Evolution of chemical contamination in a Cytotoxic Reconstitution Unit

Introduction
Chemical contamination monitoring in a Cytotoxic Reconstitution Unit (CRU) is important in order to evaluate and limit cross-contamination and staff exposure to these molecules, in particular through the implementation of appropriate decontamination.

Material and Methods
We conducted chemical contamination monitoring of our CRU in 2018 and 2022 on respectively 18 and 25 points.
The samples were collected using moistened filter papers, rubbed on a surface of 225 cm².
18 molecules were researched for each point, by liquid chromatography coupled with tandem mass spectrometry. The analyses were subcontracted to the laboratory of the Léon Bérard Center.

Results
In 2018, at least one cytotoxic molecule was detected in 10 of 18 sampled points (55.6%), compared with 15 of 25 sampled points in 2022 (60%).
The most frequently detected molecules were 5-fluorouracil, cyclophosphamide, cytarabine, gemcitabine, ifosfamide and platinum derivates.
Of the 324 interpretable "sample point-molecule" pairs in 2018, 26 were positive (8%). In 2022, this rate was 15.8% (70/443).
In 2018, cytotoxics were found at a concentration below 10 times the limit of detection (LOD) on 11 occasions compared to 33 in 2022, on 12 occasions between 10 and 100 times the LOD compared to 20 in 2022, and on 3 occasions above 100 times the LOD compared to 17 in 2022.
Cytotoxics were mainly detected in the production area (19/26 or 73% in 2018 and 57/70 or 81% in 2022), but also in the dispensing area.

Discussion/Conclusion
There has been an increase in cytotoxic contamination of our unit’s surfaces between 2018 and 2022 (+31% on points analyzed both years).
Between these two dates, we experienced a +10% increase in activity, and we switched to a videodigital control system for preparations on ¾ of our production. This control requires the manipulation of syringes filled with cytotoxics to show them to the camera which validates the volumes drawn. We assume that this may be the cause of cytotoxic spread in the preparation chamber. Indeed, the points collected in 2022 on these systems components were strongly positive, much more than those collected in the automated preparation cabinets, where the control is gravimetric.
The contamination is probably then carried by the chemotherapy bags to the outside of the clean room.
The current technique for cleaning our surfaces does not seem to be sufficiently effective to achieve satisfactory chemical decontamination.
We are therefore going to review our processes and implement an action plan in conjunction with the professional risk management unit and the institution management.

See the poster