Obesity Could Soon Be the Leading Preventable Cause of Cancer in the United States

By Jennifer Castoro,

Tuesday, January 13, 2015

Pictured: Clifford Hudis

Experts warn that the nation’s weight problem could significantly raise cancer risk — and awareness of the link between the two is lacking.

If you asked people to name the leading preventable cause of cancer in the United States, most would likely say tobacco. And they’d be correct — smoking and use of tobacco products is indeed the number-one culprit. But experts predict that statistic is about to change.

According to a recent policy statement issued by the American Society of Clinical Oncology (ASCO), obesity is poised to overtake tobacco as the leading modifiable cause of cancer in the country in the not-so-distant future. What’s more, the average person isn’t aware that excess weight and cancer risk could even be connected.

“Almost everybody in America, smoker or not, knows that lung cancer is associated with tobacco use,” says Clifford Hudis, a leading researcher on the subject who heads the Memorial Sloan Kettering Breast Medicine Service and recently served as president of ASCO. “Conversely, only about 10 percent of Americans currently know that obesity is associated with cancer.”

Obesity is considered a modifiable risk factor for cancer, which means that people may be able to decrease their risk of developing the disease by addressing the issue — hence why it’s so vital to spread awareness of the link between the two.

And while tobacco consumption is possibly more controlled than ever in the United States, the problem of obesity continues to grow. “Current projections are that 60 percent of the residents of most of the southern states will be obese by 2030,” says Dr. Hudis. “It threatens to undo some of the progress we’ve made to reduce cancer mortality through impressive scientific advances. And we have an opportunity and responsibility right now to try to do something about it.”

Exploring a Complicated Connection

The first actionable step for researchers is to dig more deeply into questions surrounding the obesity-cancer relationship. Dr. Hudis takes care to emphasize that a one-size-fits-all solution like dropping pounds may not be the answer.

“It isn’t as simple as diet,” he says. “It may be that the diet content can be manipulated to some advantage, meaning that everybody who’s overweight won’t have to lose weight. Maybe a modest amount of weight loss, while you still remain obese, is sufficient to reverse a lot of the problems. There are hints about a lot of these things. And so the problem is that we don’t yet know.”

MSK is in a unique position to tackle this problem for several reasons, he adds. “We have the scientific strength to address the basic biology, the clinical resources to study it in many malignancies, and we’re in a neighborhood with real non-cancer expertise that supplements our own.”

In one example of that collaboration, Dr. Hudis and colleagues from Weill Cornell Medical Center, led by Andrew Dannenberg, are currently studying the effects of the chronic inflammation that’s known to be present in the fat tissue of most overweight and obese people to see if there’s an association with the development of cancer.

Despite these clear signs that more research is needed, the issue may lack some support. “Lots of people will say, ‘Well, we know everybody should be lean. We know it’s healthier. Why do we have to study it?’” says Dr. Hudis. “But we have to acknowledge that lots of people can’t lose weight whatever they do, at least in our current environment. …We need to understand what we can do that actually alters the pathologic consequences of obesity, even if we don’t make people svelte.”

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The Benefits of Changing Habits

For people who are obese, there are a myriad of clear reasons to lose weight that go beyond cancer risk — and certainly not everyone who fits the weight criteria will develop the disease. Cancer may be the most feared end result, but “the truth is cancer is still not the dominant health risk of obesity, and it won’t be,” says Dr. Hudis. “The dominant risks will remain hypertension and diabetes and arthritis, and all of the other common diseases that go along with obesity. And of course many people get cancer when they’re lean while many others who are obese don’t.”

“The problem of cancer and weight is part of a broader issue of general health,” he adds. “We really are advocating for healthy lifestyle choices. The cancer problem is yet another important reason to make those choices. But it’s not the only reason.”

The call to action is a positive step that can raise awareness of the issue and, hopefully, change behaviors. “From a scientific point of view, this is an opportunity to understand cancer and use that understanding to improve our overall treatment and prevention,” he says.

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I am curious about the link between alcohol consumption and Young-Onset Colorectal Cancer.

Is it a serious risk factor?

Marcia, thank you for reaching out. There actually is still very limited information on risk factors such as alcohol consumption for early age onset colorectal cancers.

You might try calling the National Cancer Institute’s Cancer Information Service at 800-4CANCER (800-422-6237). To learn more about the CIS, including Live Chat help and how to send them an email message, go to http://www.cancer.gov/aboutnci/cis/page3.

Totally agree that obesity is very controllable by many different methods, and as a result the litany of diseases that come as a result of it.

Do you have a weight loss program?

Kay, we do not have a general weight-loss program, but we do offer resources to help people lead healthier lifestyles. These include:
-consultations with nutritionists-dieticians

-educational materials on eating healthy during and after cancer treatment

-exercise classes and workshops

Thanks so much for your question!

I used to be a medical writer and from what I infer chronic inflammation seems to be the culprit in a host of health problems including cancer. Maybe the most serious. Is there a test to measure one's level of inflammation and how can one reduce it besides losing weight and exercising?

Bess, we sent your question to Dr. Hudis, and he responded, "We are exploring indicators of inflammation that might be useful in this situation but there is no routine test for this purpose today. In addition to exercise and weight management, it is possible -- but not established -- that some dietary components may raise or lower the kind of adipose inflammation our group is studying. But we do not yet have evidence-based specific recommendations." Thank you for your comment.

Whenever I read articles citing smoking or obesity as top causes of cancer, I feel frustrated. I am a thin woman who has never smoked, rarely has a glass of wine, and has no family history of cancer, yet I have kidney cancer. These articles seem to blame people for causing their cancer when sometimes it's totally random.

Cindy, thank you for your comment. We agree many cancers occur simply because of random chance--this was actually discussed in a recent New York Times story, which quotes one of our doctors:


At the same time, its important for people to be mindful of lifestyle factors (such as smoking and diet) because evidence suggests that up to 50 percent of cancers may be preventable.

In addition, a small percentage of cancers (5 to 10 percent) are thought to be largely due to inherited mutations.

Any connection between the immune system and inflammation?
Peoples hormones change with age, weight becomes harder to loose (any connection to cancer). Has any research been done on people with Prader Willy
Syndrome and cacer risk? Can this weight and increased cancer be genetics?

Lisa, we sent your questions to Dr. Hudis. In response to the first question, he said that immune components do play a role in inflammation. In response to the second part, he said, "There are many components to an individual's risk of cancer, including genetics and diet." Thank you for your comment.

Do the children of cancer survivors have a greater risk of cancer?

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