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Clinical Practice Statements for the Management of ObesityCancer and Obesity - Part 1

Learning Objectives
1. Describe the complex relationship between cancer and obesity
2. Explain how the decline of nicotine use over the past 30 years can inform physicians regarding possibilities for obesity management and care
3. Discuss the nature of fat as a metabolically, hormonally active substance that predisposes the body to different types of cancer
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Audio Transcript

Intro: Welcome to Obesity: A Disease, the official Obesity Medicine Association podcast exploring the many facets of the disease of obesity. In this episode, OMA Chief Science Officer, Dr Harold Bayes interviews Dr Ethan Lazarus, the current president of the Obesity Medicine Association.

Today, our guests discuss the complex relationship between cancer. Topics include the widespread lack of awareness of obesity as a major driver of both cancer and heart disease. Have the steep decline of nicotine use over the past 30 years can inform us regarding possibilities for obesity Management Today and the true nature of fat as a metabolically hormonally active substance that predisposes the body to different types of cancer. Additionally, our experts discuss the management and care of patients with obesity following a cancer diagnosis as well as the need for aggressive treatment of obesity using behavioral, medical, and surgical strategies. This podcast is presented in two parts. Today we hear the full podcast. Obesity: A Disease podcast is brought to you by the Obesity Medicine Association, a clinical leader in obesity medicine.

Harold Bays, MD: My name is Dr Harold Bayes, medical director and president of the Louisville Metabolic and Atherosclerosis Research Center, located in Louisville, KY. I'm also chief science officer of the Obesity Medicine Association. Welcome to this program today entitled Obesity: A Disease. This is a periodic podcast that's sponsored by the Obesity Medicine Association and today we're going to be talking about a clinical practice statement that was issued by the Obesity Medicine Association and it's entitled Cancer and Obesity. And we're just fortunate to have with us today, Dr Ethan Lazarus, who is the first author on this paper. Dr Lazarus, can you tell the folks who you are and what you do?

Ethan Lazarus, MD: Hi Harold, thank you so much and what a pleasure it is to be on the podcast. My name is Ethan Lazarus and I've been an obesity medicine physician now for nearly 20 years. I run a practice in Greenwood Village, Colorado, where we specialize in a team approach to the chronic treatment of obesity, including physician assistant, registered dietitian nutritionists. And we're skilled at using all the various anti-obesity medications, behavioral strategies and that sort of thing. Also had the pleasure of being a member of the Obesity Medicine Association. For nearly 20 years I've been on their board and currently serve as the President of the OTC Medicine Association. I also represent the Obesity Medicine Association as their delegate in the American Medical Association trying to bring the priority of obesity forward for our whole medical system here in America so again, thanks for the inviting me for the podcast and I look forward to talking about cancer.

Bays: Right, uh, so this is just so perfect that you would be the one that that we would have to talk about this here today because I'm not sure that many people are aware of this intimate relationship between the obesity and the cancer. I mean, I think a lot of people know about sleep apnea and they know about orthopedic problems and they. They know about cardiovascular disease, but I'm not so sure everybody has a good bead on this relationship. Between obesity and cancer, and I think just as a just as a start, I think it's important to emphasize that if you look at the epidemiology of cancer, it's estimated that over 90% of cancer, not due to genetics, but due to the environment. And if you look at specific. What they call what is called population attributable fractions. We find that we know about. We have a pretty good understanding about 50% of the case. And it's been estimated that about 19% of cancers are due to cigarette smoking. About 8% is due to excess body weight. But what's also interesting is that there are a lot of other things that sometimes go with the obesity, which are things like physical inactivity and. Low fruit and. Vegetable intake and low fiber consumption and the consumption of processed meats and red meat consumption and low calcium intake. These all also increase the risk for cancer, so if you add them all up together it should be no surprise that. That yes, I think we would still say that cigarette smoking is the most common preventable cause of cancer. But obesity is not far behind for non-smokers. One could say that as far as an identical identifiable cause, obesity's right there at the top of the list of potential causes.

So, Dr Lazarus. I'd just like that ask you this question. You know when you when you have these movies and you have these TV shows and the black and white TV shows, you see all these programs. Everybody was smoking back. Then there was so much cigarette smoking and not all that many people had the overweight and obesity. And nowadays I don't even think you can put cigarette smoking on the TV, I think that's, that's banned. I mean, you certainly don't see it very often, but yet we certainly in our practices and in our daily lives see many patients with overweight and obesity. Can you give us a sense about, what is the relative prevalence of the cigarette smoking and obesity? I mean what's going on there? It seems like there's been a change.

