by columnist Paul Sieber, MD
Osteoporosis and prostate cancer are terms not often used in the same sentence. However, more and more attention is being paid to what was once viewed primarily as a women’s disease.
What is osteoporosis?
Osteoporosis involves a loss of bone or bone density that puts one at increased risk for fractures, particularly of the hip and for compression fractures of the spine.
The risk of osteoporosis is felt to be two-four times greater in women than in men. In women, the condition is probably secondary to the loss of estrogen that occurs at menopause and is more pronounced because women have less dense bone than men. However, certain diseases put men at an increased risk for bone loss over women. The treatment of prostate cancer with anti-testosterone medications, such as Lupron and Zoladex, mimics the loss of estrogen in women at menopause. With more common use of early hormonal therapy for prostate cancer, the problem will most certainly increase in men. Other factors can also cause osteoporosis including treatment with such steroids as prednisone, as well as thyroid and parathyroid conditions. Smoking, alcohol, and a sedentary lifestyle can also contribute to the problem.
How is osteoporosis diagnosed?
The diagnosis of osteoporosis is made with an X-ray. The most common and accurate bone study is through a type of X-ray called a DEXA scan (Dual Energy X-ray Absorptiometry.) This type of scan is very safe and takes about ten minutes to do. The patient lies flat on a table while a scanner moves over the body measuring bone density at two different spots, usually the hip (or thigh bone) and lower spine. Although there is no current standard for bone density in men, surprisingly, the standard now used for women is felt to be accurate enough for men. The results of the DEXA scan are given as a “T-score” which represents the degree of deviation from the normal bone scan reading of a 21 year-old woman. A score of -1.0 to -2.5 is considered osteopenia while a score below -2.5 is characterized as osteoporosis.
Treatments For Osteoporosis
Once the degree of bone loss is determined, various treatments are available for increasing bone density. For milder cases, called osteopenia, the treatments include cessation of smoking, a regular program of weight-bearing exercise and increasing calcium and vitamin D intake. For severe cases, called osteoporosis, the treatment is less well defined for men. For men with prostate cancer, however, the restoration of testosterone is not advisable. The bisphosphonate, Fosamax, is usually prescribed, yet little research on its efficacy in men with prostate cancer has been done.
Two new treatment options have recently been reported. One involves the use of Casodex, a drug that is currently approved for use in conjunction with Lupron or Zoladex. When used alone as monotherapy, however, it causes no loss of bone density. It is currently approved in fifty countries as monotherapy, but has not yet been approved in the U.S. for this use.
A second new treatment involves a very potent bisphosphonate, Zometa. It is currently approved for use in advanced hormone-refractory prostate cancer but it has also shown promise in reversing osteoporosis in men receiving Lupron or Zoladex.
Prevention of Osteoporosis in Prostate Cancer Patients
The patient with prostate cancer should talk with his doctor about screening for osteoporosis. Early diagnosis is important to prevent a long-term problem. More research is sorely needed in this area and most urologists are just now hearing about osteoporosis in prostate cancer patients. This means that patients need to be proactive in investigating all treatment options. The new drugs mentioned above appear promising in terms of treating this often-overlooked condition.
References
Ross, Robert and Small, Eric: Osteoporosis in Men Treated with Androgen Deprivation Therapy for Prostate Cancer. Journal of Urology,167:1952-1956, May, 2002.
Berruti, Alfred et al. Metabolic Bone Disease Induced by Prostate Cancer; Rationale for the use of Bisphosphonates. Journal of Urology,166:2023-2031,December2001
Sieber, Paul et al., Bone Mineral Density is Maintained during Biclutamide" Casodex" Treatment, Presentation American Society Clincal Oncologists (ASCO) 38th Annual Meeting May18-21, Orlando,Florida
Posted September 2002
Updated November 2009
