Posted on 02/05/2010 9:55:35 PM PST by neverdem
SAN ANTONIO — Two differently designed studies found a nearly identical, roughly 30% reduction in the risk of breast cancer in postmenopausal women who took bisphosphonates to prevent or remediate bone loss.
The results of a retrospective analysis of data from the Women's Health Initiative (WHI) in the United States and a case-control study conducted in Israel were presented at the annual San Antonio Breast Cancer Symposium.
In both studies, cancer incidence was sharply lower among women prescribed bisphosphonates for low bone mineral density, suggesting that the impact of these agents may extend beyond bone.
In the 151,592-patient database for the WHI, breast cancer development was explored only after controlling for baseline bone mineral density, since women at risk for osteoporosis are known to be at lower risk for breast cancer, likely due to a lower lifetime exposure to estrogen.
Following that statistical adjustment, researchers found that only 64 of 2,216 bisphosphonate users developed breast cancer after a mean 8 years of follow-up, and that 50 of the cancers were estrogen receptor–positive.
This represents a 32% lower incidence of breast cancer than was seen among non–bisphosphonate users, reported Dr. Rowan Chlebowski, a medical oncologist at the Harbor-University of California, Los Angeles Medical Center.
“This is a cohort study, not a definitive randomized, controlled trial, but I think it provides a strong signal,” said Dr. Chlebowski during a press conference preceding his podium presentation. “Oral bisphosphonate use may directly inhibit breast cancer incidence.”
No advantage was seen with respect to ductal carcinoma in situ (DCIS) in women taking bisphosphonates. Indeed, women taking bisphosphonates were slightly more likely to develop DCIS. This perhaps implies that the effects of bisphosphonates occur later in the development of breast cancer, Dr. Chlebowski said.
In Israel, women with breast cancer who reported taking bisphosphonates for at least a year prior to their diagnosis were matched to demographically similar women who were not taking bisphosphonates and without cancer. (Controls were selected by age, neighborhood, and ethnicity.) To ensure against recall bias, prescription records were used to confirm a prediagnosis history of bisphosphonate use, said Dr. Gad Rennert, chairman of community medicine and epidemiology at the Clalit National Cancer Control Center in Haifa, Israel.
Among the 4,575 subjects, those who took bisphosphonates for at least a year were 34% less likely to be diagnosed with breast cancer.
Risk reduction remained significant at 29% after controlling for other risk factors for breast cancer, including age, ethnicity, family history, fruit and vegetable intake, exercise, body mass index, pregnancy history, and use of calcium supplements and hormone replacement therapy.
“The tumors we saw were more commonly estrogen receptor–positive, and more precisely, strongly estrogen receptor–positive,” Dr. Rennert said during his podium presentation. “They were more commonly well differentiated.”
Both estrogen receptor positivity and cell differentiation are associated with response to treatment and a better prognosis.
Interestingly, no effect on breast cancer risk was seen in women who took bisphosphonates for less than a year, but after 1 year, the risk was reduced at a fairly steady rate. “Five years of use was not dramatically better than 4 years of use,” he said.
This finding corresponds with the drugs' pharmacokinetic profile, characterized by a slow and steady cumulative effect on bone that stabilizes after a period of time.
“We are seeing an association here. It's a very strong and robust association,” said Dr. Rennert.
Initially, a hint of cancer protection arose in small studies comparing breast cancer patients receiving bisphosphonates for cancer- and treatment-related bone loss to those who did not receive the drugs during treatment. The evidence seemed to show that those receiving the bone-protecting drugs also developed fewer new cancers in their contralateral breasts.
Possible biological explanations may lie in the ability of bisphosphonates to reduce angiogenesis and stimulate immune cells responsible for tumor cell detection, said Dr. Chlebowski during an interview.
Dr. Theresa Guise, professor of medicine and oncology at Indiana University, Indianapolis, said the studies may hold “very important implications for a large population of patients.”
The possibility that a “simple oral drug” could prevent both osteoporosis and breast cancer represents a “step forward in the prevention of … common health problems of women today,” she said at a press conference.
Dr. Chlebowski said that he has been a consultant for, or served on speakers bureaus for AstraZeneca, Novartis, Pfizer, Amgen, and Eli Lilly & Co. Dr. Rennert disclosed no relevant financial relationships.
Dr. Guise has been a consultant or served on speakers bureaus for Amgen, Novartis, Eli Lilly & Co., and Roche Pharmaceuticals.
etidronate (Didronel), pamidronate (Aredia), alendronate (Fosamax), risedronate (Actonel), zoledronate (Zometa or Reclast), ibandronate (Boniva)
Notice the terminal dronate in all of the generic names.
http://blogs.webmd.com/integrative-medicine-wellness/2008/10/strong-bones-for-life-naturally.html
“Even more frightening are recent studies conclusively linking bisphosphonate use with jaw osteonecrosis or bone death”
I took Fosamax almost 5 yrs and started getting terrible pains in my jaw. I researched it and found this warning - stopped immediately - 5 yrs ago. I still get the pain but much less often. Praying it will stop altogether.
I hope the pain stops. Prescribing a bisphosphonate now without warning about jaw pain and possible osteonecrosis of the jaw would be malpractice, IMHO.
Otherwise, I like drugs with more than one indication, e.g. alpha blockers for men with enlarged prostates and high blood pressure.
Thanks for the link.
ping
The Dozens of Computers That Make Modern Cars Go (and Stop)
Rice physicists kill cancer with 'nanobubbles'
Protein Supplement Myth Revealed by Body of Work
FReepmail me if you want on or off my health and science ping list.
Ok, this is just a buncha hooey. Less lifetime exposure = the osteoporosis kills you before the breast cancer gets you? But the incidence of diagnosis of breast CA is highest between ages of 30-40.
But thats an otherwise interesting finding - why does osteoP drop breast CA risk?
If you had bisphosphonate-induced osteonecrosis you would have a large hole in your mandible. It is not a simple problem causing pain, it melts your jaw bone. It is catastrophic.
You may have whats called a parafunctional habit - clenching or grinding your teeth at night. The clenching is particularly associated with head pain during the day. Like many carnivores humans have a profoundly strong set of choppers and can generate thousands of pounds of pressure in our bite.
So its a low probability that its the bisphosphonates that are causing the pain. Unless you can brush without opening your mouth!
Try some vitamin D3 + vitamin K2 (preferably MK4) to strengthen bone. Hopefully that should help your jaw.
both my CHF and osteo have improved so much in the past 5 years that my doctor scratches his head...and I can get up out the tub with no problems and no assistance now. Thank goodness, for I do love my chin-deep tubbies.
ah, but does it decrease breast cancer?
Estrogen prevents osteoporosis, so women with a lot of estrogen (e.g. the obese) are less likely to use these medicines.
On the other hand, estrogen is associated with breast cancer.
I used to tell my women: Which do you want: a hip fracture at 78 or breast cancer?
Having "jaw pain" without these profound signs and symptoms is not indicative bisphosphonate induced osteonecrosis.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.