Applicability of the comet assay in evaluation of DNA damage in healthcare providers' working with antineoplastic drugs: a systematic review and meta-analysis

The Comet Assay as a Tool in Human Biomonitoring Studies of Environmental and Occupational Exposure to Chemicals-A Systematic Scoping Review

Biomonitoring of human populations exposed to chemical substances that can act as potential mutagens or carcinogens, may enable the detection of damage and early disease prevention. In recent years, the comet assay has become an important tool for assessing DNA damage, both in environmental and occupational exposure contexts. To evidence the role of the comet assay in human biomonitoring, we have analysed original research studies of environmental or occupational exposure that used the comet assay in their assessments, following the PRISMA-ScR method (preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews). Groups of chemicals were designated according to a broad classification, and the results obtained from over 300 original studies (n = 123 on air pollutants, n = 14 on anaesthetics, n = 18 on antineoplastic drugs, n = 57 on heavy metals, n = 59 on pesticides, and n = 49 on solvents) showed overall higher values of DNA strand breaks in the exposed subjects in comparison with the unexposed. In summary, our systematic scoping review strengthens the relevance of the use of the comet assay in assessing DNA damage in human biomonitoring studies.

Factors associated with internal contamination of nurses by antineoplastic drugs based on biomonitoring data from a previous study

Internal contamination of healthcare professionals by antineoplastic drugs (ADs) remains a current occupational health issue, particularly because these compounds are classified as dangerous to handle by the NIOSH. In order to improve preventive actions, a study of the factors associated with this internal contamination was conducted among nursing staff in health care institutions. This study is a statistical analysis of metadata from a cross-sectional observational study conducted among nurses in two French hospitals. The internal contamination of each nurse was assessed in a previous study and was defined by whether or not at least one studied AD was detected in at least one urine sample. Three urine samples and a self-questionnaire were collected for each participant. Analysis of five ADs (cyclophosphamide, ifosfamide, metabolite of 5-fluorouracil, methotrexate, doxorubicin) were performed by liquid chromatography coupled to tandem mass spectrometry. A multivariate stepwise descending regression model was used to determine factors associated with internal contamination by coupling data from a self-questionnaire with internal contamination data. A total of 74 nurses participated to the study and 68 were included for this work: 39 nurses with and 29 without detectable internal ADs contamination. Two protective factors of internal contamination could be identified: a high "glove wearing score" (OR: 0.957; 95%CI: 0.93-0.98; p < 0.01) and a high "total number of years handling ADs and/or caring for patients treated with ADs" (OR: 0.797; 95%CI: 0.67-0.91; p < 0.01). In addition, three factors contributing to internal contamination were identified, namely "feeling sufficiently informed about tasks exposing to ADs" (OR: 9.585; 95%CI: 2.23-57.05; p < 0.01), "disposal of a waste bin containing equipment used for administration of the ADs studied" (OR: 8.04; 95%CI: 1.87-46.08; p < 0.01) and "changing sheets and/or making bed of a patient treated by one of the ADs studied" (OR: 10.479; 95%CI: 1.43-133.30; p < 0.05). Thus, the use of gloves when handling ADs directly or indirectly and the contaminating nature of certain tasks should be taken into account when (1) implementing preventive actions in health care services and (2) training and informing exposed staff. Further studies would be desirable to confirm these results and extend them to other professional categories.

Systematic review of genotoxicity induced by occupational exposure to antineoplastic drugs

With increasing numbers of cancer cases, the use of antineoplastic agents is expected to rise. This will be accompanied by an increase in occupational exposure, which can cause unwanted health effects in workers. Our aim was to give an overview of genotoxic and epigenetic effects after occupational exposure to antineoplastic agents and to assess the concentration-effect relation. Four databases were searched for papers investigating genotoxic and/or epigenetic effects of occupational exposure to antineoplastic agents. Out of the 245 retrieved papers, 62 were included in this review. In this systematic literature review, we confirmed that exposure of healthcare workers to antineoplastic agents can lead to genotoxic damage. However, we observed a lack of data on exposure as well as genotoxic and epigenetic effects in workers other than healthcare workers. Furthermore, gaps in the current knowledge regarding the potential epigenetic effects caused by antineoplastic drug exposure and regarding the link between internal antineoplastic drug concentration and genotoxic and epigenetic effects after occupational exposure to antineoplastic agents were identified, offering a first step for future research.

