Variability in anthracycline dose conversions and cardiotoxicity monitoring: insights from hospital pharmacists on institutional protocols in oncology practice

Abstract Purpose Anthracycline-induced cardiotoxicity is dose-dependent, yet guidelines provide inconsistent cumulative dose thresholds and few standards for converting doses when multiple agents are used. Moreover, no formal guideline exists to unify these practices and responsibilities. Therefore, we evaluated anthracycline dosing and cardiotoxicity monitoring across Dutch hospitals to identify variability. Methods A national cross-sectional survey was conducted among hospital pharmacists in the first quarter of 2024 in the Netherlands. Hospitals completed a 16‑item questionnaire assessing cumulative dose thresholds, equivalence factors for converting to doxorubicin‑equivalent doses, cardiac monitoring protocols and circumstances under which thresholds are exceeded. Results Responses were received from 43 of 69 hospitals (62%). Reported cumulative dose thresholds varied widely for idarubicin (150—450 mg/m 2 ) and mitoxantrone (80—250 mg/m 2 ); equivalence factors differed more than ten‑fold between institutions. Nearly half of respondents reported exceeding recommended cumulative dose thresholds in specific clinical contexts. Cardiac monitoring was inconsistent, with 65% of hospitals not routinely measuring left ventricular ejection fraction. Moreover, multigated acquisition scans were used more often than echocardiography despite guideline preference for the latter. Conclusion Our results reveal substantial heterogeneity in anthracycline dosing and cardiotoxicity monitoring across hospitals. Variability in equivalence factors, particularly for mitoxantrone and idarubicin, may lead to misestimation of cumulative cardiotoxic risk. These findings support the need for standardized approaches to dose conversion and improved adherence to cardiac monitoring recommendations to enhance patient safety.