The Interaction of Lean Body Mass With Fat Body Mass Is Associated With Vertebral Fracture Prevalence in Women With Early Breast Cancer Undergoing Aromatase Inhibitor Therapy

Aromatase inhibitors (AIs) induce depletion of estrogen levels, causing bone loss and increased fracture risk in women with breast cancer. High‐fat body mass (FBM) emerged as an independent factor associated with the prevalence of morphometric vertebral fractures (VFs) in patients undergoing AIs. We explored the role of lean body mass (LBM) and the interaction of LBM with FBM in predicting the occurrence of VFs in postmenopausal women who were either AI‐naïve or AI‐treated. A total of 684 consecutive breast cancer patients were enrolled in this cross‐sectional study. Each woman underwent a dual‐energy X‐ray absorptiometry (DXA) scan, measuring bone mineral density (BMD), LBM, and FBM; VFs were assessed using a quantitative morphometric analysis of DXA images. After propensity score matching, the study population was restricted to 480 women, 240 AI‐naïve and 240 AI‐treated. We used multivariable logistic regression models to explore the associations between baseline characteristics, VF prevalence and the interaction between LBM, FBM and AI therapy. No interaction between LBM and AI therapy on VF prevalence was shown. Conversely, we reported a significant interaction between LBM, FBM and AI therapy (p = .0311). Among AI‐treated women having LBM below and FBM above or equal the median value, VF prevalence was numerically higher (15/31; 48.4%) than in other subgroups (VF prevalence: 35.7% in high‐LBM and low‐FBM group, 23.2% in high‐LBM and high‐FBM group, and 19.8% in low‐LBM and low‐FBM group). Among AI‐naïve women, the greatest VF proportion was observed in the subgroup with LBM and FBM below median value (25/92; 27.2%). This study suggests a synergism between LBM and FBM in predicting the morphometric VF in women with early breast cancer undergoing AIs. This observation is new and deserves further investigation. The assessment of body composition by DXA might be useful when estimating fracture risk in this population. © 2020 American Society for Bone and Mineral Research © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Increased Fracture Risk in Women Treated With Aromatase Inhibitors Versus Tamoxifen: Beneficial Effect of Bisphosphonates

Aromatase inhibitors have been associated with accelerated bone loss and an increased risk of osteoporotic fractures. Currently, bisphosphonates are recommended to reduce fracture risk in these patients. The aim of this study is to evaluate the fracture risk in breast cancer patients receiving aromatase inhibitors, compared to tamoxifen users, and to assess the effectiveness of oral bisphosphonates in reducing fracture risk. We performed an observational cohort study up to 10 years of follow-up. Data were extracted from primary care records in a population database. Women diagnosed with breast cancer between 2006 and 2015 and treated with tamoxifen or aromatase inhibitors (n = 36,472) were stratified according to low (without osteoporosis diagnosis nor bisphosphonates exposure) or high (with osteoporosis and/or treated with bisphosphonates) fracture risk. Cox models were used to calculate hazard ratios (HR [95% CI]) of fracture from the propensity score-matched patients. Sensitivity analyses account for competing risk of death were performed (subdistribution hazard ratio [SHR] [95% CI]). In postmenopausal women, fracture risk in aromatase inhibitor users showed an HR 1.40 [95% CI,1.05 to 1.87] and SHR 1.48 [95% CI, 1.11 to 1.98], compared to tamoxifen. Observing aromatase inhibitors patients at high risk of fracture, bisphosphonate-treated patients had an HR 0.73 [95% CI, 0.51 to 1.04] and SHR 0.69 [95% CI, 0.48 to 0.98] compared to nontreated. In conclusion, fracture risk in postmenopausal women during aromatase inhibitor treatment, in real-life conditions, was >40% compared to tamoxifen, corroborating previous randomized controlled trials results. In high-risk patients, bisphosphonate users had lower significant fracture incidence during aromatase inhibitor therapy than nonbisphosphonate users. Monitoring fracture risk and related risk factors in aromatase inhibitor patients is advisable. © 2019 American Society for Bone and Mineral Research.

