 |
|
Dense Breasts, Hormone Levels Are Two Separate, Independent Risk Factors For Breast Cancer
August 21, 2007Washington, D.C.--The density of a woman's breast tissue and her level of sex hormones are two strong and independent risk factors for breast cancer, according to a team of researchers from Harvard and Georgetown universities. The finding dispels the common belief that the risk associated with dense breasts merely reflects the same risk associated with high levels of circulating sex hormones, they say.
Their study, published in the August 1 issue of the Journal of the National Cancer Institute, found that the relative risk of developing breast cancer in post-menopausal woman with dense breasts was 400 percent higher than in women with fatty, non-dense breast tissue, and that high versus low levels of hormones (estrogen and testosterone) increased the relative risk by 200 percent. Adjusting for a woman's circulating hormone levels did not reduce the risk associated with the level of breast density. Furthermore, these independent risk factors seemed to have additive effects so if a woman had both dense breasts and excess hormones, her risk was increased by 600 percent, the researchers found.
"We have found that dense breasts are not a marker for higher hormone levels, or vice versa, and this tells us each increases breast cancer risk via a different biochemical pathway," said co-author Celia Byrne, Ph.D., an assistant professor in the Lombardi Comprehensive Cancer Center at Georgetown University Medical Center. Byrne designed and conducted the study while she was an instructor of medicine at Harvard Medical School. The study's three other authors, including the corresponding author, Rulla Tamini, Sc.D., were from Harvard.
Women at risk should pay attention to these early findings, even though they need to be confirmed and studied further, Byrne added. "Women who know they have dense breasts should make sure they have regular mammograms," she said. Women usually don't know if they have dense breast tissue and the best way to find out is through a digital mammogram, she explained. Additionally, post-menopausal women who are overweight can reduce their blood hormone levels by decreasing body fat, Byrne added, since fat itself is converted by the body to estrogen.
The findings represent an opportunity to both fine-tune existing breast cancer risk models, which, thanks to research by Byrne and her colleagues, now include breast density to help estimate a woman's risk. But the model does not take into account hormone level, Byrne said. "If we could find out what causes breast tissue to be dense, and how that increases breast cancer risk, then we might have a new opportunity to help women lower their risk," she said.
Byrne said she was surprised at the findings. "Our assumption was that this study would confirm what everyone had believed ? that hormone levels explain breast density." This presumption of an association between hormone levels and breast density was based on "the circumstantial evidence, such as the fact that during pregnancy, when hormones increase, breasts also grow in size," she said. "But that is not what our study showed."
In a 1995 study, Byrne and her colleagues discovered that women whose breasts contain at least 75 percent dense tissue are at a four- to six-fold greater risk of breast cancer than women with entirely fatty breasts (no measurable dense tissue). Recent research has suggested that having dense breast tissue may be partially an inherited genetic trait. Other recent studies have indicated that for women with dense breast digital mammography may be more effective for screening.
In this study of 773 postmenopausal women who participated in Harvard's Nurses Health Study ?253 who had breast cancer and 520 who didn't ? the researchers evaluated hormones in their blood and measured breast density using a computer-assisted analysis of mammograms. None of the women were using hormone replacement therapy (HRT) at the time they were evaluated.
There are several theories as to why dense breasts might increase a woman's risk of developing breast cancer, Byrne said. One is that dense tissue has more epithelial cells than breasts that are not dense, and thus more possibilities exist that one or more of these cells will become cancerous. Another is that there is more "cross-talk" between the stromal cells in the breast, which produce a variety of hormones and growth factors, and epithelial cells in the tissue, which is where most breast cancer develops. The third is a combination of the first two theories, she said.
Much more work needs to be done to understand why breast density would increase breast cancer risk, the researchers wrote, and they noted that further studies should measure hormone levels directly within breast tissue, not indirectly through blood, as they chose to do in this first investigation.
