Cross-Sectional Evaluation of Surface Contamination with Antineoplastic Drugs in Canadian Health Care Centres.

Background: Surfaces in health care centres are often contaminated with traces of antineoplastic drugs. Such contamination should be limited as much as possible, to reduce workers' exposure.

Objectives: The primary objective was to monitor environmental contamination with 9 antineoplastic drugs in oncology pharmacy and patient care areas of Canadian health care centres. The secondary objective was to explore the use of sodium hypochlorite as a cleaning agent for cyclophosphamide contamination.

Methods: This cross-sectional evaluation was conducted from January to April 2018. Twelve standardized sites were sampled at each participating centre: 6 in the oncology pharmacy and 6 in patient care areas. Six of the antineoplastic drugs (cyclophosphamide, ifosfamide, methotrexate, gemcitabine, 5-fluorouracil, and irinotecan) were quantified by ultra-performance liquid chromatography - tandem mass spectrometry. For the other 3 antineoplastic drugs (docetaxel, paclitaxel, and vinorelbine), samples were screened for contamination but not quantified. The effect of using sodium hypochlorite as a cleaning agent was evaluated with a Kolmogorov-Smirnov test for independent samples.

Results: Of 202 Canadian centres invited, 79 participated. A total of 887 surface samples were analyzed, 467 from pharmacy areas and 420 from patient care areas. Cyclophosphamide was the drug most often found as a contaminant (32.2% [286/887] of samples positive, 75th percentile of measured contamination 0.0017 ng/cm, 90th percentile 0.021 ng/cm). The front grille inside the hood (80.8% [63/78] of samples positive for at least one antineoplastic drug), treatment chair armrest (78.9% [60/76]), storage shelf in pharmacy (61.5% [48/78]), and floor in front of the hood (60.3% [47/78]) were the most frequently contaminated surfaces. Cleaning with a sodium hypochlorite solution was highly variable. Among centres that reported using sodium hypochlorite to clean armrests on patient chairs, the concentration of cyclophosphamide was lower (0.00866 versus 0.0300 ng/cm, = 0.014).

Conclusions: Despite growing awareness and implementation of new safe-handling guidelines, surfaces in health care centres were contaminated with traces of many antineoplastic drugs. Providing centres with attainable goals (e.g., 75th to 90th percentile relative to other similar centres) would help in identifying the sampling sites where improvements are needed and in achieving lower surface contamination.