Obesity and Cancer
From the Show: Highland Medical P.C.
Summary:
Air Date: 4/5/19
Duration: 10 Minutes
Dr. Marc Zimmerman discusses the link between obesity and cancer.
Transcription:
Deborah Howell (Host): The link between obesity and cancer risk is clear. Research shows that excess body fat increases your risk for several cancers. What’s less clear, is exactly how being obese increases that risk. I’m Deborah Howell and in this episode of The Highland Medical P. C. Podcast series, we’re going to be talking about obesity and cancer. Here with us today is Dr. Marc S. Zimmerman. He’s an oncologist and hematologist at Highland Medical P.C. Dr. Zimmerman, thank you so much for being with us today.
Marc S. Zimmerman, MD (Guest): You’re very welcome.
Host: All right. Let’s get into it. How are obesity and cancer related?
Dr. Zimmerman: Well I think most of us recognize that obesity is an unfortunate epidemic, not only in our country but in just about every country in the world. Most of the definitions would include those persons with a body mass index of greater than 30. This is a formula that takes into account height and weight and by current estimates, right now, that applies to at least one third of the population.
We know about the increased risk in hypertension and heart disease, but I think many of my patients and patients in general, don’t have that same sense for obesity as a risk for cancer. What we do know about obesity and it’s role in certain diseases, is that first of all, it is considered a chronic inflammatory condition, and this certainly plays a role in its link to heart disease. That may be an issue in certain types of cancer. But I think it’s a little bit more complicated than that.
We are starting to understand what that risk is. There is certainly a risk in a number of cancers associated with increased levels of estrogen hormones and that’s because the fat cells that are more common in obese patients actually convert non-estrogen type of hormones into estrogen and we know that estrogen is a risk factor for example in breast cancer and uterine cancer.
There also is an association with type 2 diabetes which has become more and more of a problem. And the link there appears to be with the increased insulin production that we see in patients with this type of diabetes and the accompanying resistance to insulin. So the resistance to the effect of insulin increases the amount of insulin produced and insulin we know is a growth factor and it is a growth factor that is likely important in many types of cancer.
Host: Earlier you mentioned inflammation. What is inflammation and how does obesity cause inflammation?
Dr. Zimmerman: I don’t think we know the exact link. Inflammation one can think of as irritation, but irritation in the sense that certain inflammatory cells and inflammatory factors in the blood are increased by obesity and may have an effect for example on the walls of blood vessels in patients with heart disease.
Host: Got it. Now what specific types of cancers can result from obesity?
Dr. Zimmerman: Well I don’t think we can say that there that any cancer would be caused by obesity and no other factor, but we can say that the relative risk of cancer of various kinds is increased in obese patients. So, for example, in colon cancer, we are seeing a very unfortunate trend in the diagnosis of colon cancer where patients are being diagnosed at younger ages. Normally, we have the recommendation for first colonoscopy at age 50 but we are seeing patients diagnosed in their late 30s and 40s and we know that a weight gain between adulthood and midlife increases the risk of colon cancer by about 20-30%. This is also linked to diabetes and again, may be one of those cancers that is linked to the insulin resistance.
Breast cancer. Breast cancer only in women after the age of menopause and that’s because those are the tumors that are most sensitive to estrogen and for the reasons we described above, obese patients may have increased amounts of circulating estrogens that would stimulate the breast tissue.
In a similar fashion, the cancers of the endometrium or the lining of the uterus are associated with an increasing BMI and we are seeing cancers at a younger age but for example, for a BMI between 25 and 30, that risk of endometrial cancer is about one and a half times the nonobese risk. And for women who are quite obese up to a BMI of 40, that risk may be as high as seven times. This is probably also linked to estrogen levels.
An unrelated type of cancer. We are starting to believe that certain types of primary cancers of the liver may be related to obesity. The link appears to be what we commonly call fatty liver which does produce chronic inflammation within the liver. That inflammation in turn can lead to scarring which is called cirrhosis and cirrhosis is a factor in the development of primary liver cancer. So, we have three very strongly linked types of cancers.
We also are seeing however in patients who develop pancreatic cancer. Pancreatic cancer unfortunately is one of the fastest growing in terms of incidence of cancer that we have. We are starting to see patients diagnosed at a younger age and this too seems to be linked to obesity and indirectly to a decrease in physical activity which often goes along with obesity.
Host: Sure. Not a good trend. Now you’re in the business of helping people so, Dr. Zimmerman, what are some steps people can take right now, I mean today to reduce the risk of obesity related cancers?
Dr. Zimmerman: Well it’s always easy advice to give and harder advice to follow. But we know that obesity in general and dietary factors are very important in our health outcomes not just in terms of cancer but in terms of heart disease, stroke and whatever.
We all have genetic factors over which we have no control but the factors over which we do have control such as what we eat, how much we eat, whether we smoke, whether we exercise. Those are the things that really need to be worked on. I think for all of us. There’s no magic in the treatment of obesity and prevention.
For most patients, it’s a matter of balance between calorie intake and what they burn. And we all burn calories at different rates but most of us as Americans eat more than we need to and certainly more than we should. So combining that dietary change with increase in physical activity and I would say that several of the cancers that I mentioned, and I think I specifically spoke about pancreatic cancer, but in colon cancer, also; there’s seems to be a link between decreasing risk associated with 30 minutes of exercise three times a week.
Host: And it doesn’t even have to be rigorous exercise, right, maybe even just walking?
Dr. Zimmerman: Even walking. Even walking. You’re absolutely right.
Host: Well I thank you so much Dr. Zimmerman for educating us on obesity and cancer. We are all going to get out there and start walking immediately. For more information please visit www.highlandmedicalpc.com. This is Highland Medical P.C. Podcast Series. I’m Deborah Howell. Thank you so much for listening.
