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ASCO: You’re listening to a podcast from Cancer.Net. This cancer information website is produced by the American Society of Clinical Oncology, known as ASCO, the world’s leading professional organization for doctors who care for people with cancer.

The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement. Cancer research discussed in this podcast is ongoing, so the data described here may change as research progresses.

Many people are aware that quitting smoking or other tobacco use will reduce the risk that someone will develop cancer. In today’s podcast, Dr. Noelle LoConte, Dr. Jeffrey Gershenwald, and Dr. Cynthia Thomson will discuss their article from the 2018 ASCO Educational Book, “Lifestyle Modifications and Policy Implications for Primary and Secondary Cancer Prevention: Diet, Exercise, Sun Safety, and Alcohol Reduction,” and share tips for other changes people can make to reduce their cancer risk.

Dr. LoConte is a medical oncologist at the University of Wisconsin Carbone Cancer Center and an Associate Professor of Medicine at the University of Wisconsin School of Medicine and Public Health. Dr. Gershenwald is Professor in the Department of Surgical Oncology at The University of Texas, MD Anderson Cancer Center. Dr. Thomson is a Professor and Director of the Canyon Ranch Center for Prevention and Health Promotion in the Mel and Enid Zuckerman College of Public Health at the University of Arizona.

Published annually, the Educational Book is a collection of articles written by ASCO Annual Meeting speakers and oncology experts. Each volume highlights the most compelling research and developments across the multidisciplinary fields of oncology.

ASCO would like to thank Dr. LoConte, Dr. Gershenwald, and Dr. Thomson for discussing this topic.

Dr. LoConte: Hello, my name is Dr. Noelle LoConte from the Carbone Cancer Center. I’m joined today by Dr. Jeffrey Gershenwald, from The University of Texas MD Anderson Cancer Center, and Dr. Cynthia Thomson from the University of Arizona Cancer Center. In this podcast, we will be sharing some key points from our 2018 ASCO Educational Book article titled, “Lifestyle Modifications and Policy Implications for Primary and Secondary Cancer Prevention: Diet, Exercise, Sun Safety, and Alcohol Reduction.”

Lifestyle behaviors and their impact on a person’s cancer risk have been widely studied by cancer researchers. Experts have found that modifiable behaviors, like diet and exercise, account for between 30 to 50 percent of cancers. And, many reports have found that if Americans followed the cancer prevention recommendations issued by the American Cancer Society, that cancer rates could be reduced by about 17% overall and by up to 60% for some cancers in high-risk groups.

One major driver of cancer risk is obesity. Dr. Thomson, you’ve done quite a bit of work studying obesity and cancer risk. Can you tell us about what you’ve learned?

Dr. Thompson: I’d be happy to, Dr. LoConte. Over the past several decades, rates of obesity have risen to epidemic proportions in the United States, and it is likely that this factor has contributed to higher rates of several cancers in America. Experts estimate that obesity increases cancer risk as much as 20% overall and 50% for people under the age of 65. These findings mean that we need to promote life-long weight management as a way to reduce the rates of cancer. For those who are overweight or obese, losing even a small amount of weight has been shown to have health benefits.

Dr. LoConte: What foods should be avoided to reduce cancer risk and maintain a healthy weight?

Dr. Thompson: Avoiding sugary drinks, processed meats like those we find in the deli, red meat, and refined grain products like white bread, can promote weight control and thus help some people to reduce the risk of cancer.

We should try to eat more of a variety of vegetables, fruits, whole grains, and legumes. Ideally, a person would eat at least 2 and half cups of vegetables every day.  And of course, alcohol consumption should be reduced or eliminated.

Dr. Gershenwald: What are some other ways people can manage their weight?

Dr. Thompson: Controlling the amount of food you eat is the most important step toward weight loss and weight control. But physical activity is another great way to maintain a healthy weight, Dr. Gershenwald. Adults should engage in at least 150 minutes of moderate-intensity activity or 75 minutes of vigorous activity each week. Children and adolescents should engage in at least 1 hour of moderate or vigorous intensity activity each day, with vigorous intensity activity at least 3 times per week.

A good way to tell what level of activity you’re engaging in is the talk test. During a moderate-intensity activity, you should be able to carry on a conversation, but not sing. During a vigorous activity, you should be breathing heavily.

In general, we need to try to limit the amount of time we’re sitting, lying down, watching television, or playing on our phones. These sedentary activities can negatively impact our weight and our health.

