Health

Here are some ways you can lower your chances of getting cancer.

Michael Hunter MD

Aug 29, 2020·8 min read

First, the startling headline: Most Americans lack knowledge about the best cancer risk reduction practices, the dangers of e-cigarettes, and available end-of-life care despite an abundance of published data. These are the conclusions of the American Society of Clinical Oncology’s third annual Cancer Opinions Survey results.

Alas, fewer than one-quarter of survey respondents indicated they incorporate cancer prevention practices into their daily lives. Today, I want to talk about the survey before turning to ways that you can decrease your own risk of ever getting cancer.

Here is the scope of the cancer problem: Worldwide, there are over fourteen million individuals with cancer, and approximately eight million deaths from the disease annually. While survival rates are improving, over a half million Americans will die from the disease this year alone.

The survey — conducted online between July 9 and Aug. 10 — included four thousand and one adults (fifty-three percent women, and sixty-three percent white) plus an oversample of eight hundred and fourteen adults with cancer.

Concerned, but not acting

More than half (specifically, fifty-seven percent) of those surveyed had a concern about developing cancer in their lifetime. However, only approximately a quarter indicated they care profoundly and incorporate cancer prevention practices into their daily lives.

This lack of action does not appear to be because of a lack of available information. Indeed, eighty-one percent of the study participants agreed that a wealth of information is available regarding cancer causes. Still, sixty-six percent did not know which sources to trust when looking for this information. Another sixty-four percent agreed that it is hard to know the most important things to prevent cancer.

I was surprised to learn that only twenty-two percent of adults had talked with a doctor about their own cancer risk, with only eighteen percent reviewing options to reduce risk, and twenty-four percent turning to online sources. Only about a third made an obesity-cancer connection, and only about one in three recognized that alcohol increases cancer risk.

Many had wrong impressions. For example, over a quarter thought artificial sweeteners cause cancer, sixteen percent felt cell phone use could result in cancer, and just under ten percent thought there was caffeine could cause cancer.

Let’s turn to some known risk factors associated with cancer. The first, and perhaps most apparent is tobacco use. This is indeed the leading preventable cause of cancer and accounts for over one in five deaths due to cancer worldwide. About half of cigarette users will die of a tobacco-related disease, with an estimated average of thirteen years of life due to its use.

Tobacco increases the risk of lung cancer by up to ten- to twenty-fold. But while we tend to think of the smoking-lung cancer connection, we may not be as aware of the association of tobacco and other cancers. These include malignancies of the nasal cavity, sinuses near the nose, nasopharynx, voice box, esophagus, stomach, pancreas, kidneys, large intestine (colon), bladder, cervix, and (perhaps) prostate cancer.

There’s more: Tobacco in pipes, cigars, smokeless tobacco, and secondhand smoke can increase the risk of cancer. But there is good news, as the health benefits of quitting begin immediately after cessation of the habit.

Next up are environmental exposures. There are over one million skin cancer cases annually, including nearly seventy-thousand cases of the dangerous cancer melanoma in the United States alone, including almost nine thousand deaths secondary to melanoma. Solar radiation is the primary cause of skin cancer, including both melanoma and non-melanoma types.

So what should we do? Limit the time you spend in the sun. I am especially careful between the hours of 10 am and 4 pm. You know the drill: Hats, sunglasses, and covering up. Use a sunscreen, too. And I probably don’t need to tell you to avoid sun tanning beds.

Alas, lung cancer has been associated not only with tobacco exposure but as well with air pollution and indoor radon (a radioactive gas). Arsenic in our water supply (and in rice from specific locations) can result in bladder cancer; the more exposure, the higher the risk of cancer. Typically, municipal water sources are tested, with private drinking wells more likely to have the toxin.

I often talk about physical activity as a means of decreasing cancer risk by a significant amount. Some studies, including those published from Harvard in 1996, point to a sedentary lifestyle linked with five percent of deaths due to cancer. In fact, for non-users of cigarettes, physical activity is perhaps the most important modifiable risk factor for many forms of cancer.

Exercise may reduce your risk of colon, pancreas, liver, stomach, breast, uterus, and other cancers. For example, an analysis of a collection of studies (a meta-analysis) from the Nurses’ Health Study Research Group showed that the risk of colon and rectal cancer was dropped by more than a quarter when comparing the least and most physically active individuals.