The meta-analysis of cytogenetic biomarkers as an assessment of occupational risk for healthcare workers exposed to antineoplastic drugs

OBJECTIVE

Antineoplastic drugs (ADs) are widely used in clinical practice and have been demonstrated to be effective in treating malignant tumors. However, they carry a risk of cytogenotoxicity for healthcare workers. Studies have reported that genotoxic biomarkers can be applied to assess the occupational health status of healthcare workers at an early stage, but results of different studies are variable. The objectives of the review were examine the association between long-term exposure to ADs and cytogenetic damage to healthcare workers.

METHODS

We systematically reviewed studies between 2005 and 2021 using PubMed, Embase and Web of Science databases that used cytogenetic biomarkers to assess occupational exposure to ADs in healthcare workers. We used RevMan5.4 to analyze the tail length parameters of the DNA, frequency of the chromosomal aberrations, sister chromatid exchanges and micronuclei. A total of 16 studies were included in our study. The studies evaluate the quality of the literature through the Agency for Healthcare Research and Quality.

RESULTS

The results revealed that under the random-effects model, the estimated standard deviation was 2.37 (95% confidence interval [CI] 0.92-3.81, P = 0.001) for the tail length parameters of the DNA, 1.48 (95% CI 0.71-2.25, P = 0.0002) for the frequency of chromosomal aberrations, 1.74 (95% CI 0.49-2.99, P = 0.006) for the frequency of sister chromatid exchanges and 1.64 (95% CI 0.83-2.45, P < 0.0001) for the frequency of micronuclei.

CONCLUSIONS

The results indicate that there is a significant association between occupational exposure to ADs and cytogenetic damage, to which healthcare workers should be alerted.

Development and application of a liquid chromatography coupled to mass spectrometry method for the simultaneous determination of 23 antineoplastic drugs at trace levels

The goal of this study was to develop a method for the simultaneous quantification of 23 commonly used antineoplastic drugs in a hospital pharmacy, using ultra-high pressure liquid chromatography separation coupled to tandem mass spectrometry detection (UHPLC-MS/MS). The following drugs were investigated: 5-fluorouracil, cytarabine, ganciclovir, gemcitabine, dacarbazine, methotrexate, pemetrexed, busulfan, topotecan, rentitrexed, ifosfamide, cyclophosphamide, etoposide, irinotecan, doxorubicin/epirubicin, vincristine, docetaxel, paclitaxel, daunorubicin, idarubicin, vinblastine, oxaliplatin and carboplatin. The chromatographic separation was performed on a phenyl-hexyl column (2.1 ×100 mm, 1.7 µm) with a gradient elution of methanol and water containing 10 mM ammonium formate adjusted to pH 4.9. All compounds were analyzed in less than 13 min and detected with a triple quadrupole mass spectrometer operating in MRM mode. Limits of detection (LODs) and limits of quantification (LOQs) were comprised between 0.01 and 5 ng.mL^-1, and between 0.5 and 5 ng.mL^-1, respectively. Accuracies ranged between 117% and 83% at the LOQ, intermediate and upper LOQ concentrations, with relative standard deviations (RSD) inferior to 8%, for all the antineoplastic drugs. Finally, the UHPLC-MS/MS method was successfully applied to the analysis of surface samples to evaluate the chemical contamination by these highly toxic compounds in a chemotherapy preparation unit in a hospital pharmacy with the purpose of monitoring the exposure of health care professionals.

Safe Handling of Antineoplastic Drugs During Allergy Diagnostic Workup and Desensitization: A Single Experience of the Allergy Department in a Tertiary Hospital

The increased use of antineoplastic drugs has been associated with a rising number of hypersensitivity reactions to these drugs, which has led to a growth in the demand for assistance from allergy services. The involvement of an allergist is essential to ensure that these patients with hypersensitivity reactions continue to be able to receive appropriate first-line treatment. Chemotherapy and biological agents have specific handling requirements and all the allergy departments involved in the diagnosis and therapeutic management of patients reacting to these drugs should find the means to guarantee safety. There are currently several guidelines on the safe handling of hazardous drugs for healthcare workers. However, specific recommendations are lacking for reducing occupational exposure in staff working in the allergy departments and managing these drugs for the diagnosis and management of hypersensitivity reactions. This review article focuses on the safe handling strategy of the allergy department in the Ramón y Cajal University Hospital and provides details of its implementation and experience over 10 years. This protocol could improve the knowledge of safe handling of antineoplastic drugs in allergy procedures.

