BackgroundMost previous studies of the incidence and economic impact of drug-related hospital admissions were not cancer specific, despite the fact that drug-related problems (DRPs) are of particular concern in oncology. ObjectiveThe goals of this study were to assess the economic impact, particularly the length of stay (LOS) and direct medical costs (DMC), of drug-related hospital admissions and the associated factors in cancer patients in Singapore. MethodsA prospective study was conducted over a 5-month period in 2 oncology wards at the largest acute tertiary hospital in Singapore. Drug-related admissions were identified from all oncology admissions to these wards, and the demographic, clinical, and cost data of these drug-related admissions were collected. The association between LOS and DMC as well as their associations with age, severity, and preventability of DRPs were examined. A nationwide estimation was made to determine the overall DMC of drug-related hospital admissions among cancer patients. ResultsA total of 151 drug-related admissions that occurred among 137 cancer patients were identified. The mean DMC (in Singapore dollars [SGD]) and LOS per drug-related admission were SGD $4747 and 6.1 days, respectively. A nationwide extrapolation estimated an annual total DMC of SGD $16.2 million. Longer LOS was found to be correlated with higher DMC (rs = 0.86, P < 0.001) and preventable DRPs (P = 0.02). ConclusionsDrug-related hospitalization among cancer patients is costly; therefore, more attention is warranted to develop and improve strategies for preventing drug-related morbidity and mortality in cancer patients.