Hormone therapy begun at menopause may pose risk for breast cancer
2011-01-29
(Press-News.org) Starting hormone therapy at around the time of menopause is associated with a greater risk of breast cancer compared to starting after a longer gap, according to a study published online Jan. 28 in The Journal of the National Cancer Institute. In this large, prospectively followed cohort of women, those who started hormone therapy five years or more after menopause had little or no increased risk, regardless of the type of hormone therapy used, how long they used it, and whether they were overweight or obese.
Many studies have established that breast cancer incidence increases in users of hormonal therapy, in particular among women who use an estrogen-progestin combination as opposed to estrogen-alone. Few studies have looked at the timing of hormone therapy as a risk factor, although two previous studies suggested the interval between menopause and initiating hormone therapy may influence breast cancer risk.
To investigate this question, Valerie Beral, FRS, of Oxford University and colleagues, used data from the Million Women Study (MWS) in the UK. The researchers estimated the adjusted relative risks of breast cancer in hormone therapy users and past users compared to non-users in 1.13 million women in the study. They also compared women on different types of hormone therapy.
They found that women starting hormone therapy at the time of menopause were at greater risk of breast cancer than those starting it later. They write, "A new finding of this study, which has been little investigated previously, is that the interval between menopause and starting hormonal therapy has a substantial effect on breast cancer risk."
Two previous studies have suggested this association but only in certain subgroups. "In this large study, we found greater risks of breast cancer if hormonal therapy use began either before or soon after menopause than after a longer gap; and this pattern of risk was seen across different types of hormonal therapy, among women who used hormonal therapy for either short of long durations, and also in lean and in overweight and obese women."
In an accompanying editorial, Rowan T. Chlebowski, M.D., Ph.D., of Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center and Garnet Anderson from the Fred Hutchinson Cancer Research Center note the study provides substantial support for similar findings from the Women's Health Initiative (WHI) in the U.S. They add that the similarities between the patterns of breast cancer risk in these two large studies increase the likely validity of the results, especially since the methodologies of the two studies were quite different.
The editorialists also discuss discrepancies in the two studies' findings regarding the risk of estrogen-only hormone therapy; the WHI found little risk associated with estrogen alone while the MWS found a statistically significant increased risk, except in overweight and obese women. They conclude that "the question of the effect of estrogen-only formulation use on breast cancer risk in postmenopausal women, even with longer-term hormone use, still stands unanswered."
INFORMATION:
Contacts:
Article: Cancer Research UK press office, +440203469 8300, pa.valerie.beral@ceu.ox.ac.uk
Editorial: Laura Mecoy, communications consultant, Los Angeles Biomedical Research Institute, 310-546-5860, lmecoy@issuesmanagement.com
ELSE PRESS RELEASES FROM THIS DATE:
2011-01-29
Many different aspects are involved in predicting high water and floods, such as the type of precipitation, wind, buildings and vegetation. The greater the number of variables included in predictive models, the better the prediction will be. However, the models will inevitably become increasingly more complex. PhD student from Delft University of Technology (TU Delft, The Netherlands) Steven Weijs uses basic insight from the information theory (Shannon's Information Theory) to demonstrate the cohesion between this added complexity, the information from observational data ...
2011-01-29
Exposure to worm infections in the womb may protect a newborn infant from developing eczema, a study funded by the Wellcome Trust suggests. A large trial in Uganda showed that treating a pregnant woman for worm infections increased her child's chances of developing the allergic skin disease.
Published this week in the journal Pediatric Allergy and Immunology, the research supports the so-called 'hygiene hypothesis', which proposes that exposure to infections in early childhood can modify the immune system and protect the child from allergies later in life.
The World ...