Obesity is related to about one-fifth of all cancers. By having a healthy weight, you may lower the risk of a myriad of cancers, including cancers of the esophagus, stomach, colon and rectum, liver, uterus, ovaries, gallbladder, pancreas, kidneys, thyroid, multiple myeloma, meningioma, and breast cancer that occurs after menopause. That is the conclusion of the IARC Working Group, publishing in the New England Journal of Medicine in 2016.

Can you reduce your risk by optimizing your diet? Historical studies have been inconsistent. Research examining the connection between nutrition and cancer risk are incredibly challenging to complete. There can be poor adherence to a prescribed diet, too short follow-up, and other variables that influence cancer risk. Still, we think that dietary fat may be associated with prostate cancer. And, high dietary fat appears to be associated with a higher risk of getting breast cancer.

Intake of high levels of red meat may increase your risk of colon cancer. A meta-analysis discovered a dose-response relationship between red meat consumption and cancer risk: For every hundred grams per day of red meat consumed, there is a relative increase of seventeen percent, or just under a fifth.

It appears that processed meat increases risk, too: The meta-analysis found a relative increase of cancer of eighteen percent (risk increased by about a fifth, or a percent or so) for every hundred grams of red meat eaten daily. I think there is no high-level evidence that meat must be avoided.

Most recommendations are based on observational or lower-level studies.We don’t fully understand why red and processed meat consumption is associated with increased cancer risk. Still, it may be the meat’s heme content, cancer-causing substances created when meat is cooked at high temperatures or animal fat, whether different strategies of animal raising matter remains unknown. I would add that we don’t know whether dairy consumption increases risk.

You may already know that your diet’s higher fiber intake may lower your heart disease and diabetes risk. The relationship between cancer incidence is less clear. What is more apparent is that dietary patterns are associated with cancer incidence and the risk of dying of the disease. Evidence includes the results of a large study looking at a Mediterranean diet (think high intake of fruits and vegetables, nuts, legumes, whole wheat bread, fish, and olive oil) can drop the risk of cancer by up to twelve percent.

Watch the ultra-processed foods, too: One study linked diets high in ultra-processed foods to a more than ten percent increase in cancer overall and breast cancer specifically. You know what you need to do: Watch out for packaged bread and snacks, instant soups, frozen meats, packaged snacks, sodas, etc.

Photo by Roberto Carlos Roman on Unsplash

Excessive consumption of alcohol increases cancer risk. Indeed, the European Prospective Investigation into Cancer and Nutrition study led to the following conclusion:

Alcohol may account for ten percent of cancer risk among men, and three percent among women. This risk appears to be greater for cancer of the upper gastrointestinal tract and the liver.

The Women’s Health Study and the Nurse’s Health Study showed an increased risk of breast cancer with low-to-moderate alcohol consumption. Even as few as three to six standard drinks per week can lead to a small increase in breast cancer risk, and may also raise your chances of getting cancers of the esophagus and oropharynx (including the base of the tongue and the tonsils).

We did not look at ways you can use screening tools such as colonoscopy, mammograms, lung CT scans (for those at high risk for lung cancer) to lower your risk of dying of cancer.

We have recently learned that we may lower cancer risk through vaccination. For example, vaccination against human papillomavirus (HPV) may be recommended for young boys and girls. Those with human immunodeficiency virus (HIV) can reduce risk with so-called retroviral therapy.

Today, we looked at some of the ways you may reduce your risk of getting cancer. We did not look at drugs, such as tamoxifen, to reduce breast cancer risk for women thought to be at high risk of getting the disease. Long-term, low-dose aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) may lower colon cancer risk but are not generally recommended for those not at high risk for getting the disease.

We should remember that aspirin can increase your risk of bleeding. Finally, the anti-diabetes drug metformin may drop the risk of several cancer forms, at least among those with type 2 diabetes. This drug may lower the risk of colon, rectal, liver, and lung cancers.

Do five simple maneuvers, including not smoking, having a balanced diet, watching your weight, not drinking alcohol to excess, and exercising. You may add up to twelve (for men) to fourteen (for women) years of healthy years to your life. You know what you need to do.

I’m Dr. Michael Hunter.