UBC Theses and Dissertations
Bone health and osteoporosis in women diagnosed with breast cancer in British Columbia Tseng, Ling-I Olivia
Background: Women diagnosed with breast cancer are at higher risk of osteoporosis and osteoporotic fractures. Information is lacking on utilization of bone mineral density testing in British Columbia, and fracture risks associated with tamoxifen and aromatase inhibitors to plan care. Methods: Three studies were conducted on women diagnosed with breast cancer. Study 1, a retrospective cross-sectional study evaluated the utilization of bone mineral density testing in 1995-2008 and identified factors associated with different testing rates using secondary data-linkage in older women aged ≥65 and diagnosed with breast cancer for ≥3 years in British Columbia, Canada. Study 2, a pilot randomized controlled trial, assessed the feasibility of a protocol designed to improve bone health management, especially bone mineral density testing rates, with educational material in older women aged ≥65 and diagnosed with breast cancer for ≥3 years. And study 3, a systematic review with meta-analysis, estimated fracture risks associated with tamoxifen and aromatase inhibitors in younger women aged ≤65. Results: In older women aged ≥65, proportions of women with ≥1 bone mineral density test per calendar year increased from 1.0% in 1995 to 10.1% in 2008. Women with lower socio-economic status or rural residence were significantly less likely to have a bone mineral density test. The study protocol is feasible with a promising effect of educational material on bone mineral density testing rates (17%, 95%CI=6 to 33) in the 54 participants during the pilot study six-month follow-up period. In younger women aged ≤65, fracture risk did not differ between the tamoxifen and no-tamoxifen groups. Aromatase inhibitor-associated fracture risk was 17% and 35% higher than the risks in the no-aromatase inhibitor group and tamoxifen group respectively. The higher aromatase inhibitor-associated fracture risk compared with tamoxifen descreased slowly over time. The risk was significantly higher during the treatment period, but not the post-treatment period. Conclusions: Increased risk of fractures is reported in women diagnosed with breast cancer and treated with aromatase inhibitors, while screening for osteoporosis with bone mineral density testing is sub-optimal. There is a need to improve bone health management programs which should include educational materials.
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