Environmental Contamination with Cyclophosphamide, Ifosfamide, and Methotrexate: A Study of 51 Canadian Centres

Occupational exposure to hazardous drugs may lead to adverse reproductive effects. There is no safe exposure limit for health care professionals.

To monitor levels of cyclophosphamide, ifosfamide, and methotrexate contamination in oncology pharmacy and patient care areas in Canadian health care institutions.

The study was conducted in 2014. Hospitals with at least 50 acute care beds were invited to participate. At each participating centre, 12 standardized sites (6 in pharmacy areas and 6 in patient care areas) were sampled. The samples were analyzed for the presence of cyclophosphamide, ifosfamide, and methotrexate by ultra-performance liquid chromatography tandem mass spectrometry technology. The limits of detection were 0.36 pg/cm(2) for cyclophosphamide, 0.95 pg/cm(2) for ifosfamide, and 0.97 pg/cm(2) for methotrexate. Descriptive statistical analyses were performed to determine the median, 75th percentile, and maximum levels.

Fifty-one hospitals participated in this descriptive study, and a total of 584 samples were quantified. Overall, 294 (50%) of the samples were positive for cyclophosphamide, 125 (21%) for ifosfamide, and 54 (9%) for methotrexate. The most frequently contaminated sampling sites in pharmacy areas were the front grille inside the hood and the floor in front of the hood and, in patient care areas, the armrest and outpatient clinic counter. The 75th percentiles for surface concentration were 10.8 pg/cm(2) for cyclophosphamide, 1.59 pg/cm(2) for ifosfamide, and below the limit of detection for methotrexate.

Relative to 3 other multicentre studies conducted in Quebec over the past few years, the proportion of positive samples remained constant. Nonetheless, the 75th percentile surface concentration of antineoplastic drugs has been decreasing and seems to have reached a plateau. Local (country-specific or region-specific) and attainable goals for surface contamination with hazardous drugs should be set annually, so long as no health-based limit is known.