Multicenter study of environmental contamination with cyclophosphamide, ifosfamide, and methotrexate in 66 Canadian...

Oncology workers are occupationally exposed to antineoplastic drugs. This exposure can induce adverse health effects. To reduce their exposure, contamination on surfaces should be kept as low as possible. The main objective of this study was to monitor environmental contamination with cyclophosphamide, ifosfamide, and methotrexate in oncology pharmacy and patient care areas in Canadian centers. The secondary objective was to describe the impact of some factors that may limit contamination.

This is a descriptive study. Twelve standardized sites were sampled in each participating center (six in the pharmacy and six in patient care areas). Samples were analyzed for the presence of cyclophosphamide, ifosfamide, and methotrexate by ultra-performance liquid chromatography-tandem mass spectrometry technology. Descriptive statistical analyses were done and results were compared with a Kolmogorov-Smirnov test for independent samples.

In 2016, 66 centers participated in this study (66/202, 32.7%). Overall, 43.4% (326/752) of the samples were positive for cyclophosphamide, 13.2% (99/752) for ifosfamide and 6.9% (52/752) for methotrexate. The 75th percentile value of cyclophosphamide surface concentration was 6.8 pg/cm² and lower than the limit of detection for ifosfamide and methotrexate. Centers who prepared more antineoplastic drugs per year (p < 0.0001), who used more cyclophosphamide per year (p < 0.0001) and who primed antineoplastic IV tubing in patient care unit by nurses (p = 0.004) showed significantly higher surface contamination to cyclophosphamide.

Environmental surveillance is one part of a comprehensive approach for minimizing hazardous exposures in healthcare. This study highlights a low level of contamination of three hazardous drugs amongst 66 Canadian centers. Regular environmental monitoring is a good practice to maintain contamination as low as reasonably achievable.