1 One trou- bling sign: while colorectal cancer is dropping in older adults, it’s inching up in adults younger than 55.

You have a higher risk if you: ● are 50 or older ● have excess weight ● are sedentary ● eat processed or red meats often ● have a parent, brother, sister, or child

who was diagnosed with colon cancer ● have ever had colon polyps ● have ulcerative colitis or Crohn’s

disease ● have type 2 diabetes ● smoke tobacco

DIET, EXERCISE, ETC.

“It’s so frustrating that colorectal cancer is still such a massive killer around the world, because there is so much we can do to reduce the incidence,” says Amanda Cross, a cancer epidemiologist at Imperial College London.

Your � rst step: get a colonoscopy or another screening test.

“Screening has had a dramatic effect on the incidence of colorectal cancer in those over age 50,” says Cross. “Before screening, the incidence was increasing. Now it’s coming down.”

And stay in shape. “If you’re active and not overweight, your risk is lower,” says Cross.7 Healthy insulin levels may help explain why.

“Physical activity increases insulin sensitivity, which can curb high insulin levels,” she explains.

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Cancer is the #1 killer of Americans aged 45 to 84. Smoking accounts for

about 30 percent of those deaths. Lifestyle—excess weight, inactivity, poor

diet, and alcohol—accounts for another 16 percent. Here’s what may help.

B Y B O N N I E L I E B M A N

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4 N U T R I T I O N A C T I O N H E A LT H L E T T E R | A P R I L 2 0 1 9

Excess weight often leads to excess insulin, but people with higher insulin levels have a higher risk even if they’re lean.8

More than two servings of alcohol a day for men—or one for women—is also a risk factor.7 The acetaldehyde that’s made when the body metabolizes alco- hol may be carcinogenic to cells lining the colon.

In 2015, the International Agency for Research on Cancer concluded that each daily (3½ oz.) serving of red meat or (2 oz.) serving of processed meat like bacon, ham, sausage, or hot dogs is linked to roughly an 18 percent higher risk of colorectal cancer. The evidence was stronger for processed meat.9

Carcinogenic N-nitroso compounds may be partly to blame.

“Companies now add less nitrite and add ascorbic acid to processed meats to inhibit the formation of N-nitroso compounds, but they can still form in the body,” says Cross.

Meat may harbor other carcinogens. “There is evidence from animals that

two other groups of compounds—het- erocyclic amines and polycyclic aromat- ic hydrocarbons—are carcinogenic,” says Cross. “And both are found in processed and unprocessed red meats cooked at high temperatures.”

Warning signs: diarrhea or constipa- tion, feeling that your bowel doesn’t empty completely, blood (bright red or

very dark) in your stool, rectal bleeding, narrow stools, gas pain, cramps, feeling full or bloated, unintended weight loss, fatigue, decreased appetite.

ESOPHAGUS

“Esophageal cancer is very rare in the United States,” says Christian Abnet, chief of the metabolic epidemiology branch at the National Cancer Institute. That’s good, because the � ve-year survival rate is 19 percent.

You have a higher risk if you: ● are over 55 ● have excess weight ● are male ● smoke or chew tobacco ● have acid re� ux or Barrett’s esophagus

DIET, EXERCISE, ETC.

Esophageal cancer is really two diseases. Smoking and heavy drinking are

major risk factors for esophageal squa- mous cell carcinoma. But it’s esophageal adenocarcinoma that’s on the rise, and the obesity epidemic may explain why.1

“Obesity causes in� ammation and seems to induce re� ux disease by put- ting pressure on your lower esophageal sphincter,” explains Abnet, referring to

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Lung cancer death rates in both men and women are dropping, but the disease still accounts for about a quarter of all cancer deaths. Uterine and cervical cancers are combined because they were not reported separately until 1973.

Source: Cancer Facts & Figures 2019, American Cancer Society.

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Liver

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Pancreas

Leukemia

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the doorway between your esophagus and stomach.