Lazarus: Yeah, and it's been very interesting to watch during the course of my medical career because I went through medical school in the 90s and back in those days. It's about all we talked about was smoking and trying to find strategies to help people smoking, and it's estimated back then that around 42% of Americans were smoking. And thanks to, I think the efforts of our health system, our American Medical Association, public education physician, education of their patients, new pharmacotherapy, treatments, making it difficult to smoke. So you can't just, you know, smoke in the front half of the airplane and then the back half of the airplane was the non-smoking. So making it so you couldn't smoke in restaurants, couldn't smoke on airplanes, and what we've seen is the prevalence of smoking has gone from 42% back then down to 15% today. Now of course the flip side is back. In those days we didn't talk a lot about obesity. It wasn't that common. There weren't that many heavy folks. It's estimated back in those days that only around 13% of Americans have the disease of obesity and this is completely flip-flopped. Where today it's estimated that 42% of Americans have the disease of obesity. So it's certainly my opinion that we've got our work to do so that the obesity doesn't keep spiraling out of control and driving up health care costs and leading to more and more problems. And I'm certainly hopeful that through education, both the public and the health care system, we can do for obesity the same successful types of strategies that we were able to implement for helping Americans overcome nicotine.

Bays: Look, that is so important and I really need to follow up on that. You know, Ethan, so many times we hear people, they're discouraged. There's…a lot of times as individuals, there's sort of a defeatism and among clinicians, there's sort of a sadness, a sort of a sense that there's really…that it's really hard to make an impact upon obesity, but I'll bet that back in the day people said the same thing about cigarette smoke. And yet to the very initiatives that you talked about right there with the American Medical Association and strategies that were implemented, I mean, it really didn't matter and it made a difference. I mean, I know a lot of times people say, well, government really can't help or private sector really can't help, but, I don't think that's true. I mean, I think there's as much an opportunity to make a huge difference by innovation and intervention and just thoughtful approaches to again, the public sector and the private sector and such that we can make a difference. I mean, am I being too optimistic? I mean, what do you think?

Lazarus: No, I mean, you can definitely draw a lot of parallels, and I mean I'd be curious. I don't know the statistic for the number of people that die from cigarette related cancers these days, but I'd imagine that that with the prevalence of smoking going from 42% to 15%, we've made a huge impact. Things like taxing cigarettes, things like making it not allowable to smoke in most public venues, things like warning labels on cigarettes. I think all of these initiatives were difficult to implement and there was a lot of pushback. I remember restaurants were worried they could go out of business if they wouldn't allow people to smoke in the restaurant, and so on, and so on. But at the end of the day, these things did work, so we certainly had a precipice with obesity where we can learn from our success in nicotine. And I think we could apply what we've learned to obesity and make a real difference.

Bays: And look, for all for all those people out there that think this is government oppression or whatever, look—to my fellow libertarians out there, a lot of what I think that was done that was effective is education, and there's nothing oppressive about informing patients. And people were informed about the dangers of cigarette smoking and I think that there's…the analogy there would be to get people educated about appropriate nutrition, and get people educated about physical activity. and get people educated about this connection with obesity to not just diabetes, hypertension, dyslipidemia, heart disease, but also the topic we're talking about today, which is cancer. I mean, what's your sense about the potential of just education alone in improving the lives and the health of patients with obesity?

Lazarus: Yeah, I think that's a great question. I you know I was. I was reading the other day. I was curious in terms of how many Americans actually die from cancer every year. And looking at the CDC website, it's roughly 602 000 Americans dying annually of cancer, which isn't that far behind heart disease, which is of course the number one cause of almost 700 000 deaths. But I don't think a lot of people recognize that obesity is a major driver of cancer, and let alone heart disease. A lot of people think that, you know, cancer just happens, that it's bad luck, and don't necessarily realize there's a lot of things that we're doing that can put us at risk for cancer.

You know, for example, people understand the value of staying out of the sun and using sunscreen to prevent melanoma. People understand the value of not smoking to prevent lung cancer. People might even understand the benefit, for example, of getting vaccinated for hepatitis or vaccinated for HPV to prevent liver cancer and cervical cancer, but I don't think a lot of people realize that fat—it's not this metabolically inert substance that just sits there and pads the body. The fat is actually very active metabolically and hormonally and it's actually making our body far more prone to developing multiple types of cancer, and that by carrying all the extra weight, unfortunately we're pouring gas on the cancer epidemic. And so I know we'll talk about it as we go forward, but reducing the body fat mass can have profound benefits for reducing cancer risk, much like if you have a person who's a smoker and you help them quit smoking, over time their risk for lung cancer gradually gets lower and lower.

Bays: So, so let's get into it. I know there's a lot of listeners out there that're saying, OK, you say that obesity contributes to cancer, but what's the mechanism? How does that happen? Well, I think you've already answered the question. The fact is that adipose tissue and the fat cells are very active from an immune standpoint, and from an endocrine standpoint with regard to hormone production and such. And what happens is when the fat cells become enlarged, the adipose tissue expands with the obesity. You get this adiposepathic cytokine production. It's increasing these cytokines which contributes to cancer. You get relative hypoxia so that so you're outgrowing the vascular supply, so you get this relative toxin, which increases the risk of cancer. You have an increase in oxidative stress. You alter the tumor microenvironment. You have these cancer-promoting hormones that are produced which increase the risk of cancer. And then you have unhealthful nutrition and physical inactivity and such. I mean just as a you know, one example just showing the analogy between cigarette smoking and obesity, with both of these, you have an increase in what we call reactive oxygen species, which I think many people know contribute to aging and fibrosis and DNA damage, but also increases the risk of cancer.

