Use of bisphosphonates in breast cancer metastatic to bone: Compliance with practice guidelines

Purpose We studied the effect of the dissemination of evidence-based guidelines on the prescription of bisphosphonates to women with breast cancer metastatic to bone. Methods To determine the number of patients eligible for bisphosphonate therapy as outlined by the Cancer Care Ontario Practice Guidelines Initiative, we conducted a single-institution audit of 1,682 consecutive ambulatory patients seen by five medical oncologists who specialise in breast cancer. We reviewed patients with bone metastases seen in clinic before and after the practice guideline was distributed. The percentage of eligible patients receiving bisphosphonates was determined for each oncologist. Results Of 81 eligible patients, 30 (37.0%; range: 16.7%-50.0%) received bisphosphonates before the guideline was distributed as compared with 17 of 44 eligible patients (38.6%; range: 0%-75.0%) after the guideline was distributed. A significant improvement was seen in the number of patients receiving bisphosphonates within 2 months of diagnosis of skeletal metastases: in the preguideline period, 6 of 81 eligible patients (7.4%) received bisphosphonates within 2 months, as compared with 15 of 44 eligible patients (34.1%, p = 0.001) in the post-guideline period. Conclusions Our study suggests that clinical practice guidelines led to the earlier and more appropriate use of bisphosphonates, although a causal relationship is not proven. However, despite published literature and clinical practice guidelines to support their use, bisphosphonates were used in fewer than 40% of eligible patients at our centre. The wide range of use of bisphosphonates indicates that individual oncologists interpret and apply the evidence very differently. Ongoing evaluation, such as that reported in this paper, is required to ensure that guidelines are incorporated into practice.