InteliHealth :

What's the latest news in the medical journals this month? Find out what your doctor is reading.

Benefit of Prostate Cancer Screening Still Uncertain
Heart Failure Occurs in 1 Out of 100 Blacks Before Age 50
Desensitizing Can Protect Kids With Peanut Allergy
More News in Brief: Dissolving Heart Stent Shows Good Two-Year Safety; Vertigo Linked to Higher Osteoporosis Risk

The March 18 online edition of the The New England Journal of Medicine published two studies that looked at whether screening tests could reduce the rate of death from prostate cancer. One out of every six men can expect to have prostate cancer in his lifetime, and about one out of every 32 men dies of prostate cancer. The studies came up with different answers, leaving doctors to debate whether PSA testing can save lives.

The first study, called the "Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial," randomly assigned 76,693 men at 10 U.S. study centers to a prostate-cancer screening group or a no-screening group. The men were 55 or older when they began the study.

Men in the screening group had a yearly prostate specific antigen (PSA) blood test and a rectal exam to check the prostate for lumps. After 7 to 10 years of follow-up, the death rate from prostate cancer was very low among all the men and did not differ significantly between the two groups.

The second study, based in Europe, also randomly divided 182,000 men between the ages of 50 and 74 into screening and no-screening groups. By the ninth year of the study, men in the screening group were 20% less likely to die of prostate cancer than men who didn't get screening. However, to prevent one death from prostate cancer 1,068 men had to be screened, and 48 men had to undergo cancer treatment.

Prostate cancer is the second leading cause of cancer death in men in the United States. As this study showed, a lot of men need to be treated to save one life.

Both surgery to remove the prostate (prostatectomy) and radiation therapy have serious drawbacks. For example, the chance of dying during surgery is about 1 in 200. Other complications and side effects include:

Recovery time – It can take about two months to recover from surgery, during which time you are out of work.

Incontinence – About 35% of men have some degree of long-term incontinence after surgery, at least when they sneeze, cough or lift heavy object.

Impotence – Most men are impotent after prostate cancer surgery, even with modern "nerve-sparing" techniques. Impotence also occurs in up to half of the men who have radiation treatment.

Rectal or bladder problems – Long-term rectal or bladder side effects, such as rectal bleeding, rectal spasms, an urgent feeling with bowel movements, diarrhea and urinary incontinence occur in less than 10% of men, but they can be unpleasant.

The good news is that prostate cancer isn't a lethal cancer in most men who have it. This could be why screening and early detection don't seem to result in fewer deaths. Given the complications and side effects of treatment, even the experts aren't sure if having the prostate specific antigen (PSA) blood test after age 50 is worth the trade-offs.

When a person has heart failure (also called "congestive heart failure" or CHF), the heart pumps blood less efficiently than normal. This can cause leg swelling, breathing discomfort and fatigue. It can also lead to premature death. Usually heart failure is a condition of older age. However, according to findings of a study published in the March 19 issue of the New England Journal of Medicine, heart failure affects approximately 1% of black people before age 50. This is an exceptionally high rate of "early-onset" heart failure in blacks compared to other racial groups.

The study observed 5,115 Americans from four cities over 15 years. Fifty-two percent of the participants were black; roughly half were women. All of the participants were adults under the age of 30 when the study began. They had physical exams every few years and telephone interviews every six months. The researchers wanted to trace the relationship between risk factors for heart disease and the start of symptoms from coronary artery disease.

From the beginning of the study, researchers noticed higher rates of risks factors for heart disease among blacks compared with other racial groups. These risks included high blood pressure, overweight build, low HDL cholesterol (the "good" cholesterol type), and kidney disease. At end of the study, the rate of heart failure among adults younger than age 50 was 20 times higher in blacks compared with whites. This was an unexpectedly large difference. The heart failure was clearly related to the high rates of risk factors for the black participants since they were in their 20's.

Doctors and public health experts are now struggling to understand why this disadvantage in heart health occurs. Genetics may explain part of it. But differences in access to care or in the amount of attention that blacks or their doctors give to preventive health care may also play a role. This study has shown doctors that it is crucial to manage heart-disease risk factors starting at a young age, and that blacks are at especially high risk.

We may soon be able to treat children with peanut allergy or other serious food allergies to prevent dangerous reactions, according to a report that was presented at the American Academy of Allergy, Asthma and Immunology meeting on March 15. It follows up on a previous study by researchers from Duke University who successfully desensitized a small number of children to peanut allergy over a 2½-year treatment process.

