Assessment of surface contamination by cytotoxic anticancer drugs in hospital settings

Background
The compounding of cytotoxic anticancer substances (CS) is a high-risk activity that may lead to environmental contamination. In 2021, an initial surface sampling (SS) campaign yielded positive results. Considering changes in staff, practices, and facilities, we reassessed our contamination levels by conducting a new series of SS.

Methods
A total of 30 SS were performed, targeting all high-risk areas within the hospital, including the preparation unit, which comprises two SIEVE isolators, and the care unit. SS was carried out over two days, selected based on the CS investigated and their representativeness of routine activity. SS were sent to an external laboratory for the detection and quantification of 21 CS.

Results
Of the 30 SS performed, 25 (83%) were positive, including 9 (30%) with contamination levels exceeding 10 ng (all cytotoxics combined). Overall, traces of 6 CS were detected out of the 21 tested. Among the samples, 63% were positive for platinum salts, 60% for cyclophosphamide (CP), 30% for fluorouracil (5-FU), 10% for gemcitabine, 10% for ifosfamide, and 10% for cytarabine. 8 samples (27%) were positive for at least 3 CS simultaneously.
The most contaminated sites included: storage boxes in the care unit (500 ng CP; 95 ng 5-FU); isolator lab bench and computer mouse (70 ng gemcitabine; 30 ng 5-FU; 27 ng CP); neoprene gloves (55 ng 5-FU); medication carts (22 ng CP); and transport coolers (12 ng cytarabine). Traces of cytarabine were also detected on a personal smartphone located in the changing room. All CS detected had been handled on the day of sampling or the day before, except for ifosfamide, which had last been used five days earlier.

Conclusions
The presence of CS residues throughout the entire workflow suggests insufficient effectiveness of protective measures. However, the majority of our production is done with vented vial access device, the use of PHASEAL system (ifosfamid) and ready-to-use cyclophosphamide. SS has identified contaminated areas for which the chemical decontamination process is not appropriate. A gradient of decreasing contamination levels was observed from the interior of isolators to the validation room, suggesting that closed-system handling reduces, but does not eliminate exposure. Contamination of transport coolers and storage boxes was partly attributable to non-compliance with cleaning procedures, as revealed by an internal audit conducted in parallel with this campaign. The data also suggest accumulation and persistence phenomena of CS. The detection of cytarabine on a personal item highlights the critical importance of adherence to hand hygiene procedures.

The inter-individual variability in practices, highlighted by this campaign and the audit, underscores the need to improve staff training and evaluation. A follow-up SS campaign will be conducted in 6 months to assess the impact of the corrective measures to be implemented.

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