Friday, August 28, 2015

Coffee and Health: Consider the Evidence

Coffee and Health: Consider the Evidence
Mayo Clinic
Robert Sheeler, M.D.From the desk of:
Robert Sheeler, M.D. 
Medical Editor — Mayo Clinic Health Letter
Hello David!
News of coffee’s potential impact on health has for years gone back and forth. Initially, concerns centered on caffeine. In reality, coffee is the sum of many substances — some are known and many others aren’t. The most commonly recognized is caffeine, a naturally occurring stimulant. Some lesser known are compounds that have antioxidant properties. Antioxidants are generally associated with potential health benefits. As more becomes known, it appears as if the drink may be just fine for most, and possibly even of some benefit.
Interest in coffee’s pros and cons related to health has generated considerable research. Among the findings so far, coffee may protect against:
  • Type 2 diabetes — Researchers found that compounds in coffee — chlorogenic acid and caffeine — may thwart protein formation that contributes to the death of pancreas cells. Normally, pancreas cells produce insulin. An earlier study of younger and middle-aged women found that drinking two or more cups of coffee a day was associated with a substantially lower risk of type 2 diabetes.
  • Parkinson's disease — Numerous studies indicate regular coffee consumption may reduce the risk of Parkinson’s disease.
  • Various cancers — A recent study found that women who drank coffee reduced their risk of endometrial cancer by 20 percent. A recent analysis of multiple studies suggests there may be a correlation between drinking coffee and a reduced risk of pancreatic cancer. One study found that drinking an additional two cups of coffee a day was associated with a 43 percent reduced risk of liver cancer.
  • Alzheimer's disease — A recent review of multiple studies reported there’s a trend toward a protective effect from coffee, but more study is needed to determine if the trend is significant.
Areas where coffee may not be of help and may possibly be harmful are:
  • Bone health — Caffeine is known to increase the amount of calcium that’s passed in urine. It may also interfere with how well calcium is absorbed in the digestive tract. One study found that women who drank 20 ounces of coffee — about 2 1/2 cups — or more on a daily basis had a modest increase in fractures related to osteoporosis. However, other studies have found that if coffee drinkers get adequate calcium, the effect is minimized.
  • Blood pressure — For people who consume coffee only occasionally,
    there may be a temporary rise in blood pressure. However, regular coffee drinkers appear to develop a tolerance so that there isn’t much effect on blood pressure.
  • Lung health — A recent overview of 13 different studies concluded that high or increased coffee consumption might increase the risk of lung cancer. However, the authors of the overview also cautioned that other factors — specifically the effects of smoking — might have affected their findings. More study is needed to determine a connection — if indeed there is a connection.
Years of study have turned up little support for concerns about caffeine’s effect on cancer risk and heart health. For most healthy adults, moderate doses of caffeine — 200 to 300 mg a day, which is two or three cups of regular brewed coffee — are fine. Coffee is among the top 10 food sources of antioxidants. It’s also a major source of chlorogenic acid, which is one of its star players for antioxidant activity. Antioxidant activity associated with coffee has been linked to protective effects on multiple diseases, including cancer and cardiovascular diseases.
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Yours in good health,
Robert Sheeler, M.D.
Medical Editor — Mayo Clinic Health Letter

