Monthly Archives: February 2014
Twenty five year follow-up for breast cancer incidence
and mortality of the Canadian National Breast
Screening Study: randomised screening trial
Anthony B Miller professor emeritus1, Claus Wall data manager1, Cornelia J Baines professor emerita1, Ping Sun statistician2, Teresa To senior scientist3, Steven A Narod professor1 2
1Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario M5T 3M7, Canada; 2Women’s College Research Institute, Women’s College Hospital, Toronto, Ontario M5G 1N8, Canada; 3Child Health Evaluative Services, The Hospital for Sick Children, Toronto, Ontario, Canada
Objective To compare breast cancer incidence and mortality up to 25 years in women aged 40-59 who did or did not undergo mammography screening.
Design Follow-up of randomised screening trial by centre coordinators, the study’s central office, and linkage to cancer registries and vital statistics databases.
Setting 15 screening centres in six Canadian provinces,1980-85 (Nova Scotia, Quebec, Ontario, Manitoba, Alberta, and British Columbia).
Participants 89 835 women, aged 40-59, randomly assigned to mammography (five annual mammography screens) or control (no mammography).
Interventions Women aged 40-49 in the mammography arm and all women aged 50-59 in both arms received annual physical breast examinations. Women aged 40-49 in the control arm received a single examination followed by usual care in the community.
Main outcome measure Deaths from breast cancer.
Results During the five year screening period, 666 invasive breast cancers were diagnosed in the mammography arm (n=44 925 participants) and 524 in the controls (n=44 910), and of these, 180 women in the mammography arm and 171 women in the control arm died of breast cancer during the 25 year follow-up period. The overall hazard ratio for death from breast cancer diagnosed during the screening period associated with mammography was 1.05 (95% confidence interval 0.85 to 1.30). The findings for women aged 40-49 and 50-59 were almost identical. During the entire study period, 3250 women in the mammography arm and 3133 in the control arm had a diagnosis of breast cancer, and 500 and 505, respectively, died of breast cancer. Thus the cumulative mortality from breast cancer was similar between women in the mammography arm and in the control arm (hazard ratio 0.99, 95% confidence interval 0.88 to 1.12). After 15 years of follow-up a residual excess of 106 cancers was observed in the mammography arm, attributable to over-diagnosis.
For women who dutifully keep their mammogram appointments year after year, the latest results from a long-term trial in Canada, which found no difference in death rates from breast cancer among women who had regular mammograms and those who did not, are bound to sow confusion, perhaps even anger.
For decades now, the annual mammogram has been promoted vociferously and continuously as an essential way to protect oneself from breast cancer. Many women feel they are being irresponsible if they do not get a regular scan, said Dr. Lisa Schwartz, a professor at the Dartmouth Institute for Health Policy and Clinical Practice.
“For so long, we have been trying to convince people that you’re irresponsible or not taking care of yourself if you don’t do this,” Dr. Schwartz said. “People were hit over the head with that message.”
But attitudes have been changing as evidence accumulates of the hazards of intensive cancer screening. The American Urological Association has loosened its prostate cancer screening guidelines for men, for instance, because of the potential for unnecessary, invasive treatment that often leads to incontinence and impotence.
In light of the accumulating data that the benefits of regular mammography may be negligible for women, and that the practice has led to false positives and overtreatment, “it’s important for women to realize there is a genuine decision to be made here,” Dr. Schwartz said.
It is not a decision that medical groups are making any easier. In 2009, the United States Preventive Services Task Force, an influential group that makes recommendations to the federal government, concluded that women over age 50 should have mammograms every two years instead of annually and that the evidence of benefit was only moderate. The group did not recommend the screening test for younger women.
The American Cancer Society refrained from following the task force’s lead and continues to recommend annual mammograms beginning at age 40, as do the National Cancer Institute and the American College of Radiology.
In 2011, the American Congress of Obstetricians and Gynecologists urged more screening, recommending that women 40 and over receive a mammogram annually; previously, the group had recommended that women start yearly mammograms at age 50.
But the days of one-size-fits-all screening may be ending. Now patients and their doctors will face much more nuanced choices, based on each woman’s risk for breast cancer and her feelings about the prospect of unnecessary treatment.
“The balance between benefits and harms is more and more up in the air,” said Dr. Russell P. Harris, a professor of medicine at the University of North Carolina, Chapel Hill. “Reasonable people will disagree.”
One of the largest and most meticulous studies of mammography ever done, involving 90,000 women and lasting a quarter-century, has added powerful new doubts about the value of the screening test for women of any age.