Deborah Howell (Host): The link between obesity and cancer risk is clear. Research shows that excess body fat increases your risk for several cancers. What’s less clear, is exactly how being obese increases that risk. I’m Deborah Howell and in this episode of The Highland Medical P. C. Podcast series, we’re going to be talking about obesity and cancer. Here with us today is Dr. Marc S. Zimmerman. He’s an oncologist and hematologist at Highland Medical P.C. Dr. Zimmerman, thank you so much for being with us today.
Marc S. Zimmerman, MD (Guest): You’re very welcome.
Host: All right. Let’s get into it. How are obesity and cancer related?
Dr. Zimmerman: Well I think most of us recognize that obesity is an unfortunate epidemic, not only in our country but in just about every country in the world. Most of the definitions would include those persons with a body mass index of greater than 30. This is a formula that takes into account height and weight and by current estimates, right now, that applies to at least one third of the population.
We know about the increased risk in hypertension and heart disease, but I think many of my patients and patients in general, don’t have that same sense for obesity as a risk for cancer. What we do know about obesity and it’s role in certain diseases, is that first of all, it is considered a chronic inflammatory condition, and this certainly plays a role in its link to heart disease. That may be an issue in certain types of cancer. But I think it’s a little bit more complicated than that.
We are starting to understand what that risk is. There is certainly a risk in a number of cancers associated with increased levels of estrogen hormones and that’s because the fat cells that are more common in obese patients actually convert non-estrogen type of hormones into estrogen and we know that estrogen is a risk factor for example in breast cancer and uterine cancer.
There also is an association with type 2 diabetes which has become more and more of a problem. And the link there appears to be with the increased insulin production that we see in patients with this type of diabetes and the accompanying resistance to insulin. So the resistance to the effect of insulin increases the amount of insulin produced and insulin we know is a growth factor and it is a growth factor that is likely important in many types of cancer.
Host: Earlier you mentioned inflammation. What is inflammation and how does obesity cause inflammation?
Dr. Zimmerman: I don’t think we know the exact link. Inflammation one can think of as irritation, but irritation in the sense that certain inflammatory cells and inflammatory factors in the blood are increased by obesity and may have an effect for example on the walls of blood vessels in patients with heart disease.
Host: Got it. Now what specific types of cancers can result from obesity?
Dr. Zimmerman: Well I don’t think we can say that there that any cancer would be caused by obesity and no other factor, but we can say that the relative risk of cancer of various kinds is increased in obese patients. So, for example, in colon cancer, we are seeing a very unfortunate trend in the diagnosis of colon cancer where patients are being diagnosed at younger ages. Normally, we have the recommendation for first colonoscopy at age 50 but we are seeing patients diagnosed in their late 30s and 40s and we know that a weight gain between adulthood and midlife increases the risk of colon cancer by about 20-30%. This is also linked to diabetes and again, may be one of those cancers that is linked to the insulin resistance.
Breast cancer. Breast cancer only in women after the age of menopause and that’s because those are the tumors that are most sensitive to estrogen and for the reasons we described above, obese patients may have increased amounts of circulating estrogens that would stimulate the breast tissue.
In a similar fashion, the cancers of the endometrium or the lining of the uterus are associated with an increasing BMI and we are seeing cancers at a younger age but for example, for a BMI between 25 and 30, that risk of endometrial cancer is about one and a half times the nonobese risk. And for women who are quite obese up to a BMI of 40, that risk may be as high as seven times. This is probably also linked to estrogen levels.
An unrelated type of cancer. We are starting to believe that certain types of primary cancers of the liver may be related to obesity. The link appears to be what we commonly call fatty liver which does produce chronic inflammation within the liver. That inflammation in turn can lead to scarring which is called cirrhosis and cirrhosis is a factor in the development of primary liver cancer. So, we have three very strongly linked types of cancers.
We also are seeing however in patients who develop pancreatic cancer. Pancreatic cancer unfortunately is one of the fastest growing in terms of incidence of cancer that we have. We are starting to see patients diagnosed at a younger age and this too seems to be linked to obesity and indirectly to a decrease in physical activity which often goes along with obesity.
Host: Sure. Not a good trend. Now you’re in the business of helping people so, Dr. Zimmerman, what are some steps people can take right now, I mean today to reduce the risk of obesity related cancers?
Dr. Zimmerman: Well it’s always easy advice to give and harder advice to follow. But we know that obesity in general and dietary factors are very important in our health outcomes not just in terms of cancer but in terms of heart disease, stroke and whatever.
We all have genetic factors over which we have no control but the factors over which we do have control such as what we eat, how much we eat, whether we smoke, whether we exercise. Those are the things that really need to be worked on. I think for all of us. There’s no magic in the treatment of obesity and prevention.
For most patients, it’s a matter of balance between calorie intake and what they burn. And we all burn calories at different rates but most of us as Americans eat more than we need to and certainly more than we should. So combining that dietary change with increase in physical activity and I would say that several of the cancers that I mentioned, and I think I specifically spoke about pancreatic cancer, but in colon cancer, also; there’s seems to be a link between decreasing risk associated with 30 minutes of exercise three times a week.
Host: And it doesn’t even have to be rigorous exercise, right, maybe even just walking?
Dr. Zimmerman: Even walking. Even walking. You’re absolutely right.
Host: Well I thank you so much Dr. Zimmerman for educating us on obesity and cancer. We are all going to get out there and start walking immediately. For more information please visit www.highlandmedicalpc.com. This is Highland Medical P.C. Podcast Series. I’m Deborah Howell. Thank you so much for listening.
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