Dr. LoConte: Dr. Thomson, you mentioned earlier that alcohol consumption should be reduced or eliminated to help with weight loss, and I wanted to talk a little more about that. We know that alcohol negatively affects a person’s weight, but we are now learning more and more about how alcohol and cancer are related. Head and neck cancer, breast cancer, squamous cell esophageal cancer, liver cancer, and colorectal cancer have all been linked to alcohol.

Dr. Thomson: Is the cancer risk for alcohol consumption dependent on how many drinks a person has per day?

Dr. LoConte: Although risks are highest with moderate and heavy drinking, there is increased cancer risk even among light drinkers. Studies have shown that if someone only has 1 drink per day, they may be putting themselves at an elevated risk for some types of cancer, like breast cancer. For cancer prevention, it’s best not to drink alcohol. The take home point is that the more you drink, and for the longer the period of time, the higher your risk of cancer. As an oncologist, it’s important for me to be honest with my patients about the role of alcohol and cancer. This is really hard because we live in a culture where alcohol use is widely accepted as a norm.

Dr. Gershenwald: What kinds of alcohol are associated with cancer risk?

Dr. LoConte: All kinds, Dr. Gershenwald. Wine, beer, and liquor. In any form, alcohol plays a role in carcinogenesis—meaning it helps cancer grow. A drink is considered to be 5 ounces of wine, 1.5 ounces of distilled spirits, or 12 ounces of 5% beer.

Dr. Thomson: Another behavior that is tough to change, but is critical for cancer prevention, is overexposure to ultraviolet, or UV, radiation. Dr. Gershenwald, this happens to be your area of expertise. Can you tell us more about how UV radiation exposure impacts our risk for cancer?

Dr. Gershenwald: I’d be happy to, Dr. Thomson. UV radiation exposure is a major contributor to risk for and cause of most skin cancers, including melanoma, the most lethal. It is somewhat alarming to hear that nearly 95% of all melanomas arising on the skin, as well as deaths from melanoma in the United States, are attributable to UV radiation. When melanoma is caught in its early stages, it is very treatable and most patients have favorable outcomes. But when melanoma is diagnosed at later stages, it can be highly aggressive and difficult treat.

Dr. LoConte: If such a significant fraction of melanomas are related to UV, is there anything people can do to reduce their risk of cancer due by reducing UV radiation exposure?

Dr. Gershenwald: Absolutely. Using broad-spectrum sunscreen with an SPF of at least 30 and wearing protective clothing–including wide-brimmed hats, long-sleeved shirts, and sunglasses as some examples–can help reduce the harmful effects of ultraviolet radiation when you’re outside. Try not to be outside between 10 AM and 2 PM when the sun’s rays are the strongest, and if you are, try to seek shade.

Sun-protection practices are important for people of all ages, but are especially important for children and teens. Having 5 or more blistering sunburns while young has been estimated to increase a person’s risk of melanoma by about 80%.  Facilitating the use of sunscreens in our schools is also a great way to promote sun safe behavior at a young age.

Dr. LoConte: What about tanning beds? Are they a safe alternative to the sun?

Dr. Gershenwald: No, they are not safe, Dr. LoConte. Tanning beds emit the same kind of UV radiation as the sun. Avoiding tanning beds is important to reduce the risk of skin cancer. Starting indoor tanning before age 18 increases melanoma risk by 85%, and starting between age 18 and 24 increases melanoma risk by about 90%.

Dr. LoConte: Thank you, Dr. Gershenwald. To summarize what we’ve discussed today, there are many known behaviors that can help reduce a person’s risk of cancer, including maintaining a healthy weight, avoiding alcohol consumption, and protecting against ultraviolet radiation. Healthy lifestyle choices promote a cancer-suppressing environment in our organs, tissues, and even at the DNA level, thus increasing the potential together to reduce cancer risk.

I hope you’ve enjoyed our podcast. To learn more, please view our article online at ASCO.org/edbook. Thank you.

ASCO: Thank you Dr. LoConte, Dr. Gershenwald, and Dr. Thomson. Please visit ASCO.org/edbook to read the full article. And if this podcast was useful, please take a minute to subscribe, rate, and review the show on Apple Podcasts or Google Play.

Cancer.Net is supported by ASCO’s Conquer Cancer Foundation, which funds breakthrough research for every type of cancer, helping patients everywhere. To help fund Cancer.Net and programs like it, donate at conquer.org/support.

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