506 Poster - Effect of the COVID-19 pandemic on use of bone-modifying agents for metastatic breast cancer in a UK Oncology centre

Abstract

Background: Bone-modifying agents (BMAs) prevent skeletal-related events (SREs) in breast cancer patients with bone metastases. Our centre uses mainly zoledronic acid (ZA). Denosumab is permitted, due to its high cost, only with a documented indication such as renal failure. ASCO/CCO guidelines have responded to Phase 3 trial evidence showing non-inferiority of 12-weekly ZA compared to 3 or 4-weekly, which may reduce adverse events (AEs) and cost. We report on patterns of prescription in our centre and how it has changed due to COVID-19. Materials and methods: Data was retrospectively collected on patients who received BMAs in two separate three-month periods (Oct-Dec 2019 and Apr-Jun 2020, total n = 389) including choice of BMA, frequency of administration, concurrent systemic therapy, and incidence of SREs and AEs. We searched the electronic prescribing record, outpatient letters, radiotherapy record and blood tests for each patient. Results: Of the patients receiving BMAs in period one, 88% were on ZA and 13% on denosumab. Of those on denosumab, the majority (79%) had a documented indication, of which the most common (68%) was poor renal function. Mean total duration of BMA therapy was 22 months, during which 26% received radiotherapy to the bone. We found 3 cases of osteonecrosis of the jaw (ONJ), no osteonecrosis of the auditory canal (ANAC), and no atypical femoral fractures (AFF) out of the patients still receiving BMAs in period one. 32% experienced hypocalcaemia, defined as any reading below the laboratory reference range since starting BMA therapy. In period two, 11% fewer patients received BMAs. There was a large variation in intervals prescribed within period one (Table 1) and a marked shift thereafter. The percentage of patients on 12-weekly treatment rose from 45% to 66%. The change resulted in a saving of approximately £1300 in medication cost and 60 hours of nursing time. If all patients were on 12-weekly dosing, this could save approximately a further £2400 and 120 nursing hours per year. Hypocalcaemia occurred in 8.5% of patients during period one and 7.0% during period two.Tabled 1Period one N = 205Period two N = 183ZA88%84%Denosumab13%16%4-weekly24%6%6-weekly13%10%8-weekly17%18%12-weekly45%66%Other frequency2%0%Concurrent chemotherapy30%34% Open table in a new tab Conclusions: Despite strong evidence supporting use of 12 weekly ZA, local practice was slow to change. During COVID-19 it became necessary to minimise exposure of patients to hospital. This resulted in a rapid shift in practice; leading to reduced treatment burden, less hypocalcaemia, liberation of nursing time and cost saving in the COVID-19 period and beyond. No conflict of interest.