Osteoporosis in Women With Cancer
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What Is Osteoporosis?
If you have osteoporosis, your bones become porous and weak. As they lose strength, they are more likely to break. People with osteoporosis are particularly at risk for breaking these bones.
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Spine
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Hip
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Wrist
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Pelvis
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Upper arm
If you have osteopenia, you also have bone loss, but not as much as with osteoporosis. People with osteopenia are more likely to develop osteoporosis if something is not done to stop the bone loss.
About 10 million Americans have osteoporosis. Another 34 million more have low bone mass, and that puts them at increased risk for osteoporosis. Cancer and some of its treatments can also increase your risk for osteoporosis.
How Does Osteoporosis Develop?
Bone is made of calcium and other minerals, which make it hard. Bone density refers to the mineral content of the bones. It is related to how hard and strong bones are. Low bone density is a trait of osteoporosis.
Like other tissues in the body, bone constantly repairs and renews itself. This process is called remodeling. Two kinds of cells carry out remodeling in bone.
A balance between the bone-building osteoblasts and the bone-dissolving osteoclasts keeps bones healthy.
In young people, bones lengthen and increase in density. After about age 35, however, a person’s bones start to lose density and strength. Most cases of osteoporosis result from the quicker bone loss, which occurs for any of these reasons.
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Decrease in hormone (estrogen and testosterone) levels in the body
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Lack of physical activity
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Lack of calcium and vitamin D
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Smoking
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Excessive alcohol use
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Certain medications
Osteoporosis is more common in women than in men. During menopause, estrogen production in a woman’s ovaries greatly slows down. This hormone keeps the bone-dissolving activity of the osteoclasts in check. After menopause, the osteoblasts continue to build bone. But they cannot keep up with the speed at which the osteoclasts break it down. As a result, a woman begins to lose bone rapidly, especially in the first 5 years after menopause. If you don’t take measures to prevent or slow bone loss, osteoporosis can occur.
In men, bone loss generally begins later. And it advances more slowly than it does in women. Men tend to have larger and stronger bones than women do. Plus, they do not go through the abrupt hormonal changes that occur with menopause. Still, as men age, they do lose bone density, in part because of a natural decrease in testosterone. By age 65 or 70, men and women lose bone mass at similar rates. Calcium absorption, which is needed to keep bones healthy, also decreases in men and women.
How Does Cancer Treatment Affect Bone Loss?
Certain cancer treatments can increase the risk for osteoporosis for both men and women. Some chemotherapy drugs used for breast cancer can cause a loss of bone density. Certain hormone therapies for breast and prostate cancer can, too. A number of strategies can help prevent and treat osteoporosis. Talk about these options with your healthcare team.
What Causes Osteoporosis in Women With Breast Cancer?
If you have breast cancer, you may be at higher risk for osteoporosis than other women. Here are some of the reasons why.
Early Menopause
Certain chemotherapy treatments used for breast cancer can cause the ovaries to stop making estrogen. That brings on menopause. Early menopause may also result when the ovaries are removed (oophorectomy). Or it can occur if you have radiation to your ovaries. These procedures are done to slow breast cancer growth because estrogen can cause some breast tumors to grow. However, the sudden lowering of estrogen levels also causes rapid bone loss.
Chemotherapy
Chemotherapy drugs such as Adriamycin (doxorubicin) and Rheumatrex or Trexall (methotrexate) can also prevent bone formation. And they cause a loss of bone density. They may cause menopause to happen earlier than usual. And that means bone loss starts earlier.
Hormone Therapies
In some breast cancers, the hormones estrogen and progesterone can speed up tumor growth. Hormone therapies are used to prevent this from happening, but can speed up bone loss, too. Hormone therapy may include ovary ablation or taking Nolvadex or aromatase inhibitors.
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Ovarian Ablation.The inactivation of the ovaries can occur with surgery to take out the ovaries, or it can occur when the ovaries are treated with radiation. For women who have not reached menopause, this can immediately bring about menopause and rapid bone loss. This is sometimes done in premenopausal women to decrease their breast cancer risk, or in women with breast cancer whose tumors grow in response to estrogen. It is also done in women with ovarian cancer.
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Aromatase inhibitors, such as Arimidex (anastrozole) and Femara (letrozole). This is a newer type of hormonal therapy. These drugs are used to treat postmenopausal women with breast cancer. Some studies suggest that these drugs may lead to a loss of bone density. Further research is needed to see if this is the case.
Can Osteoporosis Be Prevented or Treated in Women With Breast Cancer?
Have you had breast cancer and gone through menopause, either naturally or as a result of treatment? If so, you should consider having routine screenings for bone loss. A type of X-ray called the bone mineral density test is safe and noninvasive. It can do all these things.
Once bone is lost, it cannot be completely replaced using current types of treatment. Although it cannot be cured, osteoporosis can be slowed down. A number of approaches are available for preventing and treating osteoporosis in women.
Lifestyle Changes You Can Make
Here are some lifestyle approaches you can take to prevent bone loss.
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Get plenty of calcium and vitamin D. Calcium comes from the food we eat. Good sources include dairy products, such as milk, yogurt, and cheese. Some nondairy foods are also good sources, such as salmon, spinach, and tofu. Vitamin D comes from diet and the sun. The recommended daily intake of calcium is 1,000 mg for young to middle-aged adults and 1,500 mg for postmenopausal women older than age 50. The recommended daily dose of vitamin D is 400 to 800 IU.
Prescription Drugs That May Help
Here are some medical approaches you can use for preventing and treating bone loss.
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Bisphosphonates. These drugs prevent the breakdown of bone. The U.S. Food and Drug Administration (FDA) approved Actonel (risedronate) and Fosamax (alendronate) for preventing and treating osteoporosis in men and women. Both drugs are available as pills. They are well-tolerated and safe. The most common side effects include diarrhea, abdominal pain, and heartburn. Take the drug in the morning with 8 ounces of water at least 30 minutes before eating. Remain upright during this time to avoid gastrointestinal problems.
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Selective estrogen receptor modulators (SERMs). The FDA has approved Evista (raloxifene) for the prevention and treatment of osteoporosis. Researchers are also studying it as a potential drug to prevent breast cancer. If you’ve had breast cancer, discuss the use of raloxifene carefully with your medical oncologist. Researchers are continuing to learn about its effects on cancer and its interactions with other cancer treatments. Nolvadex (tamoxifen) is often prescribed as part of breast cancer treatment. It may help postmenopausal women maintain bone density during the standard 5 years of treatment.
Talk with your doctor to see if there are other treatments you should consider.