Background Compounding units assigned a restrictive shelf-life for anticancer admixtures results in economic loss due to wastage of partially used vials. Novel approaches in the preparation of doses are continually sought which ensure maximal drug utilisation without compromising patient safety.

Purpose To perform cost analyses of captured and retrospective cytotoxic waste data and delineate the risks and benefits associated with shelf-life extension.

Material and methods For the observational model, fieldwork was conducted over 2 months in a cross sectional study at two public hospitals which have cytotoxic units, covering haematology and oncology care. Data were recorded by means of a validated data collection sheet. Retrospectively, 22 796 doses were evaluated from logbook databases for the same year. Three distinct preparation scenarios, comprising individualised, same day grouping and weekly grouping of doses, were constructed for the agent established as the top contributor to the overall wastage sum. The economic impact for each scenario was computed. Volumetric and dosage values were translated to costs for all phases. Quality assurance pharmacists and literature were consulted to assess the feasibility of extending stability time frames.

Results Retrospectively, 36 prescribed agents, including cytotoxic (n=34) and biological (n=2) therapies, satisfied the inclusion criteria. Logged wastage for both institutions amounted to €10 380, with an annual extrapolation of €220 000. Retrospective waste costs (€301 138) exceeded the projected figure by 36.8%. This sum represents approximately 7.2% of the annual expenditure on anticancer parenterals (€4.2M). Bortezomib (43%, €77 314) at the haematology section and trastuzumab (58%, €70 176) at the oncology unit were the predominant accountable agents. Over 70% of the total waste expense was attributed to six agents, namely bortezomib, trastuzumab, fludarabine, pegasparaginase, pemetrexed and rituximab. For bortezomib doses, the advanced weekly preparation yielded annual savings of more than €40 000 compared with the current same day grouping sessions. Advanced preparation offers the additional advantages of streamlined workflow, diminished cytotoxic errors and reduced treatment delays. Reported barriers were mostly related to concerns on stability and sterility.

Conclusion The percentage waste cost from global budget surpassed those determined by other studies. Shelf-life extension facilitates grouping of antineoplastic doses, leading to significant recovery of waste. Measures must regard economic considerations in light of logistical and patient factors.

No conflict of interest