“That pressure makes the sphincter more likely to be open,” he adds. “And then you’re more likely to have acid re� ux, which seems to be part of the carcinogenic process.”

But people with re� ux needn’t panic. “Re� ux is very common,” says Abnet.

“About 20 percent of U.S. adults have it. But the vast majority don’t get esopha- geal cancer.”

Re� ux can cause Barrett’s esophagus, which means that the cells lining your lower esophagus have morphed into cells like those that line your stomach or small intestine.

People with Barrett’s are 24 times more likely to get esophageal cancer than others. But only an extra 24 out of every 10,000 of them develop the cancer each year compared to people without Barrett’s.10

“Some doctors recommend an upper endoscopy to assess whether you have Barrett’s if you’re over 50, had long- standing re� ux disease, and are male,” says Abnet. (The risk in women is low.)

“Twenty years ago, people with Bar- rett’s were told to have an endoscopy every year. There was no evidence for that, but it was done in an abundance of caution because early esophageal cancer can be successfully treated, while late esophageal cancer is rarely successfully treated.”

But now most doctors recommend

U.S. Death Rates from Most Major Cancers

A P R I L 2 0 1 9 | N U T R I T I O N A C T I O N H E A LT H L E T T E R 5

repeated endoscopies only if a biopsy � nds precancerous changes.

“If a thorough endoscopy � nds Bar- rett’s but no precancerous cells, patients may be told to just go about their busi- ness, but to check with their doctor in � ve years to discuss further follow-up,” says Abnet.

Warning signs: painful or dif� cult swallowing, chest pain, unintended weight loss, hoarseness, cough, hiccups, vomiting, bone pain, black stools.

LIVER

Liver cancer rates are rising more rapid- ly than those of any other cancer. Since 1980, the incidence has tripled and the death rate has doubled. The � ve-year survival rate is only 18 percent.1

You have a higher risk if you: ● have chronic hepatitis B or C infection ● have excess weight ● have type 2 diabetes ● are a heavy drinker ● smoke tobacco

DIET, EXERCISE, ETC.

“Excess weight, nonalcoholic fatty liver disease, and diabetes are greatly con- tributing to higher rates of liver cancer in the U.S.,” says Katherine McGlynn, senior investigator in the metabolic epidemiology branch at the National Cancer Institute.11

It’s not clear how they might increase risk, but it is clear that they are all linked.

“Excess weight increases fat storage

in the liver and the risk of insulin resistance and type 2 diabetes,” says McGlynn.

And those changes are linked to in- � ammation, which can cause scarring.

“There’s a whole cascade of patholo- gy,” explains McGlynn. “In� ammation can lead to liver disease, starting with scarring and progressing all the way to cirrhosis.”

Heavy drinking and smoking are also risk factors. On the plus side, coffee may protect your liver.12

“Coffee has been associated with a decreased risk in study after study,” says McGlynn. “The decrease is seen with both caffeinated and decaffeinated, suggesting that an ingredient other than caffeine is providing the protection.”

What may come as a surprise: since 2012, the Centers for Disease Control and Prevention (CDC) has advised all baby boomers—anyone born between 1945 and 1965—to get a hepatitis C test.13

“The virus circulated in the blood supply until 1992,” says McGlynn.

“Before then, anyone who had a blood transfusion or other medical encoun- ter in which they came in contact with blood could have become infected with the virus. And many infections have no symptoms, so people might never know they were infected.”

If you do have hepatitis C (an in� am- mation of the liver), it can be cured.

“The drugs are expensive,” says McGlynn, “but more insurance compa- nies are covering them because the high price is still cheaper than paying for the long-term consequences.”

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

LUNG

Since 1990, death rates for lung cancer have dropped roughly in half in men, and they’ve dropped by about a quarter in women since 2002, thanks to declines in smoking. But lung cancer is still the No. 1 cancer killer...by far.1

You have a higher risk if you: ● smoke or have smoked tobacco ● have had long-term exposure to radon,

asbestos, diesel exhaust, air pollution, radiation, or secondhand smoke

DIET, EXERCISE, ETC.