So, so I think just that brief description alone, I think we can understand why it is that when you do get an increased risk of cancer, what kind of cancers are they going to be? Well, by and large, with a few exceptions, it's going to be cancers of the gastrointestinal system, cancers of the genital urinary system, and cancer of sex hormone-sensitive tissues. And why is that? Because as I mentioned before, when you have an increase in fat cells or an increase in the adipose tissue organ, you have disruption of all these hormones and such and many of them predispose to cancer. So for the listener out there, that's saying, OK, you've given me, you've given me a lot of categories there. You've given me an overview, but I want to know from my patient, uh, what is that accepted list that's out there that maybe people talk about most about the types of cancers that are most related or most attributable to the obesity? Do we have such lists?

Lazarus: Yeah, sure, and thanks for asking that, Harold. So again, it's going to be your female cancer, so breast cancer, particularly postmenopausal, of course ovarian cancer, and uterine cancer as well. It's going to be gastrointestinal cancers including colon and rectal cancer, esophageal cancer, gallbladder cancer, liver cancer, pancreas and stomach cancer, and then in addition to that kidney cancer meningioma, multiple myeloma, and thyroid cancer, I believe I named all 13 cancers. And you know these are real cancers that we clinicians see in our practices unfortunately on a daily, on a weekly basis. I was heartbroken just. A few weeks. Ago one of my patients. Unfortunately, it contracted gallbladder cancer and eleven months later passed away at the age of 59. Somebody I've known a long time and we all know patients that have suffered with all of these types of cancers and the idea that we might be able to prevent these cancers and prevent the morbidity and mortality that patients are suffering every day, I think is very promising and gives us a reason to really light that fire to help us help our patients find effective strategies to get weight off.

Bays: Ethan, I would just like for you to just give a, just a, you know summary here at the end. The folks listening to this program maybe weren't aware of this intimate relationship between the obesity and the cancer—from your experience as a clinician, and certainly from your experience as president of the Obesity Medicine Association, what sort of practical advice or guidance could you give to the clinicians out there with specific regard to the obesity and cancer?

Lazarus: Yeah, so patients come in all the time and they're sharing with their health care provider that they have a sister or a mom that had breast cancer, and they're concerned about their risk. And it really opens up the door for the health care provider to talk about the patient's weight in a positive way and to let the patient know that you understand that that's a concern for them and there's something we can work on today to help them lower their cancer risk. But that the patient might not really have insight that their body mass index is really causing them risk for all these other things and that it's treatable and we can do something about it. I find that when we talk to the patient about their obesity as a disease like hypertension or diabetes or cancer, if you'd like, that patients warm up to the idea that it can be treated, it can be treated successfully. So we can really use this to tell people, look you can lower your risk of dying from cancer by 42%, 43% if we treat your weight and treat it seriously. So let's give you all the tools to do the best job with your weight that we can so we can lower your risk and improve your quality of life as much as possible.

Bays: And look, you know, maybe your experience is different than mine, but it's been my experience that you tell somebody that you want to engage in cardiovascular risk prevention, they will listen. They will listen, but if you tell somebody you can reduce their risk of cancer, they're really going to listen. Has that been your experience?

Lazarus: Oh yeah, I think that's absolutely true. A lot of people view heart disease as something that just happens as a result of aging, but there's definitely a fear factor with cancer. And so telling patients strategies where they could lower their cancer risk, I think it's very compelling to help them get motivated and to get to work with you on getting as healthy as they can.

Bays: Well, there you go. I think that's an outstanding summary. So Dr Lazarus, thank you so much. This has been. I think it's been an amazing program about a topic I don't think people talk about enough, and hopefully we've just given people just a glace of the kind of information that's out there. And again, this is all derived from the clinical practice statement put out by the Obesity Medicine Association. Dr Ethan Lazarus is the lead author on the paper and I want to thank you for, I think, just an outstanding program and I want to thank you the listeners for attending this podcast sponsored by the Obesity Medicine Association. My name is Dr Harold Bayes and you've been listening to Obesity: A Disease.

Outro: Thank you for listening to this episode of Obesity: A Disease. For more information about Obesity Medicine podcasts and other valuable resources from the clinical leaders in obesity medicine, please visit www.obesitymedicine.org\podcast. If you enjoyed this episode and want to listen regularly, head over to iTunes where you can subscribe, rate, and leave us a much appreciated review. The views expressed in this episode are those of the host and guests, and do not necessarily represent the opinions, beliefs, or policies of the Obesity Medicine Association or its members. Please join us again for our next episode of Obesity: A Disease.

Audio Information

© 2022 Obesity Medicine Association. All Rights Reserved.

Disclosure Statement: Unless noted, all individuals in control of content reported no relevant financial relationships.

If applicable, all relevant financial relationships have been mitigated.


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