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Cancer Is a Preventable Disease -- So Why Don't We Prevent It?

Cancer is perhaps the most frightening of all diseases we face. And the thing is, it's very often entirely preventable. If we simply made some different decisions, earlier, many cancers would never happen.
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Cancer is perhaps the most frightening of all diseases we face. And the thing is, it's very often entirely preventable. If we simply made some different decisions, earlier, many cancers would never happen.

That sounds like an audacious statement. Cancer after all, comes "out of the blue" -- we report that it happened "suddenly," that it came "without warning." It is the proverbial bolt of lightning that changes our lives all in one strike. How could we prevent lightning?

But in fact, a newly emerging consensus holds that 90 percent of cancers are rooted in environmental or behavioral causes. That means we have a much larger window for rooting out cancer early -- and what's more, a much wider opportunity to head it off before it ever comes close. The lever for opportunity, though, is us -- we need to act.

When you think about it, that makes absolute sense. Consider smoking, which remains the leading cause of cancer in the US. If every smoker quit right now, today, it'd reduce the number of deaths by 440,000, and the number of cancer cases by about 200,000.

Presto! You've just prevented cancer in 25 to 30 percent of the cases in this country. (Of course that's just a pipe dream, so to speak, but you get the idea.)

And there are more examples. Look at the second leading cause of cancer-related deaths: colon cancer. Simple screening strategies such as colonoscopies and fecal blood tests already turn up nearly 150,000 cases of colon cancers early. Greater diligence could turn up tens of thousands more cases (The US Preventive Service Task Force has specific recommendations for colon cancer screening here). This is preventive medicine in action, saving thousands of lives. Same thing with cervical cancer, where another easy test -- the Pap smear -- has saved thousands of lives.

Of course, screening tests aren't a panacea. Recent news on PSA tests for prostate cancer and mammography for breast cancer demonstrates that screening is only effective when it's deployed judiciously and selectively.

But preventing cancer doesn't always mean taking a test. It can mean much simpler things: like changing our diet. In fact, a brilliant 2008 paper from researchers at the esteemed M.D. Anderson Cancer Center in Houston simply and clearly explains how 30 to 35 percent of all cancer-related deaths are linked to diet (even more than are related to smoking). This includes alcohol consumption, which has been linked to many forms of cancer. And the researchers explain, preventing cancer can mean other seemingly simple actions, like getting less sun. That alone would dramatically cut down on non-melanoma skin cancers, the most common form of cancer, with nearly a million cases a year. As many as 50 percent of Americans who live to age 65 will develop a skin cancer, nearly all of whom could have avoided it had they stayed out of the sun more frequently.

And yes, other environmental factors play a role as well -- exposures to chemicals and radiation are estimated to cause as many as 15 cases of cancer deaths. Reducing the amount of chemicals we're exposed to, and reducing the frequency of radiation we're dosed with via CT scans and other radiography, could significantly decrease many cancers.

But what about genetics? What about the cancers that are directly attributable to our DNA? Well, that's less than 10 percent of cases. That's not to say our genes don't increase our risks for many forms of cancer, but cancers that are essentially caused by genetic factors are few and far between. In most cases, it's the interplay between genes and environment and behavior -- leaving us all sorts of room for evasive action.

As the M.D. Anderson researchers put it: "Cancer is a preventable disease that requires major lifestyle changes....Genes are absolutely not our fate."

So what to make of this? On the one hand, practically speaking, few of us are going to upend our lives and make major lifestyle changes. Are we really going to radically change our diets (no meat, no wine)? Are we really going to swath on sunscreen every time we step outside? Probably not. But on the other hand, this evidence shows that we have all sorts of opportunities in our lives to act -- that we are agents in our lives, not passive actors. We have some control. Our actions have consequences -- and conversely, that means we can also take action.

The truth about cancer is that it's something we have some influence over. But in order to take advantage of that fact, we'll need to act far earlier than we do today. We need to be thinking of the long-term ramifications of our actions.

In many respects, this news should be a source of empowerment. It should gird us for action. It should steel us to take on cancer like we've taken on heart disease -- the number one killer in the US (cancer is the steady number two). After all, we already talk about heart disease in terms of risk, and reducing risk. We take huge amounts of baby aspirin and statins in order to reduce that risk. And it's worked: deaths from heart disease have dropped steeply over the last few decades.

But for some reason, when faced with the same options for cancer, we don't really do much of anything. We don't treat cancer like a preventable disease. And as a result, cancer deaths have stayed pretty much flat. Screening rates are typically low, and effective treatments for prevention are underused. A recent study looked at the drug tamoxofin -- a drug that's proven to cut the risk of breast cancer in half for women at high risk. Alarmingly, though, the study found that an "exceptionally low" number of eligible women actually took the drug. For whatever reason, they weren't compelled to make the smart choice, a choice that could save their lives.

We need to change the way we think about cancer, and we need to change the way we talk about cancer. For too long the conversation -- among scientists, politicians, and the media -- has focused on the idea of a "war" on the disease, spending billions of dollars to find a cure (which, in case you haven't heard, we still don't have). It's been all about end-stage treatments and too little about preventive action.

We need to talk about cancer like we do heart disease. Dr. David Casserett wrote on HuffPost Living recently about how we talk about cancer in the wrong way. We need to change the dialogue. We need to make a few things clear about this disease. We all have a risk. But we can all, likewise, take actions that reduce our risk.

The war on cancer begins at home -- your home and mine.

Thomas Goetz is the executive editor at Wired Magazine and author of the new book The Decision Tree: Taking Control of Our Health In the New Era of Personalized Medicine.