Roughly 80 percent of lung cancer deaths are caused by smoking.1 Smokers are 25 times more likely to be diagnosed with the disease than nonsmokers.

“The impact of smoking dwarfs all other risk factors,” says Meir Stampfer, professor of epidemiology and nutri- tion at the Harvard T.H. Chan School of Public Health.

Less smoking, not better treatment, largely accounts for falling death rates. Five-year survival rates are still only around 20 percent.

Links with diet and weight are uncer- tain. In a recent study of roughly 1.4 mil- lion people, smokers who reported eating more saturated fat had a higher risk, while those who ate more polyun- saturated fat had a lower risk.14

And in an analysis of 1.6 million people, those with larger waists had a higher risk, regardless of their weight.15

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Estimated number of U.S. cancer deaths for 2019.

Lung 66,020 Breast 41,760 Colon & Rectum 23,380

Pancreas 21,950 Ovary 13,980 Uterus 12,160

Non-Hodgkin Lymphoma 8,460 Brain 7,850

Leukemia 9,690 Liver 10,180

76,650 Lung 31,620 Prostate

27,640 Colon & Rectum 23,800 Pancreas

21,600 Liver 13,150 Leukemia 13,020 Esophagus 12,870 Bladder

11,510 Non-Hodgkin Lymphoma 9,910 Brain

Leading Cancer Killers

6 N U T R I T I O N A C T I O N H E A LT H L E T T E R | A P R I L 2 0 1 9

of cancer in the pancreas cause diabetes? We don’t know.”

And so far, researchers haven’t found a way to do early screening. “You can’t do regular pancreatic biopsies,” says Abnet.

Warning signs: abdominal pain that may radiate to the back, yellow skin and eyes, unintended weight loss, nausea, vomiting.

PROSTATE

One in nine men will be diagnosed with prostate cancer in his lifetime.1 But the � ve-year survival rate is 98 percent. In fact, many of those men need no treat- ment at all (see April 2018, p. 3).

You have a higher risk if you: ● are over 50 ● have a father, brother, or son who was

diagnosed with prostate cancer ● are of African ancestry

DIET, EXERCISE, ETC.

“The evidence has gotten a bit stronger that overweight men are not more likely to be diagnosed with prostate cancer, but they are more likely to die of it,” says Harvard’s Meir Stampfer.19

“That’s also true for physical inac- tivity.20 Reducing your risk of dying of prostate cancer is an added bonus to the myriad of good reasons to maintain a healthy weight and not be inactive.”

Stampfer cautions against taking selenium supplements.

“We have good evidence that they raise the risk of dying of prostate cancer, so men should de� nitely avoid them. 21,22

“And I would avoid separate calcium supplements and juices or milk with added calcium.” Some studies � nd a higher risk of prostate cancer in men who get more than 2,000 milligrams of calcium a day.23

Should men get a PSA (prostate-spe- ci� c antigen) test to screen for prostate cancer? The U.S. Preventive Services Task Force advises men aged 55 to 69

“It’s too early to know if a large waist or saturated fat promotes lung cancer or if unsaturated fats curb the risk,” says Stampfer.

“But we have plenty of evidence that avoiding abdominal obesity and replac- ing saturated fats with unsaturated fats can lower the risk of heart disease and type 2 diabetes.”

Warning signs: persistent cough, short- ness of breath, chest pain, coughing up bloody mucus, voice change, frequent lung infections like pneumonia.

OVARY

The � ve-year survival rate is only 47 per- cent, in part because most patients are diagnosed after the cancer has spread.

You have a higher risk if you: ● have a mother or sister who was diag-

nosed with ovarian or breast cancer ● have been diagnosed with breast cancer ● have mutations in genes (like BRCA1

and BRCA2) that are found in families with high rates of ovarian cancer

● took estrogen alone or with progestin after menopause

● have excess weight

DIET, EXERCISE, ETC.

