Cancer seems to be heading in a new direction. This isn't due, in large part, to declining rates, which tend to be modest. Last week, the Centers for Disease Control issued a report noting that overall rates had dropped in the U.S. for the fourth straight year, but the decrease hovers at around 1.5 percent annually. The real news in the report was that two-thirds of cancers may be preventable. That number divides about equally between cancers due to smoking (the overwhelming cause of lung cancer) and cancers linked to obesity and lack of exercise (linked to cancer of the uterus, colon, kidney, pancreas, and breast cancer in post-menopausal women). Only the remaining one-third are linked to genetic mutations from all other causes, including toxins, radiation, environmental influences, etc.
Any physician trained, as I was, to think of cancer as unpreventable -- aside from smoking, radiation exposure, and chemical toxins like pesticides -- has to be startled by this drastic turnaround. A report from the MD Anderson Cancer Center in Houston went so far as to consider 90 to 95 percent of cancers preventable. Needless to say prevention, which means positive lifestyle changes, is immeasurably cheaper than cancer drugs and surgery. Aspects of common health that annoy people now are proving more critical.
For example, serious attention is now going to "belly fat," which triggers hormones like insulin and estrogen as well as inflammatory compounds throughout the body: These substances enter the cells and apparently lead to distorted processes that can become cancerous. The fat we carry around our midsection isn't passive or benign. It could be a major culprit.
Add to these three studies on aspirin cited recently in an article in The Lancet, the leading British medical journal. Aspirin, a well-known anti-inflammatory, has been linked in three studies from 2012 with preventing many types of cancer. Taking a low (75-300 mg) daily dose of the drug appeared to cut the total number of cancer cases by about a quarter after only three years. (Previously, the benefit was thought to need ten years of a daily dose of aspirin.) In addition, taking aspirin reduced the risk even further, by 37 percent, after five years, with the risk of dying from cancer being reduced by 15 percent. Researchers cannot say that the connection is strong enough to warrant everyone turning to aspiring as a preventive -- there are side effects for some people, such as bleeding of the stomach. It also appears that aspirin treats cancer. Low-dose aspirin reduced the likelihood that cancers, particularly bowel, would spread (metastasize) to other parts of the body, and by as much as half in some instances. In absolute numbers, this could mean for every five patients treated with aspirin one metastatic cancer would be prevented, the researchers estimate.
Another theme of prevention homes in on inflammation, which has already been linked to heart disease. Inflammation is a normal part of your body's immune system response to injury. Problems arise when that inflammation becomes chronic. When that happens, levels of many potent inflammatory chemicals go up. These substances include cytokines (including TNF, IL-1, and IL-6), enzymes (such as COX-2 and 5-LOX), and adhesion molecules. All of these various chemicals have been linked to the development of cancerous tumors, and chronic inflammation precedes tumor growth in most types of cancer.
On the whole, what we're seeing is a pile-up of evidence that reinforces familiar health warnings. It's not news that a healthy lifestyle is desirable. Reducing fat, avoiding red meats, managing stress, and making time for exercise and meditation are the key measures, along with looking toward psychological issues like depression and anxiety. The main difference, as I see it, is that we are moving closer to the long-sought goal of holistic medicine, to treat body and mind as a single dynamic system. This goal runs contrary to the overwhelming trend towards specialization, which streams medical students into becoming experts at isolated parts of the body, such as the brain, liver, kidney, and heart.
The irony is that as medicine becomes ever more intricate, technological, and narrow in its focus, the body continues to operate as a whole. Inflammation, for example, can be induced through dozens of means, from getting a cold to bruising your arm, cutting yourself with a kitchen knife, hitting your head in a fall, or losing your temper. The body holds the inflammatory response in reserve for many situations, and it's a mystery as to when the response is good (inflammation is necessary in healing as increased blood flow rushes to the site of an infection) or bad (inflammation can kill burn victims or injure the brain during high fever).
The theme of prevention has not been this strongly urged since the campaign to end cigarette smoking as a cause of lung cancer began almost 50 years ago. Cancer has been sidetracked by other, more powerful themes. Since genetic mutations are observed in malignant and anomalous cells, there's been a tremendous focus on genetic treatments. These have proven very productive among childhood cancers because when a patient is in childhood, a drug can be targeted at relatively simple and often inherited genetic problems. In adults, whose cancers are far more complicated at the genetic level, such treatments have lagged.
There has also been a crusade for early detection, and here again the results are decidedly mixed. What matters to a statistician is the age at which people die of cancer. About 50 years ago a woman may have been diagnosed with a lump in her breast and died two years later at age 62. Now with early detection, she may be diagnosed with a few anomalous cells at age 55 and survive seven years to die at age 62. Early detection is only useful if the age of death goes up, and since the 1930s, despite the billions poured into a public campaign for early detection, yearly mammograms for breast cancer and PSA tests for prostate cancer have proven suspect in saving lives. On the other hand, recent studies show that colonoscopies, which are more invasive and expensive, do save lives.
Yet the overall decrease in cancers that could be prevented turns this picture around, since we are looking potentially at much bigger numbers. The good news is that each person can manage their own health holistically before and until medical education comes around. The core issue is compliance. Despite decades of public health advisories, Americans are growing more obese, stressed out, and sedentary than ever. The value of this new evidence about cancer is that science is backing up the program that holistic medicine has been promoting. There is no escaping what's good for you, and every year the reasons for practicing prevention grow more powerful. There is also the untold benefit of turning the public perception of cancer from one of deep dread to one of real hope -- that's a prospect that billions of dollars in research hasn't fulfilled.
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Flickr photo by danieljordahl