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Chemo drugs damage HCW chromosomes
Studies show risk, widespread contamination
Nurses and pharmacists who handle chemotherapeutic drugs are unknowingly being exposed to a potential carcinogenic and reproductive hazard, and those with the highest exposures have significant chromosomal abnormalities, according to two recent studies.
The research sheds new light on the risks of chemotherapeutic agents to health care workers that persist even with updated handling policies and safety equipment.
"These findings were not in borderline hospitals but in university hospitals that all endorsed the safe handling practices," says lead author Melissa A. McDiarmid, MD, MPH, DABT, director of the Occupational Health Program at the University of Maryland School of Medicine in Baltimore.
Proper work practices need to be reinforced and clean rooms and closed mixing and dispensing systems need to be adopted to minimize exposure, says Thomas H. Connor, PhD, a research biologist at the National Institute for Occupational Safety and Health in Cincinnati who is lead author of a study that found widespread surface contamination in pharmacy and nursing areas.
Sixty percent of wipe samples in work areas tested positive for contamination with at least one of five antineoplastic drugs in Connor's study. That included carts, trays, countertops, IV bags, and even floors in patient rooms. The highest concentration was found on the lid of a hazardous waste container in a nursing station. About a third (32%) were contaminated with more than one drug, and pharmacy areas tended to be more contaminated than nursing areas.1
Three of 68 exposed workers had measurable concentrations of cyclophosphamide or paclitaxel in their urine, Connor and his colleagues found. In McDiarmid's companion study, nurses and pharmacists were 20% more likely to have an abnormality of chromosome 5 or 7 than a control group if they had 100 or more chemotherapeutic drug handling events. Those involved in the most handling 500 events had a 2.5 increased likelihood of a chromosomal 5 or 7 abnormality. When alkylating agents alone were considered (23% of handling events), the likelihood of chromosomal damage doubled at just 100 events and was almost 7-fold at 200 events.2
This is the first time U.S. researchers have looked at the specific chromosomal markers that are observed in leukemic patients and found important genotoxic changes in nurses and pharmacists handling chemotherapeutic drugs. That should be a wake-up call for greater attention to this hazard, says McDiarmid.
"There needs to be some vigilant attention to the application of the current safe handling guidance," she says. "These are probably the most toxic agents that are present in health care and we need to act like it. They are designed to kill cells. Why are we surprised they can't tell the difference between who is the patient and who is the health care worker?"
Hazards on par with radioactivity
The findings underscore why chemical hazards should be treated with the same high level of concern as radiologic hazards, says McDiarmid.
"We need to realize the high pressure milieu in which chemo is given," says McDiarmid. "Everything needs to get done in a short amount of time . . . I think that promotes short-cuts. We're sacrificing ourselves for the patient.
"If there was genuine respect for these [agents] the way there was for a radiation hazard, I think people would take fewer shortcuts," she says.
For example, health care workers may not be aware that studies have found contamination on the outside of virtually all vials which creates risk for everyone from the person unloading supplies in shipping and receiving to pharmacists and nurses. "As long as you have [contaminated vials], you can do everything else right, but you're going to have some contamination," says Connor.
Placing protective sheeting on the outside of vials may reduce contamination, studies show.3 Other measures to protect health care workers include:
Double-gloving. Health care workers should wear double-gloves when handling hazardous drugs, Connor says. After mixing or administering the drug, the outer glove should be removed and placed in a hazardous waste container. The remaining glove then will be clean and will not contaminate surfaces, he says.
Gowns. Gowns should be worn during compounding, administration, and waste handling, and they should be made of a material that is protective against the hazardous drugs being used. Gowns should not be reused and should be disposed of as hazardous waste.
Closed-system drug transfer devices. These devices can reduce contamination when used with a biologic safety cabinet. However, risk still remains from surface contamination on the outside of vials.
Sterile handling. The careful practices and design of a "clean room" decrease the risk of contamination, Connor says. "In general, the clean room design with proper air flows is a good way of reducing the contamination," he says. "When you're protecting the product from contamination, you're also protecting the worker because conditions in general are much stricter and cleaner."
[Editor's note: The American Society of Health-System Pharmacists provides guidelines on handling hazardous drugs at www.ashp.org/DocLibrary/BestPractices/PrepGdlHazDrugs.aspx.]
1. McDiarmid MA, Oliver MS, Roth TS et al. Chromosome 5 and 7 abnormalities in oncology personnel handling anticancer drugs. J Occup Environ Med 2010;52:1028-1034.
2. Connor TH, DeBord DG, Pretty JR et al. Evaluation of antineoplastic drug exposure of health care workers at three university-based US cancer centers. J Occup Environ Med 2010;52:1019-1028.
3. Schierl R, Herwig A, Pfaller A, et al. Surface contamination of antineoplastic drug vials: Comparison of unprotected and protected vials. Am J Health Syst Pharm 2010;67:428-429.