Spatial and Temporal Variability in Antineoplastic Drug Surface Contamination in Cancer Care Centers in Alberta and Minnesota.

The health risks of exposure to antineoplastic drugs (ADs) are well established, and healthcare professionals can be exposed while caring for cancer patients receiving AD therapy. Studies conducted worldwide over the past two decades indicate continuing widespread surface contamination by ADs. No occupational exposure limits have been established for ADs, but concerns over exposures have led to the development of guidelines, such as United States Pharmacopeia (USP) General Chapter <800> Hazardous Drugs-Handling in Healthcare. While recommending regular surveillance for surface contamination by ADs these guidelines do not provide guidance on sampling strategies. Better characterization of spatial and temporal variability of multidrug contamination would help to inform such strategies. We conducted surface-wipe monitoring of nine cancer care centers in Alberta, Canada and Minnesota, USA, with each center sampled eight times over a 12-month period. Twenty surfaces from within pharmacy and drug administration areas were sampled, and 11 drugs were analyzed from each wipe sample. Exposure data were highly left-censored which restricted data analysis; we examined prevalence of samples above limit of detection (LOD), and used the 90th percentile of the exposure distribution as a measure of level of contamination. We collected 1984 wipe samples over a total of 75 sampling days resulting in 21 824 observations. Forty-five percent of wipe samples detected at least one drug above the LOD, but only three of the drugs had more than 10% of observations above the LOD: gemcitabine (GEM) (24%), cyclophosphamide (CP) (16%), and paclitaxel (13%). Of 741 wipe samples with at least one drug above LOD, 60% had a single drug above LOD, 19% had two drugs, and 21% had three drugs or more; the maximum number of drugs found above LOD on one wipe was 8. Surfaces in the compounding area of the pharmacy and in the patient area showed the highest prevalence of samples above the LOD, including the compounding work surface, drug fridge handle, clean room cart, passthrough tray, and hazardous drug room temperature storage, the IV pump keypad, patient washroom toilet handle, patient washroom door handle, nurses' storage shelf/tray, and patient side table. Over the course of the study, both 90th percentiles and prevalence above LOD varied without clear temporal patterns, although some centers appeared to show decreasing levels with time. Within centers, the degree of variability was high, with some centers showing changes of two to three orders of magnitude in the 90th percentile of drug concentrations month to month. A clear difference was observed between the six centers located in Alberta and the three in Minnesota, with Minnesota centers having substantially higher percentages of samples above the LOD for CP and GEM. Other factors that were associated with significant variability in exposures were drug compounding volume, size of center, number of patients seen, and age of the center. We hope that demonstrating variability associated with drug, surface, clinic-factors, and time will aid in a better understanding of the nature of AD contamination, and inform improved sampling strategies.

Assessing variability of antineoplastic drugs handling practices in clinical settings.

The United States Pharmacopeia (USP) Chapter <800> guidelines will be adopted in the U.S. and Canada in 2019, requiring regular surface sampling for antineoplastic drug (AD) surface contamination as a means of environmental surveillance. USP Chapter <800> does not provide guidance on when and where to sample. Research to support the development of such guidance within a broader sampling strategy is limited. This study was conducted to help address some of the underlying information gaps by identifying surfaces pharmacy and nursing staff are likely to contact, presenting a potential dermal exposure risk. Observations were conducted at one regional and one urban clinic, providing insight into inter- and intra-worker variability and between-clinic differences based on size and patient load. Thirteen surfaces in the compounding pharmacies and 14 surfaces in the patient administration were initially selected for video observations. Following a preliminary assessment to eliminate surfaces that were touched infrequently or not at all, five commonly touched surfaces in the compounding pharmacy areas (vials, syringes, IV lines, IV bags, waste bags) and six commonly touched surfaces in the patient administration area (yellow containment bag, IV bag, IV line, patient port, computer workstation) were assessed further. Variability between healthcare staff and clinics in pharmacy staff was low for both the mean frequency and duration of touch to surfaces. Differences between clinics in frequency of contact among nursing staff in patient administration areas were significant (two-way ANOVA) for five of the six surfaces. Duration of contact was not significantly different except for duration of touching the IV pump. These insights will be used to give guidance in selecting locations for a longitudinal surveillance study and help tailor worker training to reduce exposure risks.