Changes in bone mineral density in women with breast cancer receiving aromatase inhibitor therapy

Marilyn L. Kwan1 · Song Yao2 · Cecile A. Laurent1 · Janise M. Roh1 · Charles P. Quesenberry Jr.1 · Lawrence H. Kushi1 · Joan C. Lo1. Breast Cancer Research and Treatment, December 2017

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Changes in bone mineral density in women with breast cancer receiving aromatase inhibitor therapy

Marilyn L. Kwan1 · Song Yao2 · Cecile A. Laurent1 · Janise M. Roh1 · Charles P. Quesenberry Jr.1 · Lawrence H. Kushi1 · Joan C. Lo1. Breast Cancer Research and Treatment, December 2017

Purpose We assessed bone mineral density (BMD) change with aromatase inhibitor (AI) treatment in a contemporary cohort of women with breast cancer treated in Kaiser Permanente Northern California.

Methods Percent and estimated annual percent changes in BMD at the total hip and lumbar spine were examined in 676 women receiving AI therapy who had two serial BMD reports available (at least 1 year apart) before and after AI initiation (N = 317) or during continued AI therapy (N = 359). BMD changes were examined at the total hip and lumbar spine and compared by age and clinical subgroups.

Results Women experienced BMD declines after AI initiation or continued therapy, with median annual percent change − 1.2% (interquartile range, IQR − 2.4 to − 0.1%) at the hip and − 1.0% (IQR − 2.3 to 0.1%) at the spine after AI initiation, and − 1.1% (IQR − 2.4 to 0.1%) at the hip and − 0.9% (IQR − 2.4 to 0.5%) at the spine during continued therapy. Higher levels of bone loss were observed among younger (< 55 years) compared with older (≥ 75 years) women at the hip (− 1.6% vs. − 0.8%) and at the spine (− 1.5% vs. − 0.5%) after AI initiation, and at the hip (− 1.4% vs. − 1.2%) and at the spine (− 2.4% vs. − 0.001%) during continued therapy.

Conclusions Small but consistent declines in total hip and lumbar spine BMD were present in breast cancer patients following AI therapy initiation or continued AI therapy. Although the overall rates of osteoporosis were low, greater estimated levels of annual bone loss were evident among women < 55 years.

Main findings

  • Large sample size of 676 women.
  • Those that took Aromatase inhibitors (AI) observed an average overall 3% decrease in total hip bone mineral density (BMD) with an estimated average annual BMD loss of 1%, along with an average overall 2% decrease in lumbar spine BMD with an estimated average annual BMD loss of 1%.
  • Higher rates of bone loss were evident among younger women under age 55 years, particularly in the spine after AI initiation.
  • These findings have implications for clinical management and suggest that clinicians caring for breast cancer patients should be aware that younger women may experience greater bone loss compared to older women when on an aromatase inhibitor, and appropriate screening and preventive measures should be implemented prior to and during treatment.