It found that the death rates from breast cancer and from all causes were the same in women who got mammograms and those who did not. And the screening had harms: One in five cancers found with mammography and treated was not a threat to the woman’s health and did not need treatment such as chemotherapy, surgery or radiation.
The study, published Tuesday in The British Medical Journal, is one of the few rigorous evaluations of mammograms conducted in the modern era of more effective breast cancer treatments. It randomly assigned Canadian women to have regular mammograms and breast exams by trained nurses or to have breast exams alone. Researchers sought to determine whether there was any advantage to finding breast cancers when they were too small to feel. The answer is no, the researchers report. The study seems likely to lead to an even deeper polarization between those who believe that regular mammography saves lives, including many breast cancer patients and advocates for them, and a growing number of researchers who say the evidence is lacking or, at the very least, murky.
“It will make women uncomfortable, and they should be uncomfortable,” said Dr. Russell P. Harris, a screening expert and professor of medicine at the University of North Carolina, Chapel Hill, who was not involved in the study. “The decision to have a mammogram should not be a slam dunk.”
The findings will not lead to any immediate change in guidelines for mammography, and many advocates and experts will almost certainly dispute the idea that mammograms are on balance useless, or even harmful.
Dr. Richard C. Wender, chief of cancer control for the American Cancer Society, said the society had convened an expert panel that was reviewing all studies on mammography, including the Canadian one, and would issue revised guidelines later this year. He added that combined data from clinical trials of mammography showed it reduces the death rate from breast cancer by at least 15 percent for women in their 40s and by at least 20 percent for older women.
That means that one woman in 1,000 who starts screening in her 40s, two who start in their 50s and three who start in their 60s will avoid a breast cancer death, Dr. Harris said.
Dr. Wender added that while improved treatments clearly helped lower the breast cancer death rate, so did mammography, by catching cancers early.
But an editorial accompanying the new study said that earlier studies that found mammograms helped women were done before the routine use of drugs like tamoxifen that sharply reduced the breast cancer death rate. In addition, many studies did not use the gold-standard methods of the clinical trial, randomly assigning women to be screened or not, noted the editorial’s author, Dr. Mette Kalager, and other experts.
Dr. Kalager, an epidemiologist and screening researcher at the University of Oslo and the Harvard School of Public Health, said there was a reason the results were unlike those of earlier studies. With better treatments, like tamoxifen, it was less important to find cancers early. Also, she said, women in the Canadian study were aware of breast cancer and its dangers, unlike women in earlier studies who were more likely to ignore lumps.
“It might be possible that mammography screening would work if you don’t have any awareness of the disease,” she said.
The Canadian study reached the same conclusion about the lack of a benefit from mammograms after 11 to 16 years of follow-up, but some experts predicted that as time went on the advantages would emerge.
Many cancers, researchers now recognize, grow slowly, or not at all, and do not require treatment. Some cancers even shrink or disappear on their own. But once cancer is detected, it is impossible to know if it is dangerous, so doctors treat them all.
If the researchers also included a precancerous condition called ductal carcinoma in situ, the overdiagnosis rate would be closer to one in three cancers, said Dr. Anthony B. Miller of the University of Toronto, the lead author of the paper. Ductal carcinoma in situ, or D.C.I.S., is found only with mammography, is confined to the milk duct and may or may not break out into the breast. But it is usually treated with surgery, including mastectomy, or removal of the breast.
Mammography’s benefits have long been debated, but no nations except Switzerland have suggested the screening be halted. In a recent report, the Swiss Medical Board, an expert panel established by regional ministers of public health, advised that no new mammography programs be started in that country and that those in existence have a limited, though unspecified, duration. Ten of 26 Swiss cantons, or districts, have regular mammography screening programs.
Dr. Peter Juni, a member of the Swiss Medical Board until recently, said one concern was that mammography was not reducing the overall death rate from the disease, but increasing overdiagnosis and leading to false positives and needless biopsies.
“The mammography story is just not such an easy story,” said Dr. Juni, a clinical epidemiologist at the University of Bern.
Even experts like Dr. H. Gilbert Welch, a professor of medicine at Dartmouth, who have questioned mammography’s benefits were surprised by Switzerland’s steps to reconsider its widespread use.
“Wow, times they are a-changin’,” Dr. Welch said.
In the United States, about 37 million mammograms are performed annually at a cost of about $100 per mammogram. Nearly three-quarters of women age 40 and over say they had a mammogram in the past year. More than 90 percent of women ages 50 to 69 in several European countries have had at least one mammogram.
