Aromatase inhibitor treatment in breast cancer is associated with accelerated bone loss and an increased risk of fracture. Bisphosphonates (BPs) are the mainstay treatment of aromatase inhibitor-associated bone loss (AIBL), which might improve femoral bone at key locations prone to fracture. To test this hypothesis, we performed three-dimensional cortical bone mapping based on quantitative computed tomography (QCT) scans in postmenopausal women with early breast cancer who were receiving aromatase inhibitors. Data of subjects who had both baseline and at least one follow-up QCT at Severance Hospital (South Korea) between 2005 and 2015 were analyzed (BP users, n = 93; BP non-users, n = 203). After exclusion of BP users with low medication persistence (proportion of days covered: <50%), BP users and non-users were 1:1 matched (n = 54 for each group) in terms of age, lumbar spine volumetric bone mineral density (LSvBMD), femoral neck areal BMD (FNaBMD), and total hip areal BMD (THaBMD). During a median follow-up of 2.1 years, BP use attenuated bone loss in LSvBMD (+7.2% vs. −3.8%, p < 0.001), FNaBMD (+1.3% vs. −2.7%, p < 0.001), and THaBMD (-0.3% vs. −2.5%, p = 0.024). BP had a protective effect on cortical parameters of femoral bone: estimated cortical thickness (CTh) (+3.3% vs. + 0.1%, p = 0.007) and cortical mass surface density (CMSD, cortical mass per unit surface area was calculated by multiplying cortical BMD with CTh) (+3.4% vs. −0.3%, p < 0.001). CMSD increased by up to 15% at key locations such as the superior part of the femoral neck and greater trochanter. BP prevented the thinning of average CTh of the femoral neck (-1.4% vs. −6.1%, p < 0.001), particularly at the superior anterior quadrant of femoral neck (absolute difference: +12.8% point vs. non-users). Compared to BP non-users, BP users had improved cross-sectional moment of inertia (+4.4% vs. −0.7%, p = 0.001) and less increase in buckling ratio (+1.3% vs. + 7.5%, p < 0.001). In summary, BP use prevented cortical bone deficits observed in AIBL at key locations of the proximal femur.

芳香化酶抑制剂治疗乳腺癌与加速骨丢失和骨折风险增加有关。双膦酸盐 (BPs) 是芳香化酶抑制剂相关性骨丢失 (AIBL) 的主要治疗方法，可能会改善容易骨折的关键部位的股骨。为了验证这一假设，我们基于定量计算机断层扫描 (QCT) 对接受芳香化酶抑制剂的绝经后早期乳腺癌女性进行了三维皮质骨映射。分析了 2005 年至 2015 年间在 Severance 医院（韩国）进行基线和至少一次随访 QCT 的受试者的数据（BP 用户，n = 93；BP 非用户，n = 203）。排除用药持久性低的 BP 用户（覆盖天数比例：<50%）后，BP 用户和非用户为 1：在年龄、腰椎体积骨密度 (LSvBMD)、股骨颈面积骨密度 (FNaBMD) 和全髋面积骨密度 (THaBMD) 方面匹配 1 人（每组 n = 54）。在 2.1 年的中位随访期间，使用 BP 可减轻 LSvBMD（+7.2% 对 -3.8%，p < 0.001）、FNaBMD（+1.3% 对 -2.7%，p < 0.001）和 THaBMD 的骨丢失（-0.3% 对 -2.5%，p = 0.024）。BP 对股骨皮质参数有保护作用：估计皮质厚度 (CTh) (+3.3% vs. + 0.1%, p = 0.007) 和皮质质量表面密度 (CMSD, 每单位表面积的皮质质量乘以计算皮质 BMD 与 CTh）（+3.4% 对 -0.3%，p < 0.001）。股骨颈上部和大转子等关键部位的 CMSD 增加高达 15%。BP 可防止股骨颈平均 CTh 变薄（-1.4% 对 -6.1%，p < 0.001），特别是在股骨颈前上象限（绝对差异：+12.8% 点与非使用者）。与 BP 非用户相比，BP 用户的横截面惯性矩有所改善（+4.4% vs. -0.7%，p = 0.001），屈曲率增加较少（+1.3% vs. +7.5%，p < 0.001 ）。总之，BP 的使用防止了在 AIBL 中观察到的股骨近端关键位置的皮质骨缺损。