Background:
Zoledronic acid is beneficial in postmenopausal, primary breast cancer patients, regardless of hormone receptor and HER2 status. Due to effects on bone physiology, bisphosphonates modify the metastases process, significantly reducing rates of recurrence and mortality. The American Society of Clinical Oncology guideline recommends initiating bisphosphonates within 3 months of definitive surgery or 2 months of adjuvant chemotherapy completion.
Aim:
To assess timeliness and explore potential factors underlying delays to zoledronic acid initiation in adjuvant and neoadjuvant breast cancer patients at a large metropolitan teaching hospital.
Methods:
A retrospective audit was conducted on patients receiving zoledronic acid between 2023-2024. Data including demographic data, chemotherapy and zoledronic acid treatment dates, surgery date, and reasons delaying zoledronic acid initiation were extracted from electronic medical records. The primary endpoints were median time from chemotherapy completion or surgery to the first zoledronic acid dose, and percentage of patients initiated on zoledronic acid within guideline-recommended timeframes. The secondary endpoint was to identify reasons underlying delays to zoledronic acid initiation.
Results:
177 patients (median age 57 years) were included. Among adjuvant patients, the median time to zoledronic acid initiation was 6 months; 12.3% (10/81) commenced zoledronic acid within the recommended 2-month period. For neoadjuvant patients or patients undergoing surgery alone, the median time to zoledronic acid initiation was 6 months in both groups; 27.3% (6/22) and 18.9% (14/74) received zoledronic acid within the recommended 3-month period respectively. Common causes delaying zoledronic acid initiation included radiotherapy, initiation of hormonal therapy and consequential review, and dental clearance.
Discussion:
Delay to zoledronic acid initiation was observed across all treatment groups. Pharmacists can play a role in raising awareness of delayed zoledronic acid initiation and implement strategies to improve timely administration to ensure optimal patient outcomes.