2011-01-29
After a spinal cord injury a number of factors impede the regeneration of nerve cells. Two of the most important of these factors are the destabilization of the cytoskeleton and the development of scar tissue. While the former prevents regrowth of cells, the latter creates a barrier for severed nerve cells. Scientists of the Max Planck Institute of Neurobiology in Martinsried and their colleagues from the Kennedy Krieger Institute and University of Miami in the United States, and the University of Utrecht in the Netherlands, have now shown that the cancer drug Taxol reduces ...
2011-01-29
Plants are attacked by a multitude of insects and mammals. As defense against these herbivores they developed complex defense mechanisms over the course of evolution: spines, thorns, leaf hairs and a number of toxic chemical substances. For decades it has been controversially discussed whether the production of defense traits incurs costs to the plants. Now, using a new method the ecologists and plant biologists of the University of Zürich together with their American colleagues demonstrate these costs accurately in a Proceedings of the Royal Society article.
For their ...
2011-01-29
DETROIT – Light, or photodynamic, therapy can help preserve the voice and vocal cord function for patients with early stage laryngeal (voice box) cancer, according to a study from Henry Ford Hospital in Detroit.
"Photodynamic therapy is an effective treatment for early laryngeal squamous cell carcinomas, offering patients a less invasive option with fewer side effects than other therapies, while preserving the voice," says study co-author Vanessa G. Schweitzer, FACS, M.D., a senior staff physician in the Department of Otolaryngology-Head & Neck Surgery at Henry Ford. ...
2011-01-29
"Fathers transmit their smoking habits to a statistically significant level to their sons, and the same is true of mothers and daughters. However, if a mother smokes it does not seem to impact on the probability of her son smoking, and similarly a father that smokes does not affect his daughter", Loureiro, a researcher at the Universidade de Santiago de Compostela (USC), in Spain, and co-author of the study, tells SINC.
The research, which has been published in the journal Oxford Bulletin of Economics and Statistics, is based on information from the British Household ...
2011-01-29
Participating in community service activities and helping others is not just good for the soul; it has a healing effect that helps alcoholics and other addicts become and stay sober, a researcher from Case Western Reserve University School of Medicine reports.
In a review article published in the Volume 29 issue of Alcoholism Treatment Quarterly, Maria E. Pagano, PhD, associate professor of psychiatry at the School of Medicine, sheds light on the role of helping in addiction recovery, using the program of Alcoholics Anonymous (AA) as a prime example. She cites a growing ...
2011-01-29
ANN ARBOR, Mich.---DNA, that marvelous, twisty molecule of life, has an alter ego, research at the University of Michigan and the University of California, Irvine reveals.
On rare occasions, its building blocks "rock and roll," deforming the familiar double helix into a different shape.
"We show that the simple DNA double helix exists in an alternative form---for one percent of the time---and that this alternative form is functional," said Hashim M. Al-Hashimi, who is the Robert L. Kuczkowski Professor of Chemistry and Professor of Biophysics at U-M. "Together, these ...
2011-01-29
DETROIT – Using a novel surgical approach, it's possible to rebuild the trachea and preserve a patient's voice after removing an invasive throat tumor, according to a new report from Henry Ford Hospital in Detroit.
This case study is the first of its kind to not only document a successful technique to create a fully functional trachea, or windpipe, but also report a rare type of malignant tumor in an adult's trachea. Most commonly, this type of tumor is seen in newborns and very rarely occurs in the neck, says lead study author Samer Al-Khudari, M.D., with the Department ...
2011-01-29
Montreal, January 28, 2011 – The mystery began in 1976. Adolfo Pampena was diagnosed with a rare form of cancer that caused a strange combination of symptoms and was associated with the occurrence of multiple tumours in his stomach and colon. His medical team was stumped and was unable to answer the most important questions for him and his family: the cause of his disease and the risk for future generations.
Now, 35 years later, the answers are at hand thanks to a genetic study led by investigators at the Research Institute of the McGill University Health Centre (RI ...
LAST 30 PRESS RELEASES:
[Press-News.org] Hormone therapy begun at menopause may pose risk for breast cancer