Byrne received funding to conduct this study from the National Cancer Institute, and the other co-authors received funding from the Breast Cancer Research Fund, and the American Cancer Society. Other authors include Graham Colditz M.B.B.S., Dr.Ph. now Adjunct Professor at Washington University in St. Louis, and Susan Hankinson, Sc.D, the principal investigator of the Nurses' Health Study.
About Lombardi Comprehensive Cancer Center
The Lombardi Comprehensive Cancer Center, part of Georgetown University Medical Center and Georgetown University Hospital, seeks to improve the diagnosis, treatment, and prevention of cancer through innovative basic and clinical research, patient care, community education and outreach, and the training of cancer specialists of the future. Lombardi is one of only 39 comprehensive cancer centers in the nation, as designated by the National Cancer Institute, and the only one in the Washington, DC, area. For more information, go to http://lombardi.georgetown.edu.
About Georgetown University Medical Center
Georgetown University Medical Center is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through our partnership with MedStar Health). Our mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis -- or "care of the whole person." The Medical Center includes the School of Medicine and the School of Nursing and Health Studies, both nationally ranked, the world-renowned Lombardi Comprehensive Cancer Center and the Biomedical Graduate Research Organization (BGRO), home to 60 percent of the university's sponsored research funding.
Georgetown University Medical Center
Women at risk should pay attention to these early findings, even though they need to be confirmed and studied further, Byrne added. "Women who know they have dense breasts should make sure they have regular mammograms," she said. Women usually don't know if they have dense breast tissue and the best way to find out is through a digital mammogram, she explained. Additionally, post-menopausal women who are overweight can reduce their blood hormone levels by decreasing body fat, Byrne added, since fat itself is converted by the body to estrogen.
The findings represent an opportunity to both fine-tune existing breast cancer risk models, which, thanks to research by Byrne and her colleagues, now include breast density to help estimate a woman's risk. But the model does not take into account hormone level, Byrne said. "If we could find out what causes breast tissue to be dense, and how that increases breast cancer risk, then we might have a new opportunity to help women lower their risk," she said.
Byrne said she was surprised at the findings. "Our assumption was that this study would confirm what everyone had believed ? that hormone levels explain breast density." This presumption of an association between hormone levels and breast density was based on "the circumstantial evidence, such as the fact that during pregnancy, when hormones increase, breasts also grow in size," she said. "But that is not what our study showed."
In a 1995 study, Byrne and her colleagues discovered that women whose breasts contain at least 75 percent dense tissue are at a four- to six-fold greater risk of breast cancer than women with entirely fatty breasts (no measurable dense tissue). Recent research has suggested that having dense breast tissue may be partially an inherited genetic trait. Other recent studies have indicated that for women with dense breast digital mammography may be more effective for screening.
In this study of 773 postmenopausal women who participated in Harvard's Nurses Health Study ?253 who had breast cancer and 520 who didn't ? the researchers evaluated hormones in their blood and measured breast density using a computer-assisted analysis of mammograms. None of the women were using hormone replacement therapy (HRT) at the time they were evaluated.
There are several theories as to why dense breasts might increase a woman's risk of developing breast cancer, Byrne said. One is that dense tissue has more epithelial cells than breasts that are not dense, and thus more possibilities exist that one or more of these cells will become cancerous. Another is that there is more "cross-talk" between the stromal cells in the breast, which produce a variety of hormones and growth factors, and epithelial cells in the tissue, which is where most breast cancer develops. The third is a combination of the first two theories, she said.
Much more work needs to be done to understand why breast density would increase breast cancer risk, the researchers wrote, and they noted that further studies should measure hormone levels directly within breast tissue, not indirectly through blood, as they chose to do in this first investigation.
Byrne received funding to conduct this study from the National Cancer Institute, and the other co-authors received funding from the Breast Cancer Research Fund, and the American Cancer Society. Other authors include Graham Colditz M.B.B.S., Dr.Ph. now Adjunct Professor at Washington University in St. Louis, and Susan Hankinson, Sc.D, the principal investigator of the Nurses' Health Study.