Dr. Kalager, whose editorial accompanying the study was titled “Too Much Mammography,” compared mammography to prostate-specific antigen screening for prostate cancer, using data from pooled analyses of clinical trials. It turned out that the two screening tests were almost identical in their overdiagnosis rate and had almost the same slight reduction in breast or prostate deaths.
“I was very surprised,” Dr. Kalager said. She had assumed that the evidence for mammography must be stronger since most countries support mammography screening and most discourage PSA screening.
DNA Studies Lend Weight to New Way of Looking at Cancer
Dr. Douglas Levine of Memorial Sloan Kettering Cancer Center is the principal investigator on the endometrial cancer study.
By GINA KOLATA
Published: May 1, 2013 81 Comments
To the surprise of scientists, the most dangerous cancers of the uterine lining closely resemble the worst ovarian and breast cancers, raising the tantalizing possibility that the three deadly cancers might respond to the same drugs.
Peter Newcomb for The New York Times
According to Dr. Timothy Ley, traditional methods for categorizing acute myeloid leukemia were imprecise.
This finding, part of a major new study, is the best evidence yet that cancer will increasingly be seen as a disease defined by its genetic fingerprint rather than by the organ where it originated, researchers say.
The study of endometrial cancer — a cancer of the uterine lining — and another of acute myeloid leukemia, published simultaneously on Wednesday by Nature and the New England Journal of Medicine, are part of a sprawling, ambitious project by the National Institutes of Health to scrutinize DNA aberrations in common cancers. The endometrial cancer and leukemia efforts alone involved more than 100 researchers who studied close to 400 endometrial tumors and 200 leukemias.
“This is exploring the landscape of cancer genomics,” said Dr. David P. Steensma, a leukemia researcher at the Dana-Farber Cancer Institute who was not involved with the studies. “Many developments in medicine are about treatments or tests that are only useful for a certain period of time until something better comes by. But this is something that will be useful 200 years from now. This is a landmark that will stand the test of time.”
Endometrial cancer is the most common gynecological cancer in American women and strikes nearly 50,000 of them a year, killing about 8,000. Acute myeloid leukemia, the most prevalent acute adult leukemia, is diagnosed in about 14,000 Americans a year and kills about 10,000.
The acute myeloid leukemia study identified virtually all of the common genetic malfunctions that occur in it, providing a new foundation for assessing which cancers will be lethal unless the patient gets a risky bone marrow transplant and which can be treated with chemotherapy alone.
Dr. Douglas Levine of Memorial Sloan Kettering Cancer Center, the principal investigator on the endometrial cancer study, said the group scoured the country for samples of this cancer.
The cancer has long been evaluated by pathologists who examine thin slices of endometrial tumors under a microscope and put them in one of two broad categories. But the method is not ideal. In general, one category predicts a good prognosis and tumors that could be treated with surgery and radiation, while the other holds a poorer prognosis and required chemotherapy after surgery. But pathologists often disagree about how to classify the tumors and can find it difficult to distinguish between the two types, Dr. Levine said.
The new genetic analysis of hundreds of tumors found patterns of genetic aberrations that more precisely classify the tumors, dividing them into four distinct groups. About 10 percent of tumors that had seemed easily treated with the old type of exam now appear to be more deadly according to the genetic analysis and would require chemotherapy.
Another finding was that many endometrial cancers had a mutation in a gene that had been seen before only in colon cancers. The mutation disables a system for repairing DNA damage, resulting in 100 times more mutations than typically occur in cancer cells.
“That was a complete surprise,” Dr. Levine said.
It turned out to be good news. Endometrial cancers with the mutation had better outcomes, perhaps because the accumulating DNA damage is devastating to cancer cells.
Another surprise was that the worst endometrial tumors were so similar to the most lethal ovarian and breast cancers.
Jeff Boyd, executive director of the cancer genome institute at Fox Chase Cancer Center, who was not involved with the new research, said the similarity between breast, ovarian and endometrial tumors was the best example yet of the idea that cancers are more usefully classified by their gene mutations than by where they originate. Though many scientists believe this view is correct, Dr. Boyd said, “It is very rewarding — I can’t overstate it” to see it validated with real data.
While the genetics of endometrial cancer had gone largely unstudied until now, acute myeloid leukemia has been investigated for decades, in part because leukemia cells are so accessible. They are in the blood and bone marrow.
