Several breast cancer treatments can cause bone loss, also called osteopenia or osteoporosis:
- aromatase inhibitors (a hormonal therapy)
- ovary removal or medical shutdown
Still, a very small study found that more than 75% of 64 postmenopausal women diagnosed with breast cancer with bone loss had factors besides breast cancer treatment that could contribute to bone loss:
- Low levels of vitamin D. Along with calcium, vitamin D plays a critical role in maintaining bone health.
- A condition called indiopathic hypercalciuria. This means the kidneys get rid of too much calcium in the urine, causing calcium levels to drop and affect bone health.
- Hyperparathyroidism. In this condition, the parathyroid glands (very tiny glands underneath the thyroid glands in the neck) produce too much parathyroid hormone. The parathyroid hormone affects blood calcium levels by driving calcium out of the bones, causing bone loss over time.
These same factors were seen in the women in the study who had bone loss but weren't treated for breast cancer.
Because these causes of bone loss are treatable, the researchers suggest that women with bone loss during and after breast cancer treatment be evaluated carefully for ALL possible causes of bone loss.
When you're being treated for breast cancer, it might seem like everything affecting your health is related to the breast cancer or its treatment. That's understandable. Still, it's important for you and your doctor to keep an eye on the whole, big picture of your health, including bone health. If you're told that you have bone loss during or after treatment, ask your doctor if ALL the possible causes of bone loss have been considered, including causes not related to cancer treatment. While the bone health effects of breast cancer treatment may not be completely avoidable, other factors that can be treated may be contributing to your bone loss. But these factors can be treated only if they're diagnosed.
The Bone Health section of Breastcancer.org offers detailed information on bone health, how bone health is measured, and how breast cancer treatments can affect bone health, as well as tips to keep your bones as strong as they can be.