Summary

Some antineoplastics (ANPs), used in cancer treatment, are themselves classified as carcinogens and can also have other toxic effects on workers who handle them. The incidence of cancer and the number of people living with cancer continue to increase, which means that ANP use and the number of workers potentially exposed to these drugs may well rise, too. A study conducted by the pharmaceutical practice research unit of the Centre hospitalier universitaire Sainte-Justine has shown that samples taken from surfaces touched by nursing and pharmacy staff contained ANP residues. There are no data, however, on the exposure of hygiene and sanitation (HS) staff to these drugs. Several occupational health and safety agencies have noted that for these employees there is a significant potential risk of exposure through skin contact. The primary objective of this study was to assess potential exposure to commonly used ANPs by measuring the contamination of surfaces frequently touched by hygiene and sanitation workers performing tasks in a hospital setting. The secondary objectives were to explore the feasibility and acceptability to staff of taking hand-wipe samples, and to validate the analysis of seven ANPs in addition to the three for which an analysis method was already available at the Centre de toxicologie du Québec (CTQ).

Two leading cancer hospitals agreed to take part in the study. The sampling sites were chosen following preliminary visits to observe the tasks performed by HS department staff in each hospital. While the preliminary hospital visits were going on, the CTQ laboratory team validated the addition of seven ANPs^[1] to the existing analytical method (ultra-high performance liquid chromatography coupled with mass spectrometry ) already being used for three ANP drugs.^[2] The samples were taken by surface swabs, generally on a standardized 600 cm² area. At each hospital, from two to 61 samples were taken in three oncology departments: the pharmacy, the outpatient clinic and the inpatient unit, at some twenty sites. The swabs were taken before the surfaces were cleaned, at the start of the HS staff’s shift, on two days in the same week; sampling of HS equipment was done after use, however. Swabs were taken from the hands of nine HS staff members, 15 nursing staff members and 14 oncology pharmacy staff members. Descriptive analyses are presented first for the proportion of positive samples (above the detection threshold) and then for measured concentrations for which values below the detection limit were assigned using a Bayesian model and a Markov chain engine (Tool 3 on the Expostats site). Lastly, logistic regressions were run to explore the factors associated with detection of the ANPs on surfaces.

At least one ANP was detected in 61% of the 212 samples taken from surfaces. The two most frequently identified were cyclophosphamide and gemcitabine, followed by 5-fluorouracil and irinotecan. The highest concentrations were found in the outpatient clinics for five ANPs (5‑fluorouracil, irinotecan, cyclophosphamide, gemcitabine and ifosfamide). Floors, patient toilet seats and sinks, as well as the covers of cytotoxic waste bins were some of the most contaminated sites in terms of the proportion of positive samples, measured concentrations and number of ANPs detected in the same sample. The highest concentrations of five of the seven quantified ANPs were found on floors, and three of the sites had the highest concentrations of total load (total amount) of ANPs (floors, toilet seats, waste bin covers). The highest concentrations of the other two quantified ANPs were measured on the control panel of an infusion pump and on a door handle.

The hand-wipe samples revealed ANPs on eight of 39 participants (21%), including six nursing staff members and one participant from each of the other two staff categories (HS and pharmacy). Whereas all the nursing and pharmacy staff reported they had taken training on handling hazardous drugs, none of the nine HS staff members had received such training. A high proportion of staff members said they always wore gloves, but a few noted they wore them only for certain tasks. All the pharmacy staff said they washed their hands with soap and water, but from 20% to 25% of the other staff members said they only used alcohol, which is less effective in reducing chemical contamination.

This study has, for the first time in Canada, estimated ANP contamination of work surfaces touched by hygiene and sanitation workers in a hospital setting. It highlights potentially significant exposure. While it does not prove worker exposure to or absorption of ANPs, the results raise questions about current hazardous drug handling practices and point toward a range of preventive initiatives to be developed and measures to be implemented. Two initiatives worth mentioning are training for HS staff on the handling of hazardous drugs and an analysis of hygiene and sanitation techniques and work equipment focused on optimizing prevention of contamination from these drugs. The study also validated the analysis of seven additional ANPs, while testing the acceptability, to staff, of detecting skin contamination through hand-wipe samples. The study results will be useful in guiding efforts to prevent exposure to hazardous drugs in the health care sector.