Abstract P1-11-24: Aromatase inhibitors and bone health in women 75 and older treated for early stage breast cancer

Abstract

Abstract Introduction: Breast cancer is the most common cancer in women. In estrogen receptor positive breast cancers aromatase inhibitors (AI) are a common treatment option. AIs are associated with a reduction in bone mineral density, and patients with osteopenia at baseline have a higher risk of developing subsequent osteoporosis while on AI therapy. Women age 75 and older are a fast growing subset of breast cancer patients and commonly have osteopenia or osteoporosis at time of breast cancer diagnosis. Studies of long-term effects of AI on bone density in these older women who are at higher risk of osteoporosis and musculoskeletal events are lacking at this time. Objective: To evaluate the objective change in bone density in women over the age of 75 diagnosed with early stage breast cancer and treated with AI. Methods: A retrospective chart review of 49 patients ages 75 to 95 diagnosed with early stage breast cancer and treated with AI. Pretreatment DEXA scan results were recorded as well as prevalence of bone targeted therapy at the time of breast cancer diagnosis. Incidence of bone targeted therapy initiated subsequent to cancer diagnosis and changes in T score on follow up DEXA scans were collected as well. Incidence of musculoskeletal events and osteonecrosis of the jaw were recorded. Results: 40/49 (81.6%) of study women were found to have osteopenia (23/49 [46.9%]) or osteoporosis (17/49 [34.7%]) on pre-treatment DEXA scans. Only 16/49 (32.7%) of patients were on bone-targeted treatment prior to breast cancer diagnosis. Of the patient with baseline osteoporosis, only 4/17 (23.5%) were on bone targeted treatment prior to breast cancer diagnosis. 25/49 (51%) of women were initiated on bone targeted therapy subsequent to breast cancer diagnosis and following review of pretreatment DEXA scan results. 5/49 (10.2%) of women were started on bisphosphonates and 7/49 (14.3%) were started on Denosumab. On the first subsequent DEXA scan at a median follow up of 2 years, 14/21(66.7%) of women were noted to have stable DEXA findings (defined as change in T score less than 0.5). 7/21 (33.3%) had a worsening T score on repeat DEXA. Of those patients with worsening T score, 3/7 (42.9%) changed categories (either from normal density to osteopenia or from osteopenia to osteoporosis. 3/49 (6%) of patients sustained a fracture while on AI therapy. There were no reported events of osteonecrosis of the jaw. Subsequent DEXA showing stabilitySubsequent DEXA showing worsening T scoreFractureBaseline Normal bone density1 (n=3)2 (n=3)1 (n=9)Baseline Osteopenia9 (n=12)3 (n=12)0 (n=12)Baseline Osteoporosis4 (n=6)2 (n=6)2 (n=17) Conclusion: Many elderly women are found to have osteopenia or osteoporosis at the time of breast cancer diagnosis and AI initiation. Most elderly patients had stable findings on subsequent bone density testing. Women with known osteoporosis initiated on bone-targeted therapy and AI did not have significant worsening in bone health. With appropriate treatment and monitoring elderly women with baseline decreased bone density can be treated safely with aromatase inhibitors. Citation Format: Baer L, Chaudhry B, Kudelka A, Cohen J, Stopeck AT. Aromatase inhibitors and bone health in women 75 and older treated for early stage breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-11-24.