Excess weight is linked to a higher risk of ovarian cancer.16 “But it’s not a strong risk factor,” says Shelley Tworoger, associate center director of population science at the Mof� tt Cancer Center in Tampa.

Beyond weight, no clear links with diet have emerged.

“Taking oral contraceptives is associ- ated with a lower risk,” says Tworoger.17

“And women with a family history of cancer, particularly breast or ovarian, should speak to a doctor about genetic testing.” Genetics aside, there are no good screening tests.

“Several large trials have shown no survival bene� t for transvaginal ultra- sound and CA 125 as a potential marker for ovarian cancer,” says Tworoger.

What might matter: knowing the symptoms, says the CDC’s “Inside Knowledge about Gynecologic Cancer” campaign.

“A large majority of ovarian cancer patients have symptoms like bloating, feeling full quickly, or abdominal pain for a substantial period of time before they’re diagnosed,” says Tworoger. “If those symptoms persist for no identi� - able reason, it’s worth getting tested.”

Warning signs: abdominal swelling, persistent bloating, pain in the abdo- men, back, or pelvis, the need to urinate often or urgently, feeling full quickly.

PANCREAS

Pancreatic cancer accounts for just 3 per- cent of cancer diagnoses, but the third highest number of cancer deaths. “It’s got the worst � ve-year survival except for some rare cancers,” says the Nation- al Cancer Institute’s Christian Abnet.

You have a higher risk if you: ● have a parent or sibling diagnosed

with pancreatic cancer ● have excess weight ● have type 2 diabetes ● smoke or chew tobacco ● have chronic pancreatitis

DIET, EXERCISE, ETC.

“Avoiding excess weight is important for pancreatic cancer,” says Abnet. “That also helps prevent type 2 diabetes, which is linked to pancreatic cancer.”

Why might extra pounds matter? “Obesity induces in� ammation, a hallmark of cancer,” notes Abnet. People with a large waist also have a higher risk, regardless of their weight.18

“In people with abdominal obesity, you’re getting more in� ammation and more fatty tissue in� ltrating organs,” Abnet explains.

The link with type 2 diabetes is un- clear, he adds.

“Does diabetes increase the risk of pancreatic cancer or does the beginning P

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A P R I L 2 0 1 9 | N U T R I T I O N A C T I O N H E A LT H L E T T E R 7

to discuss the pros and cons with their doctor, given the risk of overdiagnosis and overtreatment.

“I recommend a PSA test every few years for men who expect to live at least 12 to 15 more years,” says Stampfer. “If your PSA is below 1.0 at age 60, the risk is so low that you can stop testing.”

His worry: “The incidence of ad- vanced disease at diagnosis seems to be going back up. Some potentially preventable prostate cancer deaths are being missed. Some guys who didn’t get a PSA test may have missed their chance to be diagnosed and treated earlier.”

But if you have a high PSA—or a biopsy showing cancer—don’t panic.

“The decision to do a biopsy shouldn’t be automatic,” says Stamp- fer. “And if a biopsy fi nds cancer, you should have more tests and consider active surveillance rather than rushing into surgery.”

Warning signs: weak or interrupted urine fl ow, diffi culty starting or stop- ping urine fl ow, need to urinate often es- pecially at night, sudden urge to urinate, blood in the urine, pain or burning with urination, pain in the back, hips, or ribs that doesn’t go away.

UTERUS

Diagnoses and death rates are climbing.1

Black women have double the death rate of white women, possibly because

they are more likely to have an aggressive type of tumor and are often diagnosed later.

You have a higher risk if you:

have excess weight are sedentary started menopause

after age 55 took estrogen with-

out progestin after menopause have type 2 diabetes

DIET, EXERCISE, ETC.

“Obesity is the single most important risk factor for endometrial cancer,” says Immaculata De Vivo, professor of epidemiology at the Harvard T.H. Chan School of Public Health.24 (The endome- trium is the lining of the uterus.)

“It’s one of the cancers that are on the rise because obesity is the main driver,” says De Vivo. “It’s astonishing to me that it accounts for so much of the risk.”

