Health care workers’ exposure to oncology drugs creates risk, need to reinforce safe handling
‘We allow people to be exposed to known carcinogens [but] safety practice is voluntary’
Evidence continues to accumulate that oncology drugs used to treat cancer patients pose a risk to health care workers.
“We have recommended safe practices and guidance for 30 years, but now we have better documentation,” says Melissa A. McDiarmid, MD, MPH, DABT, director of occupational and environmental medicine at the University of Maryland in Baltimore.
For instance, pharmacists and nurses who prepare antineoplastic agents in their work practice have the highest potential exposure to the drugs.
“We now can prove what was assumed to be true before,” McDiarmid says. “That’s good news for health care workers because it means there can be more buy-in from both leadership in terms of investing and from occupational and employee health and health care workers to comply with handling practices.”
For example, one study showed detectable oxidative DNA damage in pharmacy technicians exposed to antineoplastic drugs.1
“One of the ways we knew these drugs were toxic was from the secondary, unplanned effects in patients treated with the drugs,” McDiarmid notes. “Over the years we’ve used observations from treated patients to predict or hypothesize in lesser exposed drugs what potential effects might befall workers who handle these drugs.”
Drugs can cause cancer while treating it
Antineoplastic drugs can cause cancer even as they’re used to treat cancer: “Treated patients develop second malignancies in the course of treatment,” she says. “For them, the risk-benefit ratio is reasonable because the alternative is a more serious illness or death.”
Researchers and health care professionals wondered whether the small theoretical, aerosolized exposures to the drugs created enough exposure to be a risk to health care workers, McDiarmid says.
HCWs have much less exposure to the drugs than do their cancer patients, but that doesn’t mean their risk is minimal.
“We know from studies the schedule — frequency and time period over which someone is exposed may be important for cancer development,” McDiarmid says. “Large numbers of oncology nurses and pharmacists might be getting a small amount of exposure on their skin, and we do not know they’re exposed.”
Exposure that occurs daily over a long period of time can be a significant risk, she adds.
Research also demonstrates that some HCWs who work with anti-cancer drugs test positive for the drugs in their urine. “This suggests there is ongoing exposure,” she says.
McDiarmid was involved in a study showing that occupational exposure to antineoplastic drugs appears to increase risk of congenital malformations and miscarriage, as well as increase risk of infertility.2
A separate study showed an increased risk of miscarriage in nurses handling chemotherapy agents.3
Hospital employee health professionals should heed the evidence regarding infertility and miscarriages and find alternative work practices for workers who are concerned about reproductive risk or who are planning to have a baby, she suggests.
“There should be employee health policies for handling this situation,” McDiarmid advises. “Talk with workers about alternative duty and how to think about this situation before someone becomes pregnant.”
Policy decisions could include having these workers continue working in oncology, but without handling the drugs. “There has to be official notifications, and employee health would handle all of this,” McDiarmid says.
Chromosome damage
Another recent study found that oncology personnel handling anti-cancer agents had a dose-related increase in the incident rate ratio for aberrations in chromosomes 5, 7 and 11.4
“I worked on a cancer outcome concern area, looking at one of the early markers of genotoxic exposure, which is alteration of chromosomes,” McDiarmid explains.
Researchers were concerned that general chromosome abnormalities might be caused from smoking or hazardous hobbies.
“There was this nagging worry,” McDiarmid says. “The unique thing our study did was use the exact same markers in chromosomes that cancer patients get as a result of their treatment with these drugs — abnormalities in chromosomes 5 and 7 — and we found an excess of these in oncology workers who handle these drugs.”
The excessive amount related to their frequency of handling the drugs: the more a worker handled, the more abnormalities were found, she adds.4
“We had workers keep a diary for six weeks to capture in real time their exposure to the drugs,” she says. “That was one of the big strengths of the study — that they didn’t have to remember how many times they handled the drug.”
While the absolute numbers were not particularly alarming, the evidence from a population perspective was troubling, she notes.
“All of these oncology workers were employed at safe handling organizations,” McDiarmid says. “We used psychiatric nurses as controls because they don’t handle these drugs.”
Research like this informs the growing consensus that abnormalities found in workers who handle anti-cancer drugs indicates a problem related to the drugs and not to other environmental factors. “On an individual basis it’s not predictive, but on the population basis, researchers have found it is predictive of future risk,” McDiarmid says.
Reducing the risk
The next question from a hospital employee health perspective is: What can hospitals do to reduce exposure and risk?
First, they should continuously educate and reinforce safe handling guidelines. This requires more than an annual computer training update, McDiarmid says.
“For other types of standards, it’s okay to do it with the computer,” she says. “But we’re talking about really complex safety behaviors like manipulating drugs that come as a solid and then introducing a liquid into the vial under pressure and reconstituting it into a solid.”
A good training strategy is to teach workers safe handling through dry runs and practices. Use a fluorescent dye — in a vial that oncology personnel use — to follow the same procedures used in handling the anti-cancer drugs. After they complete the practice activity, turn on a black light to see if there are any droplets – suggesting exposure, McDiarmid suggests.
“This is a way for people to get a sense of their technique,” she explains.
For ongoing training, hospitals can have observers watch oncology personnel handling the drugs during a typical work day. Observers can make certain corners aren’t cut when workers are in a hurry.
“We don’t know if the current safety recommendations are good enough, but before we can say what we’re doing isn’t protective, we have to meet the current standards and then see if we still have a problem,” McDiarmid says.
“It’s not that people aren’t trying to do it correctly, but there always will be folks in a hurry,” she adds. “And people you think are doing it correctly might have some contamination of the work surface or an unrecognized spill.”
In that regard, a recent study showed that nurses and other health care workers who administer antineoplastic drugs in health care settings are not following safe handling practices. For instance, 80% of those surveyed reported not always wearing two pairs of chemotherapy gloves and 15% did not always wear even one pair. Also, 42% said they failed to always wear non-absorbent gowns with closed front and tight-fitting cuffs.5
It would also help if the Occupational Health and Safety Administration enforced safe handling practices as some states do, McDiarmid says.
“On a rare occasion, OSHA has cited problems with hazard drugs,” she notes.
But OSHA’s own language on the subject is considered guidance and voluntary, so any enforcement is done under other rules, she adds.
“There is a new movement in half of the states to pass laws to enforce [safe handling] guidance,” McDiarmid says. “I think we’re moving in that direction because there is recognition that this is serious — I can’t think of another industry where we allow people to be exposed to known carcinogens and safety practice is voluntary.”
References
- Huang YW, Jian L, Zhang MB, et al. An investigation of oxidative DNA damage in pharmacy technicians exposed to antineoplastic drugs in two Chinese hospitals using the urinary 8-OHdG assay. Biomed Environ Sci 2012;25(1):109-116.
- Connor TH, Lawson CC, Polovich M, McDiarmid MA. Reproductive health risks associated with occupational exposures to antineoplastic drugs in health care settings: a review of the evidence. J Occup Environ Med 2014;56(9):901-910.
- McBride D. Risk of miscarriage is increased for nurses handling chemotherapy. ONS Connect 2012;27(4):22.
- McDiarmid MA, Rogers B, Oliver MS. Chromosomal effects of non-alkylating drug exposure in oncology personnel. Environ Mol Mutagen 2014;55(4):369-374.
- Boiano JM, Steege AL, Sweeney MH. Adherence to safe handling guidelines by health care workers who administer antineoplastic drugs. J Occup & Environ Hygiene 2014;11(11):728-740.
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