Thursday, August 27, 2015

TWO patients, I’ll call them Sara and Janine, both learned that they had ductal carcinoma in situ (D.C.I.S.), often referred to as Stage 0 breast cancer. Both underwent lumpectomies in their early 50s. Told that worrisome cells were found, both had another surgery. Then a third surgery was recommended.
Sara decided she would rather live with the risk. Janine had the opposite response. “Let’s get this all out,” she said.
Each is certain she made the best decision, but can both of them be right?
Each year about 60,000 American women are told that they have D.C.I.S., a cluster of cancer cells currently limited to the milk duct, but which may eventually spread. It used to be rare, but widespreadmammography has led to the discovery of more of these cancers. The logic of “catching it early” now has a twist: Despite the removal of thousands of D.C.I.S. lesions each year, there hasn’t been a drop in the incidence of invasive breast cancers. Some argue D.C.I.S. should not even be called cancer.
Now there’s a sense that some women with D.C.I.S. probably derive little benefit from treatment. But while treatment may not be helpful for some, we still don’t know enough to confidently say to any individual woman, “Your D.C.I.S. will never progress.” We are thus left treating virtually everyone.
Last week a study added to the confusion. The authors used a cancer incidence database to look at the chances of dying or having a recurrence among more than 100,000 women given a diagnosis of and treated for D.C.I.S. The primary finding, and one that can’t be overemphasized, is that the chances of dying from D.C.I.S. are quite low, about 3.3 percent at 20 years. Nevertheless, for some groups the risk was more than twice as high.
The most misleading suggestion from the media coverage would be that the study establishes the safety of not getting treatment. It does not.
The study does not compare treatment to no treatment because everyone was treated, as surgery is part of the standard of care. The opposite interpretation would be equally valid: Low mortality rates might instead show that treatment has been working.
Likewise, women who underwent a mastectomy had similar mortality rates to those who had a lumpectomy. Does this mean that a mastectomy is unnecessary? Perhaps. But maybe those who underwent a mastectomy had more troubling findings, prompting their doctors to recommend more extensive surgery, and so because they underwent a mastectomy, fared just as well. These data can’t distinguish between these two opposing conclusions.
The most pressing question then is whether a nonsurgical “watchful waiting” approach to D.C.I.S. would be safe and effective. The only way to answer this question is with randomized clinical trials, and some are underway. But a related question is whether a less-invasive approach is a tolerable choice for women with D.C.I.S.
Part of the challenge is that women with D.C.I.S. often overestimate their risk of disease recurrence and metastatic spread. Such heightened fears most likely contribute to the precipitous rise in preventive mastectomies of healthy breasts over the last decade among women with D.C.I.S. or other low-risk cancers who pursue surgery for peace of mind but are unlikely to derive survival benefit.
While communicating accurate risk information seems the obvious solution, the problem is that we don’t so much think risk, as we feel it. Fear can make unlikely risks feel highly probable. The concepts of overdiagnosis and overtreatment are more abstract. Few receive a diagnosis of D.C.I.S. and think “I’ve been overdiagnosed.” We think, instead, “I’m so relieved to have caught it early.” Overdiagnosis is a risk without feeling.
But among a different subset of women, emotions can cloud the perceived benefit of treatment. Perhaps the rush to conclude that D.C.I.S. therapy is unnecessary, in the absence of conclusive data, relates in part to broader impressions about the needless excesses and exorbitant costs of health care.
“Overtreatment” is easily conflated with “unnecessary” care. But they are quite different. Unnecessary care is getting antibiotics for a cold. It’s not only care that won’t help you, but care we know in advance won’t help you. But overtreatment is the Monday morning quarterbacking of cancer care: You can know it only retrospectively.
With breast cancer we know that some will endure the unnecessary risks of surgery, chemotherapy and radiation. That might mean more women should opt against treatment. But given that we don’t know who, or even how many, words like “brutal,” “aggressive” and “unnecessary” to describe surgery are value judgments themselves, suggesting a certainty far beyond what we actually know.
The key is to separate those emotions that may cloud judgment from those that clarify. Believing your risk of recurrence is high is quite different from understanding that it’s low, and nonetheless seeking treatment.
For Sara, who refused the third surgery, the recent coverage of the D.C.I.S. results resonated. “I think it was pretty unnecessary,” she said. She would have chosen active surveillance at the outset.
For Janine a nonsurgical approach seemed unbearable. “I’m not a watch and wait kind of person,” she explained.
Both of their decisions are right for them.
The medical community has a role not only in alleviating unwarranted fears, but also in identifying rational ones. Both are essential to making good decisions in the face of uncertain trade-offs.