Reality Check on Cancer: Fast Progress But Too Many Preventable Deaths

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The latest status report from the American Association for Cancer Research (AACR) shows that most cancer deaths are avoidable.

Compared to 1990, one million fewer people died of cancer and the number of cancer survivors – currently at 13.7 million in the U.S., continues to climb.

That’s due to new drugs that are finally reaching the market after decades of research and development, according to researchers at the AACR. In the past year, 11 new drugs were approved by the Food and Drug Administration to treat cancer; eight of them belong to a class of medications known as targeted therapies that are designed specifically to attack genetic mutations in tumor cells and block their ability to grow. “We are finally seeing the payoff of investments over the past ten to 30 years that built up a body of knowledge about the underpinnings and root causes of cancer,” says Dr. Charles Sawyers, president of AACR and chair of human oncology and pathogenesis at Memorial Sloan Kettering Cancer Center.

But while cancer care if becoming more sophisticated and personalized, deaths from preventable disease continue to plague not just the U.S. but populations worldwide. Half of all cancer deaths are avoidable by reducing exposure to the sun, quitting smoking and maintaining a healthy weight. One third of cancer deaths in the U.S. is caused by tobacco, and another third are associated with obesity, a still emerging risk factor for cancer that much of the public has yet to appreciate.

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“I’m not sure how much the link between obesity and cancer has penetrated the public awareness,” says Dr. Cy Stein, deputy director of the comprehensive cancer center at the City of Hope Medical Center. “If we could eliminate that, another 20% to 30% of cancer deaths could be eliminated.”

In recent years, studies have linked obesity to a higher risk of developing esophageal, colorectal, endometrial, kidney, pancreatic and breast cancers. Hormonal changes, as well as agents released by fat tissue can create fertile conditions for inflammation, a process that accelerates the cancer process.

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In addition to educating people about the most effective ways to prevent cancer from developing in the first place, improving screening methods to detect the first signs of tumors can also reduce risk of disease significantly. But this effort may require more attention in coming years as more refined guidelines for who should be screened, and when, to achieve maximum benefit for the entire population are released. As experts shift from broader, one-size-fits-all approaches to diagnosing and treating the disease – such as the strategy for always removing or treating every lesion – the public will also have to shift its understanding that not everyone needs to be screened regularly, and that not every tumor necessarily needs to be treated.

In recent years, revised guidelines that healthy men with no significant risk factors for prostate cancer do not need to get regular prostate specific antigen (PSA) blood tests, for example, and that women should wait until they are 50 for routine mammograms, have confused some people – and even doctors. “One of the big lessons we learned over the last 20 years is how individualized cancer is,” says Stein. “The way I like to view cancer is like a great tree. What you see first is the big massive trunk that looks the same in all dimensions. But as you look upward, it arborizes into branches, and thinner and thinner branches until to get to the leaves. And that’s where the details are, in the leaves.”

There will still be some general principles that apply to most cases when it comes to understanding what drives tumors and how best to slow them down, but increasingly, it may take more personalized strategies for helping patients to control the cancer that is unique to them. “There are so many interventions now, because there are so many different forms of cancer,” says Stein. “That’s why this is an exciting time to be a medical oncologist.”

2 comments
RichardP.Walczak
RichardP.Walczak

The article states that people who are obese are at a higher risk of developing cancer(s).  Is it obesity per se, or is it what obese people consume?  Any facts relative to that?

guest_scientist
guest_scientist

@RichardP.Walczak As a cancer research scientist, I can weigh in on some of the connections between cancer and obesity. From what I have read and tested in the lab, it appears that obesity initiates inflammatory pathways in a seemingly noninflammatory setting. The inappropriate inflammatory response starts a chain of reactions in cell pathways that try to adapt to the inflammatory signals. Homeostasis requires reset of inflammatory signaling pathways, but in the ongoing presence of inflammatory type signaling, cells must change their gene expression to deal with the upset in homeostasis or risk cell death. Many cells "choose" to die (apoptosis) while others die by necrosis, a very messy, inflammatory-promoting process. Some cells adapt by promoting cell viability and growth in the background of stressful cellular conditions. This adaptation is selected for and contributes to the transformation of normal cells to cancer cells.