Exercise may help curb risk, in part by preventing weight gain.

“We’ve also seen a protective effect of coffee,” says De Vivo. For example, in the Nurses’ Health Study, women who drank four or more daily cups of coffee— the amount in two Starbucks grandes—had a 25 percent lower risk than those who drank less than one cup a day.25

To help catch endometrial cancer early, see your doctor if you have vaginal bleeding after menopause. “Postmenopausal bleeding is not normal,” notes De Vivo.

But don’t panic. In one recent meta-analysis, postmenopausal bleeding occurred in about 90 per- cent of women with endometrial cancer, but only 9 percent of wom- en with bleeding were diagnosed with the cancer.26

Warning signs: abnormal vaginal bleeding or spotting, discharge, pain during sex, while urinating, or in the pelvic area.

1 cancer.org/research/cancer-facts-statistics/all-cancer- facts-fi gures/cancer-facts-fi gures-2019.html.

2 JAMA 296: 193, 2006. 3 Cancer Res. 75: 270, 2015. 4 J. Natl. Cancer Inst. 107: djv169, 2015. 5 Int. J. Epidemiol. 45: 916, 2016. 6 Int. J. Cancer 144: 1496, 2019. 7 BMC Medicine 12: 168, 2014. 8 PLoS Med. 2016. doi:10.1371/journal.

pmed.1001988. 9 monographs.iarc.fr/wp-content/uploads/2018/06/

mono114.pdf. 10 Gut 67: 418, 2018. 11 Cancer 122: 1757, 2016. 12 Cancer Epidemiol. Biomarkers Prev. 24: 1398, 2015. 13 cdc.gov/hepatitis/populations/1945-1965.htm. 14 J. Clin. Oncol. 35: 3055, 2017. 15 J. Natl. Cancer Inst. 110: djx286, 2018. 16 PLoS Med. 2012. doi:10.1371/journal.

pmed.1001200. 17 Cancer Epidemiol. Biomarkers Prev. 25: 1059, 2016. 18 Ann. Oncol. 26: 2257, 2015. 19 J. Natl. Cancer Inst. 109: djw225, 2017. 20 J. Clin. Oncol. 29: 726, 2011. 21 J. Natl. Cancer Inst. 106: djt456, 2014. 22 J. Natl. Cancer Inst. 107: dju360, 2014. 23 Am. J. Clin. Nutr. 101: 173, 2015. 24 Int. J. Cancer 137: 625, 2015. 25 Cancer Epidemiol. Biomarkers Prev. 20: 2487, 2011. 26 JAMA Intern. Med. 178: 1210, 2018.

To reduce your risk of cancer:

1. Stay away from tobacco.

2. Lose (or don’t gain) excess weight.

3. Limit alcohol to two serv- ings a day for men or one for women.

4. Limit red and processed meats.

5. Fill half your plate with veggies or fruit.

6. Shoot for 20 to 40 minutes a day of any exercise that gets your heart beating faster.

7. When you’re out in the sun, apply a shot glass of “broad spectrum” sunscreen (SPF 30+) every two hours.

8. Avoid tanning beds.

9. Make sure children get vaccines to prevent HPV (human papillomavirus) and HBV (hepatitis B).

10. Go to cancer.org to see the American Cancer Society’s guidelines for when to get a colonoscopy, mammogram, or other screening tests.

11. Go to cancer.gov (the National Cancer Institute) or AICR.org (the American Institute for Cancer Research) to learn more.

The Bottom Line

Thyroid

Breast

Liver

Gallbladder

Upper stomach

Pancreas

Colon and rectum

Adenocarcinoma of the esophagus

Multiple myeloma

Kidneys

Uterus

Ovaries

13 cancers are linked to overweight & obesity

(postmenopausal women)

(cancer of the blood cells)

(cancer in the tissue covering the brain

and spinal cord)

Adapted from: cdc.gov/vitalsigns/obesity-cancer.

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Meningioma

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