Bone Loss from Chemotherapy

A new study has found that a surprising number of women undergoing chemotherapy may be experiencing a rapid and significant decline in bone density.

Writing in the Journal of Clinical Oncology, Dr. Charles Shapiro of Ohio State University and colleagues reported that spinal bone density appears to decline at an alarming rate-up to 8 percent in pre-menopausal women after 12 months of treatment.

Shapiro's team assessed the spinal bone density of 49 women, median age 42, near the start of their chemotherapy regimen. Thirty-five of the women (71 percent) soon entered pre-mature menopause as a result of their treatment. The extent of bone loss that these women experienced in such a short period of time surprised the researchers; in normal post-menopausal women, the rate of bone loss in the spine is approximately 1 - 2 percent a year.

Chemotherapy causes the ovaries to suddenly stop producing estrogen. Among its other functions, estrogen protects the bones from deteriorating. All women gradually stop producing estrogen as part of the natural menopause process. However, with chemotherapy, the decline in estrogen production is much more rapid-causing a pronounced loss of bone density as a result.

"Chemotherapy-induced ovarian failure causes rapid and highly significant bone loss in the spine," they wrote. "This may have implications for long-term breast cancer survivors who may be at higher risk for osteopenia, and subsequently osteoporosis."

As a result of their findings, the researchers cancelled the second part of the study in which women were to receive either a calcium nasal spray or a placebo.

Shapiro's team will soon begin a clinical trial for bisphosphonate zolendronic acid (Zometa) to see if it has a benefit in minimizing bone density loss in women undergoing chemotherapy. In the interim, they urged that more women undergoing chemotherapy have their bone density, calcium and vitamin D intake checked on a regular basis.

"Women with breast cancer who develop chemotherapy-induced ovarian failure should have their bone density monitored and treatment to attenuate [minimize] bone loss should be evaluated," they recommended.

(It is of importance to note that 2/3s of the patients who were in this study had received CMF chemotherapy regimen, which is more likely than AC to result in premature menopause. This study also was not a long term study, therefore there may some patients who will resume menses again over time. A bone density measurement is a smart test to consider for women experiencing chemo-related menopause.)

SOURCE:
Journal of Clinical Oncology, July 15, 2001; 19(14):3306-3311

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