Using microscopes and special staining methods, researchers had already discovered, for example, that chromosomes in these leukemia cells are often broken or hooked together in strange ways. They also knew that some chromosomal alterations were associated with a good prognosis, and others with a bad one. Patients with a good prognosis can usually be treated with chemotherapy alone, while those with a worse prognosis needed the expensive, difficult and risky treatment of last resort: a bone marrow transplant. It comes with a 10 percent death rate.
The problem was that the traditional methods for categorizing the leukemia were imprecise, said Dr. Timothy Ley of Washington University in St. Louis, who led the study with Richard Wilson, also of Washington University. Nearly half the acute myeloid leukemias had normal chromosomes. There was no good way to decide which treatment these patients needed. Some did well with chemotherapy, some did poorly.
“It was a huge conundrum,” Dr. Ley said. “For patients who cannot be cured with chemotherapy, we have a potentially curative therapy. But picking the right patients for a transplant was very difficult.”
The new study of 200 acute myeloid leukemias identified at least 260 genes that were mutated in at least two of the 200 leukemia samples.
“We have the basic playbook,” Dr. Ley said. “We finally know what the major pathways are and what all the major mutations look like.”
The next step will be for investigators to determine which mutations lead to good or bad outcomes. And knowing which genes are mutated also allows researchers to investigate drugs that target those genes.
“Within two or three years, risk assessment may be dramatically better,” Dr. Ley said. “It certainly sets the stage for the next era of therapy.”
Mining for hidden salt
You can easily tick off a list of salty, sodium-rich foods: potato chips, popcorn, hot dogs, pizza, pickles, and more. But there are plenty of high-sodium foods you probably aren’t aware of. According to the Centers for Disease Control, Americans get almost one-third of their sodium from breads and rolls, chicken and chicken dishes, pizza, egg dishes, and pasta dishes. That’s partly because these foods contain added salt and partly because we eat them so often. Here’s another staggering number: up to 80% of the salt in your food was put there by someone other than you.
Why does salt matter? Your body needs a little bit of the sodium in salt to contract muscles, send nerve impulses, and maintain a healthy balance of fluids. But too much sodium can increase blood pressure, make the heart work harder, thicken and stiffen blood vessels, and more. Higher salt and sodium consumption have been linked to increased risk of heart disease and stroke.
How can you avoid these hidden salt mines? Read food labels carefully. Look at both the amount of sodium per serving and the recommended daily sodium allowance percentage. Shop for products labeled “salt free,” or “no salt added,” or “low-sodium.” Avoid condiments such as soy sauce, ketchup, teriyaki sauce, and salad dressings, which tend to be loaded with salt.
Another good strategy is to limit your use of prepared and processed foods, which tend to be made with a lot of salt. Adding more fresh or frozen fruits and vegetables to your diet can also lower sodium and increase potassium.
Restaurant foods are often loaded with salt. Many restaurants now offer low-sodium choices. If your food is being made to order, don’t hesitate to ask that it be made without salt.
Study advances LSUHSC research, shows fish oil component reduces brain damage in newborns
New Orleans, LA – Research conducted by a team of scientists from Columbia University College of Physicians and Surgeons and Dr. Nicolas Bazan, Boyd Professor and Director of the Neuroscience Center of Excellence at LSU Health Sciences Center New Orleans, found the novel use of a component of fish oil reduced brain trauma in newborn mice. The study reports that neonatal brain damage decreased by about 50% when a triglyceride lipid emulsion containing docosahexaenoic acid (DHA) was injected within two hours of the onset of ischemic stroke. The paper, n-3 Fatty Acid Rich Triglyceride Emulsions are Neuroprotective after Cerebral Hypoxic-Ischemic Injury in Neonatal Mice, is published in the journal, PLOS ONE, available online at http://dx.plos.org/10.1371/journal.pone.0056233.
The study compared the effectiveness of emulsions with two omega-3 fatty acids – DHA and eicosapentaenoic acid (EPA) – as well as optimal doses and therapeutic window. The researchers found that DHA provided protection while EPA did not. The therapeutic window ranged from 90 minutes prior to several hours after with the optimal window for treatment 0 – 2 hours. There was no protective effect at hour 4.
DHA is an essential omega-3-fatty acid and is vital for proper brain function. It is also necessary for the development of the nervous system, including vision. Moreover, omega-3 fatty acids, found in cold water fatty fish, including salmon, tuna, mackerel, sardines, shellfish, and herring, are part of a healthy diet that helps lower the risk of heart disease. DHA has potent anti-inflammatory effects. Since inflammation is at the root of many chronic diseases, DHA treatment has been widely demonstrated to have beneficial effects in patients with coronary heart disease, asthma, rheumatoid arthritis, osteoporosis, sepsis, cancer, dry eye disease, and age-related macular degeneration. Its potential benefit in stroke is now being documented.
