Divergence from osteoporosis screening guidelines in older breast cancer patients treated with anti-estrogen therapy: A population-based cohort study.

PURPOSE: Older Breast Cancer (BC) survivors are an increased risk of osteoporosis due to natural aging and long-term cancer treatment-related toxicity. It is well known that anti-estrogen therapy (AET), especially aromatase inhibitors (AI), is associated with rapid bone loss and thus increases the risk of osteoporosis. This study characterizes patterns and predictors of receiving guideline-recommended bone densitometry (BD) screening at AET initiation.

METHODS: A retrospective cohort study (1998-2012) of all women ≥65 years of age initiating AET was designed using claims data from Quebec's universal health care. Associations with BD screening were estimated using a generalized estimating equations regression model, adjusting for clustering of patients within physicians.

RESULTS: Among 16,480 women initiating AET, 36.1% received a baseline BD. Among AI users, the rate was 58.4%. In the multivariate analysis, age, lower socioeconomic status, tamoxifen use, lack of periodic health exam and having a general practitioner as the AET prescriber were associated with lower odds of BD screening. In terms of quality of care-related variables, lack of guideline-appropriate radiotherapy (OR: 0.69 (95% CI, 0.57-0.83), or chemotherapy consideration (0.82 (95% CI, 0.71-0.94)) and non-adherence to AET (0.76 (95% CI, 0.68-0.84)) were associated with lower odds of receiving BD screening. Women diagnosed with BC after 2003 had significantly better odds of being screened.

CONCLUSION: Despite an increase in rates since 2003, BD screening remains suboptimal, especially for women at higher risk of osteoporosis. Coordination of health care and service-delivery monitoring can potentially optimize long-term management of treatment-related toxicity in older BC survivors.