Osteoporosis is a condition of low bone mass and low bone density. As a result, bones are thin and weak and at higher risk for fracture. The spine, wrist, and hip are the most susceptible to fracture. Osteoporosis usually does not cause symptoms, but any of the following may be a sign of the condition:

  • Weight loss
  • Stooped posture
  • Curving of the upper back
  • Bone tenderness
  • Loss of 1-2 inches in height

Causes of Osteoporosis

Osteoporosis often occurs in older women, because the loss of estrogen after menopause can cause a decrease in bone density. All women should consider those factors that increase the risk for osteoporosis. These risk factors include older age, family history of osteoporosis, smoking, low body weight, or a history of broken bones and chronic treatment with cortisone-like drugs. If you have any of these risk factors, your doctor will follow you closely to make sure that your bone density is sufficient.

For women with breast cancer, the risk of osteoporosis is increased when treatment causes early menopause. In addition, many breast cancer treatments increase the risk for osteoporosis, including some chemotherapy drugs, aromatase inhibitors (anastrozole [Arimidex], exemestane [Aromasin], and letrozole [Femara]), and surgical removal or chemical suppression (goserelin [Zoladex], leuprolide [Lupron]) of the ovaries.

Diagnosis of Osteoporosis

Osteoporosis is usually diagnosed with use of a bone mineral density test. The test most often used is a specialized low-dose x-ray technique known as dual-energy x-ray absorptiometry, commonly referred to as densitometry or a DEXA scan. This test calculates bone density according to how much radiation is absorbed by the bone. Osteoporosis is indicated by a bone density lower than the range expected in premenopausal women or other women similar to you in terms of age and ethnicity. Bone mineral density testing is noninvasive, is not painful, and takes about 20-30 minutes to complete.

If you are at risk for osteoporosis or will be receiving breast cancer treatment that increases your risk for osteoporosis, your doctor may request bone mineral density testing before treatment begins, to obtain a baseline value for later comparison.

Management of Osteoporosis

Adopting a few lifestyle habits can help keep bones strong. The most important habit is to take a sufficient amount of calcium and vitamin D (which helps bone absorb calcium). The American Society of Clinical Oncology (ASCO) recommends that women with breast cancer get 1,200 mg of calcium and 400-800 U of vitamin D each day. Calcium and vitamin D can be taken as supplements as well as obtained through certain foods (Table 1). A few minutes in sunlight also helps the body make vitamin D. ASCO recommends regular weight-bearing exercise and avoidance of smoking as additional ways to prevent osteoporosis.

Several drugs have been approved for the prevention/treatment of osteoporosis: alendronate sodium (Fosamax), risedronate (Actonel), ibandronate (Boniva) and zoledronic acid (Reclast). Fosamax and Actonel are oral medications that are taken daily or weekly. Boniva can be taken orally once a month or be given as an injection once every 3 months. Reclast is given as a yearly intravenous injection. These drugs are usually prescribed to prevent osteoporosis in women at high risk for the condition or women who have a score of at least -2.5 on DEXA scanning. Estrogen therapy and combined estrogen and progestin therapy (by mouth or as a patch) are approved for prevention of osteoporosis. Another drug, raloxifene (Evista), has been effective in some women, but it is not recommended for women who have already taken tamoxifen for 5 years. Calcitonin (Miacalcin) is used for treating postmenopausal bone loss and is administered as a nasal spray or injection. Teriparatide (Forteo) is a form of parathyroid hormone approved for treatment of osteoporosis in postmenopausal women. You should discuss prevention and treatment options with your oncologist or your primary doctor, or both.

Some complementary and herbal supplements are marketed as agents to help prevent and/or treatment osteoporosis, but none has been found to be effective in clinical trials in humans. Be sure to talk to your oncologist before taking any supplements.

As you are followed up after breast cancer treatment, be sure to have routine bone density testing to ensure that osteoporosis, if present, can be detected early.

Table 1. Ways to Decrease Risk of Osteoporosis

Include enough calcium and vitamin D in your diet
Calcium:     Dairy products (low-fat milk,
                      yogurt, and cheese )
                    Calcium-fortified orange juice
                    Dark green leafy vegetables
                      (broccoli, spinach, collard
                      greens, bok choy)
                    Vitamin-fortified cereal
                   Calcium supplement
Vitamin D:   Vitamin D-fortified milk
                    Herring, salmon, tuna
                    Vitamin-fortified cereal
Engage in weight-bearing exercise and/or strength training (3-4 times per week for maximum benefit)
Walking, jogging, tennis (or other racket sports), dancing, lifting weights, yoga
Minimize the risk of falls
Use hand rails on stairs and in bathroom
Ensure sufficient lighting around the
Secure or remove throw rugs
Use a cane or walker if necessary
Don’t be afraid to ask for help walking
Drink little or no alcohol  
Avoid smoking