EPA is also an omega-3 fatty acid found in coldwater fish. EPA can prevent the blood from clotting easily. Often paired with DHA in fish oil supplements, these fatty acids are known to reduce pain and swelling.
Ischemic strokes, representing about 87% of strokes, result from loss of blood flow to an area of the brain due to a blockage such as a clot or atherosclerosis. The damage includes an irreversibly injured core of tissue at the site of the blockage. The area of tissue surrounding the core, called the penumbra, is also damaged but potentially salvageable. The penumbra has a limited life span and appears to undergo irreversible damage within a few hours unless blood flow is reestablished and neuroprotective therapy is administered. A cascade of chemicals floods the tissue along with restored blood flow, including damaging free radicals and pro-inflammatory enzymes which can cause further damage and cell death.
Administering clot-busting drugs (thrombolysis) is currently the only treatment for ischemic stroke. But due to a narrow therapeutic window and complexity of administration, only 3–5% of patients typically benefit from thrombolysis.
Dr. Bazan’s group at the LSU Health Sciences Center New Orleans Neuroscience Center of Excellence has increasingly shown that DHA is a potentially powerful treatment for stroke for nearly ten years. His study published in 2011 found DHA triggered production of Neuroprotectin D1 (NPD1), a naturally occurring neuroprotective molecule in the brain derived from DHA and discovered by Dr. Bazan. Not only did DHA treatment salvage stroke-damaged brain tissue that would have died, its repair mechanisms rendered some areas indistinguishable from normal tissue by 7 days.
“Stroke is a brain attack that each year kills 130,000 Americans,” notes Dr. Bazan. “Strokes can occur at any age, including in newborns, with long-term and devastating consequences. DHA is already widely consumed as a dietary supplement in the US, and from a therapeutic point of view, we can now see a light at the end of the tunnel.”
The researchers conclude that the findings suggest a need for further studies to determine if acute injection of these emulsions could be neuroprotective after stroke injury in humans. They also suggest that the emulsion rich in DHA will prove to be a novel and important therapy to treat stroke and could decrease mortality and increase long-term functional recovery after stroke in humans of different ages. The paper’s senior author is Richard Deckelbaum, MD, director of the Institute of Human Nutrition at Columbia’s College of Physicians & Surgeons.
According to the Centers for Disease Control and Prevention, 795,000 Americans have a stroke each year, and stroke causes 1 in every 18 deaths. Stroke is also a leading cause of long-term disability. Louisiana is among the states with the highest prevalence of stroke. It has been estimated that the direct and indirect costs of stroke in the United States totaled nearly $74 billion in 2010. In addition, with an estimated incidence of 1 in 2300 to 5000 births, stroke is more likely to occur in the perinatal period than at other times in childhood. Ischemic stroke in newborns is a disorder associated with significant long-term neurologic impairment. Twenty to 60% of survivors exhibit long-term detrimental neuropsychological consequences which include mental retardation, cerebral palsy, and behavioral disorders.
The research team also included Jill J. Williams, Korapat Mayurasakorn, and Vadim S. Ten at Columbia University; Susan J. Vannucci at Weill Cornell Medical College; and Christopher Mastropietro at Wayne State University.
The research was supported by grants from the National Institutes of Health.
LSU Health Sciences Center New Orleans educates Louisiana’s health care professionals. The state’s academic health leader, LSUHSC comprises a School of Medicine, the state’s only School of Dentistry, Louisiana’s only public School of Public Health, and Schools of Allied Health Professions, Nursing, and Graduate Studies. LSUHSC faculty take care of patients in public and private hospitals and clinics throughout the region. In the vanguard of biosciences research in a number of areas in a worldwide arena, the LSUHSC research enterprise generates jobs and enormous economic impact. LSUHSC faculty have made lifesaving discoveries and continue to work to prevent, advance treatment, or cure disease. To learn more, visit http://www.lsuhsc.edu and http://www.twitter.com/LSUHSCHealth.
A report published in the Journal of the National Cancer Institute late last week shows a potential link between omega-3 fatty acids and the risk of developing prostate cancer. But it may be premature for people to reduce their omega-3 intake until we have a better understanding of what lies behind…
A report published in the Journal of the National Cancer Institute late last week shows a potential link between omega-3 fatty acids and the risk of developing prostate cancer.
But it may be premature for people to reduce their omega-3 intake until we have a better understanding of what lies behind this apparent association.
