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.”Back to top
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.Back to top