Protective Effect Of Zoledronic Acid On Bone Loss Associated With Endocrine Therapy In Breast Cancer

Objective:To evaluate the efficacy and safety of zoledronic acid in the prevention and treatment of bone loss associated with endocrine therapy in breast cancer.Methods:Patients with postmenopausal breast cancer(natural menopause / ovariectomy /ovarian function suppression)who received endocrine therapy were collected from Department of Breast Surgery,the First Hospital of Jilin University from June 2018 to September 2020.There were 70 patients who received zoledronic acid injection as soon as postmenopausal endocrine therapy began and 38 patients who received zoledronic acid injection after more than half a year of postmenopausal endocrine therapy.Zoledronic acid was given intravenously every 6 months for both group enrolled.The baseline and 12 th month bone mineral density(BMD)were measured by dual energy X-ray absorptiometry(DEXA).Symptoms of bone pain during the endocrine therapy were recorded.By comparing the changes of BMD and the degree of bone pain before and after treatment,the effect of zoledronic acid on bone loss associated with postmenopausal endocrine therapy was evaluated,and the optimal time of administration and applicable population were explored.Results:(1)There was no statistically significant difference in age,BMI,endocrine therapy and chemotherapy between early group and delayed group.(2)The baseline BMD of lumbar spine in the delayed group was lower than that in the early group,and the difference was statistically significant(p < 0.05).The baseline BMD of the total hip was lower than that in the early group,and the difference was not statistically significant.(3)At the 12 th month after treatment,the BMD of lumbar spine increased significantly(p < 0.05),and the baseline BMD-values of total hip were maintained.(4)According to menopausal status,the BMD of lumbar spine in established postmenopausal patients increased significantly after zoledronic acid treatment(p<0.05).The BMD of lumbar spine also increased in recently menopausal patients,but there was no statistically significant difference.(5)According to the risk classification of osteoporosis,the BMD of lumbar spine increased significantly after zoledronic acid treatment in middle-high risk patients(p < 0.05),and the BMD of total hip could be maintained at a baseline level.Low-risk patients also benefited from the use of zoledronic acid.(6)NRS score decreased significantly at the 12 th month after treatment(p <0.05),compared with the NRS score when bone pain occurred for the first time.Conclusion:(1)Zoledronic acid can prevent and improve bone loss in breast cancer patients treated with AI or OFS.(2)Established postmenopausal patients and patients at medium and high risk of osteoporosis can benefit more from the use of zoledronic acid.(3)Compared with delayed medication,immediate zoledronic acid administration can significantly reduce bone pain associated with postmenopausal endocrine therapy.