Omega-3 fatty acids are a class of polyunsaturated fats found in marine and plant oils that are considered essential for health. Plants contain alpha-linolenic acid (ALA), the short-chain omega-3 precursor that is elongated to form the more beneficial long-chain acids (EPA, DPA and DHA) found in marine sources.
This conversion is limited in humans; less than 1% of ALA is converted through to DHA. Hence the Nutrient Reference Values for Australia and New Zealand and the National Heart Foundation recommend consumption of pre-formed long chain omega-3 obtainable from fish, fish oil and krill oil, in addition to consumption of ALA from plant sources such as canola, chia, flaxseed, soy and various nuts.
News of potential adverse association with prostate cancer comes at a time when the public have been heeding the message that the omega-3s derived from marine sources are beneficial for cardiovascular health, counteracting inflammatory conditions, such as rheumatoid arthritis, and possibly improving mood and cognitive performance.
A potential link between prostate cancer and consumption of ALA was reported more than a decade ago but was subsequently dismissed due to lack of supportive evidence. And with the realisation that ALA contributes little to the health benefits ascribed to omega-3, attention has focused more recently on the effects of the long-chain omega-3s.
We can now assess the “omega-3 status” of an individual from the levels of these fatty acids accumulating in certain fractions of the blood. And a strength of the current report is that it examined associations between blood levels of long-chain omega-3 rather than estimating intakes from dietary records, which is notoriously imprecise.
The report indicated that DHA, the omega-3 considered most important for conferring cardiovascular benefits, has the strongest association with high-grade prostate cancer – the authors included their latest findings in a meta-analysis in the same report, which indicates a 48% increase in relative risk of high-grade prostate cancer.
Most cancer risk factors are associated with unhealthy diets and lifestyles, so, on one level, this conflicts with current nutrition advice promoting increased omega-3 consumption to reduce the risk of chronic disease. It also challenges conventional thinking on the benefits versus risks of omega-3 supplementation.
The right dose
Up until now, long-chain omega-3s have been considered very safe. There was a minor concern that fish oil supplementation may prolong bleeding, although the risk is no greater than that posed by a low dose of aspirin. Both can help reduce the risk of potentially lethal blood clots.
Australia has adopted the generally-recognised-as-safe limit of three grams of omega-3 fatty acids per day (equivalent to around ten standard fish oil capsules) as recommended intake.
The level recommended for reducing the risk of chronic disease, particularly for maintaining heart health, is only 0.5 grams per day (one-sixth of the upper limit) but, on average, Australians consume only 0.2 grams of omega-3 per day.
That means, ideally, they should be consuming an extra 0.3 grams per day, equivalent to the omega-3 content of a typical fish oil capsule or a weekly serve of oily fish.
Too much of a good thing?
There are cases where, at excessive intakes, beneficial nutrient supplements, such as antioxidants, may have detrimental effects.
But that doesn’t explain the present finding. The levels of omega-3 that the prostate cancer study authors refer to are not extreme – they can be achieved through consumption of fish alone, without popping capsules.
The range of omega-3 levels from low risk to high risk as described in the study are within the range attainable by variations in the amount of omega-3 consumed in typical Australian diets.
While this observation raises concern, there’s a lot more we need to understand before we can properly balance the risk-versus-benefit equation for omega-3 consumption.
In the absence of trials that can demonstrate a causal relationship, we need to have a clearer understanding of possible underlying mechanisms. It’s known, for example, that omega-3 oils can influence certain male reproductive mechanisms, such as sperm production and motility, but there is currently no hypothesis to explain how they might influence prostate cancer risk.
At the same time, evidence is mounting for protective effects of omega-3 consumption in breast and other cancers
Until now, the risk factors for fish oil supplementation have been considered to be minimal. Even if a causative relationship between omega-3 consumption and prostate cancer is confirmed, consumers will need to weigh up their cancer risk against the known cardiovascular benefits before giving up on omega-3 fatty acids.
Regular exercise is the most significant lifestyle parameter associated with the severity of climacteric symptoms: a cross sectional study.
Department of Obstetrics and Gynecology, Hadassah Hebrew University Medical Center, Jerusalem, Israel. Electronic address: firstname.lastname@example.org.
To assess the association between demographic and lifestyle parameters and perceived severity of the climacteric syndrome in perimenopausal women.
A cross-sectional study of 151 healthy women aged 45-55 years who attended the University Medical Center affiliated menopause clinics. The analysis was based on self completion of the Greene climacteric score, consisting of psychological, somatic/physical, sexual and vasomotor subscores. The Greene total score and subscores were the main outcomes of the study.