Performance of FRAX in Women with Breast Cancer Initiating Aromatase Inhibitor Therapy: A Registry-Based Cohort Study

FRAX was developed to predict 10-year probability of major osteoporotic fracture (MOF) and hip fracture in the general population. Aromatase inhibitors (AI) used in breast cancer induce loss in bone mineral density (BMD) and are reported to increase fracture risk. AI exposure is not a direct input to FRAX but is captured under "secondary osteoporosis". To inform use of FRAX in women treated with AI, we used a population-based registry for the Province of Manitoba, Canada, to identify women aged ≥40 years initiating AI for breast cancer with at least 12 months' AI exposure (n = 1775), women with breast cancer not receiving AI (n = 1016), and women from the general population (n = 34,205). Among AI users, fracture probability estimated without BMD (AI use coded as secondary osteoporosis) significantly overestimated risk (10-year observed/predicted ratio 0.56, 95% confidence interval [CI] 0.45-0.68; 10-year hip fracture observed/predicted ratio 0.33, 95% CI 0.18-0.49). However, when BMD was included in the fracture probability, there was no significant difference between observed and predicted fracture risk. In Cox proportional hazards models, FRAX stratified risk of MOF, hip, and any fracture equally well in all subgroups (p-interaction >0.1). When adjusted for FRAX score without BMD, with AI use coded as secondary osteoporosis, AI users were at significantly lower risk for MOF (hazard ratio [HR] = 0.78, 95% CI 0.64-0.95), hip fracture (HR = 0.46, 95% CI 0.29-0.73) and any fracture (HR = 0.75, 95% CI 0.63-0.89). AI use was no longer significantly associated with fractures when AI use was not entered as secondary osteoporosis in FRAX without BMD or when BMD was included in the FRAX calculation. In conclusion, FRAX scores stratify fracture risk equally well in women receiving AI therapy as in non-users, but including secondary osteoporosis as a risk factor for AI users overestimates fracture risk. Our results call this practice into question. © 2019 American Society for Bone and Mineral Research.

Drug-induced osteoporosis: from Fuller Albright to aromatase inhibitors

Many commonly prescribed medications, such as selective serotonin reuptake inhibitors, proton pump inhibitors, thiazolidinediones, aromatase inhibitors, and androgen deprivation therapy, have been associated with adverse skeletal effects. The levels of evidence in support of a causal relationship between drug use and the development of bone loss and fractures are variable. For some drugs, a causal relationship is suspected (but not proven) based on observational studies, while in others causality is firmly established with randomized, controlled clinical trials. The mechanism of action for skeletal damage is poorly understood for some drugs and well known for others. Guidelines for managing bone health in patients taking some medications with potential skeletal toxicity have been developed using the best available evidence and expert opinion. This is a review of selected medications that have been associated with bone loss and fractures, with recommendations for clinical care.

Vaginal estriol-lactobacilli combination and quality of life in endocrine-treated breast cancer

OBJECTIVE

We investigated the effect of a combination of vaginal ultra-low-dose estriol with lactobacilli on the sexual functioning domain of quality of life during the treatment of breast cancer survivors on an aromatase inhibitor with vaginal atrophy.

SUBJECTS AND METHODS

This was an open-label, bicentric, exploratory, clinical study in 16 postmenopausal breast cancer survivors on aromatase inhibitors suffering from vaginal atrophy-induced sexual disorders. Atrophy symptoms were assessed by scoring with an 11-point estimation scale (0 = not at all, 10 = worst imaginable feeling). Sexuality parameters of quality of life and medication adherence were recorded in a patient's diary and in the Female Somatic Sexual Experience Instrument (FSSEI) questionnaire. Patients underwent an initial treatment for 4 weeks (one vaginal tablet of Gynoflor(®) containing 0.03 mg estriol daily), followed by maintenance therapy (three vaginal Gynoflor(®) tablets weekly) for 8 weeks.

RESULTS

Vaginal dryness continuously improved from a median score of 8 at entry to a score of 4 at the end of initial therapy, and a median score of 2 at the end of maintenance therapy. Normal sexual activity before breast cancer diagnosis was reported by 14 women (88%). At study entry, only three women (19%) were sexually active. At the end of the Gynoflor(®) regimen, ten women (63%) reported sexual activity, of which seven (44%) reported sexual intercourse. The FSSEI demonstrated a non-significant trend of improvement of parameters related to sexuality.

CONCLUSIONS

Local vaginal therapy with Gynoflor(®) in breast cancer survivors on aromatase inhibitors reporting atrophic vaginitis could be considered as a useful treatment for the quality of sexual life.