The researchers used a new approach called oral immunotherapy. It is modeled after allergy shots. Allergy shots work well to prevent some allergic reactions, but they are too risky to use for food allergies. The allergic children were exposed to peanut proteins when they swallowed very diluted amounts of peanut powder on a regular basis. The researchers wanted to see whether this method could have the same benefit as allergy shots.

The children had minute quantities of peanut protein mixed with their food every day. The dose was so small that they didn't have a noticeable reaction to the exposure. At the beginning of the study, this dose was 1/3,000 of a peanut. After gradual dose increases, the standard daily dose was a 1/10 of a peanut. Scientists caution families of children with a peanut allergy not to try this at home. This process requires great care in measuring the appropriate dose of peanut.

Oral immunotherapy probably works for the same reason that allergy shots do. After months or years of having a small but consistent exposure to your allergen, your body shifts to a different way of reacting to your trigger. You produce IgG antibodies. You also activate cells called "suppressor T cells." Your immune system is so busy making these harmless antibodies and cells that it makes very little IgE and histamine in reaction to your allergy trigger.

For the March 15 follow-up study, the researchers stopped the daily small doses of peanuts for a month or more before re-exposing nine children in their study to peanuts. The children had no allergic reaction when they ate 15 whole peanuts. This suggests that the process of oral desensitization may have fairly long-lasting results.

Thirty-three children have participated in the oral immunotherapy studies so far. The Duke researchers plan to expand their study to include another 80 children soon. Doctors are hopeful that if the results of the expanded study are successful, the treatment could be offered to all children with peanut allergy within the next several years.

Dissolving Heart Stent Shows Good Two-Year Safety. On March 12, The Lancet published a 2-year report card for a new kind of heart artery stent — the bioabsorbable stent. Unlike other stents, this one was designed to gradually disappear after initially reshaping and stabilizing a tight coronary artery. It was hoped that using a "vanishing" stent would reduce complications associated with other coronary artery stents. The first stents used were known as "bare-metal stents." They can cause a complication called "restenosis." As the lining of the artery heals, scar tissue can build up and narrow the artery again. To eliminate this proboem, "drug-coated stents" or "drug eluting stents" were developed. These stents did not cause restenosis, but they did raise the risk for heart attack due to blood clots forming on the stent. This study followed 30 patients who received the experimental stents. During the first two years after receiving the stents, no patients died and only one person had a heart attack. The newest "bioabsorbable" drug-eluting stents are not approved for wide use yet. But given these promising results, they may gain approval fairly soon for broader use.

Vertigo Linked to Higher Osteoporosis Risk. Vertigo is the sensation that either your body or surroundings are spinning or falling, even when you are not truly moving. The most common cause of vertigo is benign paroxysmal positional vertigo (BPPV). It occurs when mineral deposits break free from the bony structures within each inner ear. These bony structures are known as the "labyrinth," or "semi-circular canals." Symptoms occur when you turn your head. A study published March 24 in Neurology suggests that mineral changes in the inner ear are linked to mineral changes in other bones in the body. In this study, people who had BPPV were more likely to have osteoporosis, a significant loss of bone density that increases the risk of fracture. The reverse was also true: People with osteoporosis were more likely to have BPPV. Researchers looked at the bone mineral density of 209 people with BPPV symptoms. They compared their measurements to the bone density of 202 people with no vertigo. Among women in the study, 25% of those with vertigo showed signs of osteoporosis; only 9% of women without vertigo had this result. Forty-seven percent of women with vertigo had osteopenia — (bones that are thinner than normal, but not thin enough to be called osteoporosis), compared with 33% of women without vertigo. For men, 12% of those with vertigo had osteoporosis, and 40% of those with vertigo had osteopenia. Signs of osteoporosis were found in only 6% of men without vertigo; 27% had osteopenia. This link seems convincing, so doctors might consider screening people who have vertigo symptoms for osteoporosis. If you have osteoporosis, treatment to increase your bone density can lower your risk for fractures.

Mary Pickett, M.D. is an Associate professor at Oregon Health & Science University where she is a primary care doctor for adults. She supervises and educates residents in the field of Internal Medicine, for outpatient and hospital care. She is a Lecturer for Harvard Medical School and a Senior Medical Editor for Harvard Health Publications.

Update From the Medical Journals: March 2009