Of all demographic, anthropometric and lifestyle parameters recorded, the correlates with reduced total Greene score were high-order maternity and regular physical exercise. Mothers of 3 or more children reported significantly lower total Greene score (18±12.8 vs. 22.1±8.1) (p=0.01) as well as lower psychological subscore (8.7±6.8 vs. 11.5±5.4) (p=0.01). Regular physical activity was also associated with significantly lower total Greene score (17.0±11.0 vs. 22.6±11.3) (p=0.01) and specifically lower psychological subscore (9.5±6.6 vs. 12.8±7.7) (p=0.03) and sexual subscore (1.1±0.99 vs. 1.61±1.05) (p=0.03). Linear regression models showed that regular exercise was the lifestyle parameter most significantly correlated with a lower total Greene score (p=0.006) independent of menopausal status. Of particular note, regular exercise was significantly correlated with lower psychological (p=0.006) and physical subscores (p=0.06). Moreover, the higher the frequency of exercise (both aerobic and non aerobic), the lower the severity of the climacteric symptoms reported, yet the vasomotor and sexual subscores remained unchanged.
Regular exercise of at least 3 times a week was the most significant lifestyle parameter to be associated with the severity of climacteric symptoms.
Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
Exercise, Greene scale, Lifestyle, Menopause, Physical activity
- [PubMed – in process
Oral contraceptives should be in vending machines and cigarettes on prescription
I am continuing my weekly blog built around the large undergraduate class I co-teach on Poverty and Population. The philosophy of the class has been well summarized by the economist Partha Dasgupta in a recent Science article. He pointed out that, “Family planning is not subject to the play of free markets; it is biased by restrictive laws, widespread misinformation, and rules not based on evidence.”
The history of oral contraceptive illustrates such biases in a compelling way. In the 1960s I had helped found a clinic for the unmarried in Cambridge, England when offering contraception to couples having premarital intercourse was still highly controversial.
Many women wanted the Pill but were afraid to use it. Early formulations of oral contraceptives had a much higher dose of hormones than today’s products and they did cause a slight, but still tragic increase in the risk of death from cardiovascular disease. The deaths that occurred hit the headlines. A US congressional committee wanted to take the Pill off the market.
Nearly all preventive measures have a downside and one of the conundrums of public health is how to express such risks in readily understood terms. I did a quick calculation and began telling women wanting oral contraceptives that the risk of death was approximately the same as that of smoking one third of a cigarette each day. The women would visibly relax. Today’s much lower-dose Pills have almost eliminated cardiovascular risks, but the aura of yesterday’s adverse publicity and misinformation persists.
In the 1960s the British Medical Research Council had the good sense to begin a trial of 27,000 women using the Pill and 27,000 matched controls. Thirty nine years later a follow-up, involving 1.2 million women years of observation, demonstrated that women who took the Pill (usually, of course, for only a few years) enjoyed life-long, non-contraceptive health benefits. Oral contraceptive use significantly reduces the risk of ovarian and uterine cancer, and also of bowel cancer and melanoma. There is no other drug that I can prescribe as a doctor which offers a significant and proven reduction in the risk of dying from certain cancers.
But why is such a safe drug on prescription in the first place?
A remark that I made on a television show in the 1960s – a sort of Jon Stewart show of the time – that Pills should be in vending machines and cigarettes on prescription went viral. Today the scientific evidence that oral contraceptive should be sold over-the-counter (o-t-c) is impeccable and it has been endorsed by the American College of Obstetricians and Gynecologists.
Big pharma makes more money from prescription drugs than o-t-c and refuses to make the switch. Anyone who has got to the end of this blog and knows an entrepreneur willing to challenge big pharma please contact me. The first in the o-t-c market for oral contraceptives could make a substantial profit.
Gretchen Reynolds on the science of fitness.
Physical activity, even including walking, can substantially reduce a woman’s risk of developing breast cancer, encouraging new science shows, in part, it seems, by changing how her body deals with estrogen.
Evidence has been accumulating for some time that exercise reduces the risk of many types of cancer, including breast malignancies. But the physiological mechanisms involved have not been well characterized, nor have scientists known what kinds and amounts of exercise provide the surest protection.
Which makes the results of two recently published studies of considerable interest to women and those of the remaining gender who love us.