About Lombardi Comprehensive Cancer Center
The Lombardi Comprehensive Cancer Center, part of Georgetown University Medical Center and Georgetown University Hospital, seeks to improve the diagnosis, treatment, and prevention of cancer through innovative basic and clinical research, patient care, community education and outreach, and the training of cancer specialists of the future. Lombardi is one of only 39 comprehensive cancer centers in the nation, as designated by the National Cancer Institute, and the only one in the Washington, DC, area. For more information, go to http://lombardi.georgetown.edu.
About Georgetown University Medical Center
Georgetown University Medical Center is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through our partnership with MedStar Health). Our mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis -- or "care of the whole person." The Medical Center includes the School of Medicine and the School of Nursing and Health Studies, both nationally ranked, the world-renowned Lombardi Comprehensive Cancer Center and the Biomedical Graduate Research Organization (BGRO), home to 60 percent of the university's sponsored research funding.
Georgetown University Medical Center
Breast Cancer Current Events and Breast Cancer News RSSStudy identifies causes of bone loss in breast cancer survivors
Osteoporosis is a growing concern among breast cancer survivors and their doctors, because certain cancer drugs can cause bone loss.
2 new compounds show promise for eliminating breast cancer tumors
Two new compounds created by a University of Central Florida professor show early promise for destroying breast cancer tumors.
UNC researchers find clue to stopping breast-cancer metastasis
If scientists knew exactly what a breast cancer cell needs to spread, then they could stop the most deadly part of the disease: metastasis. New research from the University of North Carolina at Chapel Hill School of Medicine takes a step in that direction.
Fear, misconceptions about screenings keep many African-Americans from getting mammograms
Training physicians and caregivers to improve cultural sensitivity and communication with economically disadvantaged African-American patients could influence these women to get mammograms that could save their lives.
New technology could revolutionize breast cancer screening
The world's first radar breast imaging system developed at Bristol University that could revolutionise the way women are scanned for breast cancer, is being trialled at North Bristol NHS Trust (NBT).
Battling bacteria in the blood: Researchers tackle deadly infections
It's a leading cause of death, but no one knows for sure how and why it happens. It's a major source of health care costs, adding days or weeks to the hospital stays and lost work time of millions of people. But no one fully understands how best to fight it.
Mayo Clinic Study Finds Risk Assessment Tool Not Reliable Predictor for Some Women at High Risk of Breast Cancer
A statistical model commonly used to predict the risk of breast cancer in women was not accurate when used to evaluate women with atypical hyperplasia, according to a new Mayo Clinic study published in the Oct. 14, 2008, issue of the Journal of Clinical Oncology.
Migraines associated with lower risk of breast cancer
Women who suffer from migraines may take at least some comfort in a recent, first-of-its-kind study that suggests a history of such headaches is associated with a significantly lower risk of breast cancer.
Folic acid, B vitamins do not appear to affect cancer risk
A daily supplementation combination that included folic acid and vitamin B6 and B12 had no significant effect on the overall risk of cancer, including breast cancer, among women at high risk of cardiovascular disease, according to a study in the November 5 issue of JAMA.
Healthy bones program reduces hip fractures by 37 percent
Proactive measures can reduce hip fracture rates by an average of 37.2 percent -- and as much as 50 percent -- among those at risk, according to a study conducted by Kaiser Permanente Southern California. The study was published online on November 3 by The Journal of Bone & Joint Surgery, a peer-reviewed journal.
