Screening and treatment of osteoporosis in breast cancer survivors treated with aromatase inhibitors: Gap between the national guidelines and real-world practice.

Abstract

113 Background: Breast cancer survivors who are on adjuvant therapy with Aromatase Inhibitors (AIs) are known to have an increased risk of osteoporosis. AIs reduce estrogen levels and cause accelerated loss of bone density. Being at high risk for osteoporosis, these patients should be screened and followed up for bone mineral density (BMD) with dual energy X-ray absorptiometry (DEXA) scan as directed by national guidelines. The purpose of this study was to evaluate if this patient population is adequately screened and intervened appropriately. Methods: We conducted a two center, retrospective, clinical observational study at Guthrie cancer center at Sayre and Corning using Guthrie tumor registry. Patients with diagnosis of invasive breast cancer and on adjuvant therapy with AIs were included in this study. Patients with metastatic bone disease and those who were receiving palliative care were excluded. Results: During the study period, a total of 703 breast cancer patients were identified and 292 patients were on AIs. Baseline DXA scan for BMD was done in 54 % (158 out of 292) patients. Of these, 22% (n=35) had osteoporosis and 43% (n=68) had osteopenia. FRAX (Fracture risk assessment tool) score using WHO algorithm was calculated in patients with osteopenia. After calculating FRAX score, 28 of 68 patients were found to have ≥3% ten year probability (TYP) of a hip fracture or ≥20% TYP of a major osteoporosis-related fracture. These 28 patients with osteopenia and 35 patients (total n=64) with osteoporosis were required to be on treatment as per guideline recommendations. Only 23% (15 of 64) patients recieved treatment. Two year follow up on patients taking AI was done (n=292) and 46% (n= 137) patients had repeat BMD. Of the patients who had known osteoporosis and TYP of hip fracture ≥ 3% or a TYP of a major osteoporosis-related fracture ≥ 20%, only 54% (35 of 64) had follow up BMD. Conclusions: This study highlights the fact that osteoporosis is an under-detected and inadequately treated condition in breast cancer survivors who are on AIs. There is still a huge gap between guidelines and real world practice on prevention and treatment of osteoporosis this patient population.