Doc: Bone loss may result from breast cancer drug use

Dear Dr. Roach: I am a 69-year-old female breast cancer survivor. I’ve been taking Arimidex for five years, and plan to continue for another five. Through the years, my bone density scans have been normal, up until this year. I’m now on the edge of osteopenia. My oncologist now recommends Prolia. After reading about the possible side effects, I am very hesitant to receive the injection. I feel like, at this point in life, I should just take my chances on the possibility of breaking a bone rather than expose myself to potential harm from Prolia. I’ve started daily vitamin D, as well as increased calcium intake from food, rather than supplements.

What are your thoughts on this drug?

C.R.

Dear C.R.: Anastrozole (Arimidex) is an aromatase inhibitor: It works by preventing the body from converting androgens from the adrenal glands to estrogens, which are female hormones that encourage some breast cancers to grow. However, estrogens also help keep bones strong, so it is common for post-menopausal women on anastrozole to develop bone loss leading eventually to osteopenia and finally to osteoporosis. AIs like anastrozole increase the risk for hip fracture. A hip fracture is a major health risk: One-year mortality rates after hip fracture range from 14 percent to 58 percent. Preventing a hip fracture is critically important.

In osteoporosis, treatment with denusomab (Prolia) or bisphosphonates generally has more benefits than risks. I normally recommend against the use of these drugs in women with osteopenia; however, in women taking anastrozole, it is reasonable to consider the use of denosumab or a bisphosphonate in women with severe osteopenia or in those in whom the bone density is dropping rapidly. It doesn’t sound like that is the case in you. However, you may have more risk factors for fracture than I know of, which may be why your oncologist is recommending treatment.

I agree with the calcium intake, given your low bone density, and vitamin D supplementation may be appropriate if your vitamin D level is low or if you have additional risk. Any exercise is of benefit: Yoga and tai chi have been shown to be beneficial. However, weight-bearing exercises, especially higher-impact exercises, are even better for preventing bone loss.

Dear Dr. Roach: I have a 65-year-old friend who says a doctor told her that she doesn’t have a particular marker in her blood and that if a person doesn’t have this marker, they will never get colon cancer. Is this true?

K.

Dear K.: It would be great if it were, but as of today, there are no blood tests for colon cancer that are reliable enough to use for screening. Colonoscopy remains the most frequently used and probably the best tool for colon cancer screening.

Email questions to ToYourGoodHealth@med.cornell.edu.