More Breast Cancer Current Events and Breast Cancer News Articles
 | Breast Cancer Husband : How to Help Your Wife (and Yourself) during Diagnosis, Treatment and Beyond by Marc Silver A unique guide, like none other on the market-packed with medical information, practical tips, psychological insight, and coping strategies-to help men help the women they love through this trying time. When Marc Silver became a breast cancer husband three years ago, he learned firsthand how frightened and helpless the breast cancer husband feels. He searched in vain for a book that would give... |
 | Chicken Soup for the Breast Cancer Survivor's Soul: Stories to Inspire, Support and Heal (Chicken Soup for the Soul) by Jack Canfield, Mark Victor Hansen, Mary Olsen Kelly Your support group in a book, filled with boundless strength and profound hope - until the fight is won. Along with the shock, fear and loss many women face upon a breast cancer diagnosis comes unexpected strength, wisdom, and strong networks of sharing, support and healing. In Chicken Soup for the Breast Cancer Survivor's Soul, survivors and their family members talk openly about how difficult... |
 | Choices in Breast Cancer Treatment: Medical Specialists and Cancer Survivors Tell You What You Need to Know (A Johns Hopkins Press Health Book) A diagnosis of breast cancer can be overwhelming. The disease is frightening and the medical landscape confusing. In the wake of fear and confusion comes the need to make decisions about treatment. This book provides women with medically reliable and up-to-date information to help them with these decisions.Within these pages is a team of private consultants -- including surgeons, medical... |
 | The Breast Cancer Survivor's Fitness Plan (Harvard Medical School Guides) by Carolyn M. Kaelin, Francesca Coltrera, Josie Gardiner, Joy Prouty The only breast cancer recovery program designed by a Harvard doctor and survivor and approved by the American Council on Exercise (ACE) Feel healthy again. Regain control of your life. Exciting new research reveals that regular exercise can reduce the chance of breast cancer recurrence and extend your life. Exercise can also help you recover energy, strength, and flexibility diminished by... |
 | Breast Cancer Survival Manual, Fourth Edition: A Step-by-Step Guide for the Woman With Newly Diagnosed Breast Cancer by John Link A completely updated edition of the definitive guide for patients with breast cancer The new fourth edition of The Breast Cancer Survival Manual provides essential updates on treatment and care, enhancing the basic information that has made this the most trusted guide for women diagnosed with breast cancer for the past decade. This edition includes the most current advice on • getting a second... |
 | What Your Doctor May Not Tell You About(TM): Breast Cancer: How Hormone Balance Can Help Save Your Life (What Your Doctor May Not Tell You About...) by John R. Lee, David Zava, Virginia Hopkins An informative and absorbing read for both medical practitioners and their patients, What Your Doctor May Not Tell You About Breast Cancer takes aim at "the breast cancer industry" with a barrage of thought-provoking ammunition. The book is equal parts criticism and suggestion. Current health treatments, including HRT, receive serious condemnation, and authors John Lee and David Zava carefully... |
 | Breast Cancer: Real Questions, Real Answers by David Chan Breast Cancer: Real Questions, Real Answers is an outgrowth of Dr. David Chan's more than 20 years in private oncology practice. Inspired by his patients—who courageously face their illness but often feel fearful, confused about their options, and full of questions—Dr. Chan's book is uniquely structured as a Question and Answer between patient and doctor. It provides readers with an easily... |
 | I Am Not My Breast Cancer: Women Talk Openly About Love and Sex, Hair Loss and Weight Gain, Mothers and Daughters, and Being a Woman with Breast Cancer by Ruth Peltason I Am Not My Breast Cancer gathers the warm, loving, frank, and informed voices of more than eight hundred women—from every state in the nation and from continents as far away as Australia and Africa—who reveal their fears, trade advice, share experiences, and express their deepest, most intimate concerns. Essential reading for any woman with this diagnosis, it offers the companionship of... |
 | The Breast Cancer Prevention Diet: The Powerful Foods, Supplements, and Drugs That Can Save Your Life by Dr. Bob Arnot "From one of the most visible and highly respected figures in medical journalism comes a book that can literally save lives. During the past several years, doctors at leading institutions across the nation have been investigating the relationship between breast cancer and diet. The recent flood of medical studies confirm that what a woman eats can have a dramatic impact on whether or not... |
 | Living Through Breast Cancer - PB by Carolyn M. Kaelin Winner of two prestigious American Medical Writers Association awards A compassionate guide to surviving breast cancer from a doctor who has experienced it from both sides of the stethoscope In addition to being a leading national breast cancer expert and a highly respected cancer surgeon, Dr. Carolyn Kaelin also is a breast cancer survivor. In Living Through Breast Cancer she draws upon her... |
| © 2008 BrightSurf.com |