In the newest and largest of these studies, published online last week in Cancer Epidemiology, Biomarkers & Prevention, researchers with the Epidemiology Research Program at the American Cancer Society began by turning to a huge trove of data maintained by the cancer society. The database includes detailed health and medical information from more than 73,600 postmenopausal women, age 50 to 73, who enrolled in the study in the early 1990s. For almost two decades, they completed follow-up questionnaires every two years.
The questionnaires asked, among other things, for detailed descriptions of how the women spent their leisure time and in particular whether and how they exercised. About 9 percent reported never exercising. A few said that they exercised vigorously and often, typically by running, swimming or playing singles tennis.
But most walked, usually at a pleasant pace of about 3 miles per hour. About half of the group reported that such strolling was their only form of exercise.
Over the course of the study, 4,760 of the women enrolled developed breast cancer.
When the researchers cross-tabulated exercise regimens and medical records, they found that those women who walked at least seven hours per week, usually distributed as an hour a day, had 14 percent less risk of developing breast cancer than those who walked for fewer than three hours per week, a significant reduction in risk.
Meanwhile, those few women who were the most active, sweating vigorously for up to 10 hours each week, realized an even greater benefit, with 25 percent less risk of developing breast cancer than those women who exercised the least.
These risk reductions held true, the researchers determined, whether or not the women were overweight and whether or not they were using hormone replacement therapy.
“We think these results are very encouraging,” said Alpa V. Patel, a senior epidemiologist with the American Cancer Society and senior author of the study. “Walking is an easy, inexpensive type of exercise. Almost everyone can do it. And for this population of postmenopausal women, it provided a very significant reduction in the risk of breast cancer.”
Another intriguing study that looked at younger women, published in May in Cancer Epidemiology, Biomarkers & Prevention, helps to elucidate how exercise may reduce breast cancer risk. For this experiment, scientists from the School of Public Health at the University of Minnesota divided several hundred sedentary, premenopausal women into two groups. One group remained sedentary, while the other began a moderate aerobic exercise program that continued five times a week for 16 weeks.
At the start and end of the four months, the researchers collected urine and tested it for levels of estrogen and various estrogen metabolites, the substances that are formed when estrogen is broken down by the body. Past studies have found that a particular ratio of these metabolites in a woman’s urine indicates a heightened risk of breast cancer during her lifetime.
In this study, those volunteers who remained sedentary showed no changes in the ratios of their estrogen metabolites after four months.
But among the group that began exercising, the levels of one of the metabolites fell and another rose, shifting the ratio in ways that are believed to indicate less chance of breast cancer. The women also lost body fat and gained muscle.
This finding, although derived from younger women, has implications for women of any age. As Dr. Patel pointed out, postmenopausal women produce estrogen, although in much smaller doses and primarily from fat cells and not the ovaries.
Exercise, by altering the ratio of estrogen metabolites and also reducing total body fat, may change the internal makeup of a woman’s body and make it harder for breast cancer to take hold.
But, of course, exercise, is not a panacea. Some of the women in Dr. Patel’s study who dutifully walked every day developed breast cancer. Many who rarely if ever exercised did not.
“There is still a very great deal that we don’t know” about how cancer of any kind starts or why it doesn’t, Dr. Patel said.
“But physical activity, and especially walking, are so simple and so accessible to most women,” she continued. “And statistically, they do seem to reduce breast cancer risk. So why not?”
- Elizabeth Renant
- New Mexico
I am getting really tired of these articles. “Substantially” reduce the risk of getting breast cancer??!!! Exactly what does “substantially” mean?
Peggy Fleming, a slim, incredibly active and fit Olympic athlete, got breast cancer 15 years ago, while still under 60.
This is the kind of junk that women exhausted from exhortations have coming at them from every side, filled with confusing information, that essentially has little effect except to shift more blame on women for getting breast cancer. We just didn’t try hard enough. We didn’t avoid the occasional glass of red wine, we occasionally treated ourselves to a burger and fries, we didn’t live on tofu and broccoli, and now, of course, we didn’t walk enough.
As I head for my 8-5 office job, gulping my lunch down at my desk and lucky if I don’t have six errands to do in that 60 minutes I get out of those 9 hours, stop for groceries on the way home, cook, clean, pick up dry cleaning,pay bills after supper, etc., I’ll make sure I fit in seven hours of walking per week.
You really think just “walking” is that accessible to most women??!! Get a grip and stop shoving this stuff at women – we are already terrified, anxious, and guilty enough for everything an unreasonable society expects of us that we can’t possibly do. Eventually, we’re all going to die of something. You can walk your butt off and still get breast cancer. These articles are dangerous to women’s peace of mind.