Bone density changes during adjuvant aromatase inhibitor treatment in breast cancer patients: Single center experience

Abstract

e11565 Background: Adjuvant aromatase inhibitors (AI) therapy in breast cancer accelerates bone loss resulting in increased incidence of fracture. We evaluated the effect of AI on bone density changes among breast cancer patients. Method: A total of 85 patients who had adjuvant AI for more than 24 months and 3 Dual energy X-ray Absorptiometry (DXA) scans were included in this study. Annual bone density change was calculated and correlated with various risk and prognostic factors. Results: Adjuvant AI was given in up-front (50), sequential (15) and extended adjuvant (17) therapy settings, with a median duration of 31 months. Intervals between scans varied from 6 - 33 months (median = 13 months), 63 patients had baseline DXA scans undertaken within 6 months from start of AI. Bisphosphonate was prescribed to 35 patients during AI therapy according to local practice. Changes in bone density according to WHO classification is shown in the table. Annual bone density change in the spine at 2nd scan was (-9.2% to +11%, mean = -0.89±4.11), after 3rd scan, (-11.7% to +10.7%, mean = 0.021±3.84). In the group of patients who had adjuvant chemotherapy (59 patients), significant bone loss was seen in the patients who did not have bisphosphonate (n=39), (-0.011 in BMD, Mean=0.88±0.02) compared to those who had bisphosphonate (n=20), (0.036 in BMD, Mean=0.93±0.02). In the patients who did not have chemotherapy (n=26), no bone loss was seen whether bisphosphonate was used or not. No clinical bone fracture was reported among patients who had osteoporosis at baseline. Conclusions: The patients who had chemotherapy are more likely to lose bone density and close monitoring is required for bisphosphonate therapy. Bone loss is more significant in the lumbar spine compared to the hip. Following intervention with bisphosphonate, the rate of bone loss was reduced, and as a result only 2.3% of patients developed osteoporosis during AI treatment. AI can be safely given from the bone health point of view with the appropriate use of bisphosphonate. [Table: see text] No significant financial relationships to disclose.