Efficacy of two intensive decontamination protocols and their effects after 30 days on environmental contamination by cyclophosphamide

Abstract Objectives To evaluate the efficacy of two decontamination protocols on cyclophosphamide surface contamination and to explore its lasting effect 30 days later. Methods All sampling sites that were systematically contaminated with cyclophosphamide in 2017–2020 were included, from a convenience sample of centers. The first decontamination protocol consisted of four steps, each with 20 mL and a Wypall® wipe: detergent, sodium hypochlorite 2%, isopropyl alcohol 70% and water. The second decontamination protocol consisted of eight steps, each with 15 mL and a Micronsolo® microfibre wipe: detergent, sodium hypochlorite 2%, isopropyl alcohol 70%, water and then a second round with each of the four products. A first sampling was done at the end of a regular working day (T0), a second immediately following decontamination (T1) and a third 30 days later (T2) after regular operations. Cyclophosphamide was quantified by ultra-performance liquid chromatography – tandem mass spectrometry (limit of detection 0.001 ng/cm2). Results Seventeen sampling sites were included: six biological safety cabinet (BSC) front grilles, eight floors in front of BSCs and three cyclophosphamide storage shelves. The second protocol was more effective; however they both failed to completely remove all cyclophosphamide traces. BSCs and floors were found to be contaminated again 30 days later, at similar concentrations than at T0. A lasting effect was observed on the cyclophosphamide storage shelves that were less prone to be contaminated again. Conclusions Periodic decontamination with many cleaning steps is necessary on all surfaces, including those less frequently contaminated. Regular surface monitoring identifies systematically contaminated areas.