Effect of occupational exposure to antineoplastic drugs on DNA damage in nurses: a cross-sectional study

BACKGROUND

Although the therapeutic effect of antineoplastic drugs is incontestable, these agents can also potentially act as carcinogens, mutagens and/or teratogens in people. The aim of this study was to assess the effect of occupational exposure to antineoplastic drugs on DNA damage, assessed by the comet assay and cytokinesis-block micronucleus (CBMN) assay, in nurses.

METHODS

The cross-sectional study enrolled 305 nursing staff members from 7 public hospitals in Shenzhen who handled antineoplastic drugs, and 150 healthy nursing staff members who were not exposed to antineoplastic drugs as the control group. DNA damage was assessed by the comet and CBMN assay. Multiple linear regressions and logistic regressions models were used to analyse the effect of occupational exposure to antineoplastic drugs on DNA damage.

RESULTS

After adjustment for confounding factors, compared with non-exposure to antineoplastic drugs, exposure to antineoplastic drugs was positively related to tail moment, olive moment, tail length and tail DNA per cent, and adjusted β or OR (95% CI) was 0.17 (0.08 to 0.26), 0.18 (0.10 to 0.27), 1.03 (0.47 to 1.60) and 1.16 (1.04 to 1.29) (all p<0.05). Moreover, similar significant relationships were observed for the biomarkers of the CBMN assay. Additionally, other than age, there was no interaction between antineoplastic drug exposure and other variables for the levels of biomarkers of the CBMN assay and the comet assay.

CONCLUSIONS

The present results showed that exposure to antineoplastic drugs was positively related to the risk of DNA damage in nurses. The results imply that occupational exposure to antineoplastic agents is an important global public health problem that requires urgent attention.

Occupational exposure assessment in professionals who manipulate and administer antineoplastic drugs in a university hospital in Southern Brazil

INTRODUCTION

Our goal was to demonstrate the effects of occupational exposure to antineoplastic drugs on oxidative stress parameters and DNA damage in health professionals who manipulate and administer antineoplastic drugs in a University Hospital in Southern Brazil.

METHODS

The case-control study with a longitudinal design, involved 64 individuals, 29 of them pharmacists, pharmacy technicians and nurses who were occupationally exposed to antineoplastic drugs and 35 professionals who were not exposed. Gene mutations were determined by micronucleus from salivary fluid; DNA damage by comet assay and oxidative stress parameters in whole blood were also evaluated.

RESULTS

All workers exposed to antineoplastic drugs used personal protective equipment (PPE). It was demonstrated that the total nonprotein thiol and thiobarbituric acid reactive substances levels showed interaction between group and time, with higher levels one week after handling/administration of antineoplastic drugs in the exposed group (GEE, p ≤ 0.0001 and p = 0,013, respectively). Additionally, there was a group effect on the activities of the catalase and glutathione peroxidase antioxidant enzymes (GEE, p = 0.027 and p ≤ 0.0001, respectively), and workers occupationally exposed to antineoplastic drugs had higher enzyme activities compared to those not exposed. No genotoxic damage was demonstrated through the evaluated parameters.

CONCLUSIONS

Despite the correct use of PPE, professionals occupationally exposed to antineoplastic drugs were more susceptible to oxidative stress than those not exposed. The evaluation of the studied parameters is especially important for the definition of conducts and practices in the area, always in search of guaranteeing the establishment of a rational policy to protect workers' health.

Investigating landfill leachate toxicity in vitro: A review of cell models and endpoints

Landfill leachate is a complex mixture characterized by high toxicity and able to contaminate soils and waters surrounding the dumpsite, especially in developing countries where engineered landfills are still rare. Leachate pollution can severely damage natural ecosystems and harm human health. Traditionally, the hazard assessment of leachate is based on physicochemical characterization but the toxicity is not considered. In the last few decades, different bioassays have been used to assess the toxicity of this complex matrix, including human-related in vitro models. This article reviews the cell bioassays successfully used for the risk assessment of leachate and to evaluate the efficiency of toxicity removal of several processes for detoxification of this wastewater. Articles from 2003 to 2018 are covered, focusing mainly on studies that used human cell lines, highlighting the usefulness and adequacy of in vitro models for assessing the hazard involved with exposure to leachate, particularly as an integrative supporting tool for chemical-based risk assessment. Leachate is generally toxic, mutagenic, genotoxic and estrogenic in vitro, and these effects can be measured in the cells exposed to already low concentrations, confirming the serious hazard of this wastewater for human health.

Important exposure controls for protection against antineoplastic agents: Highlights for oncology health care workers

BACKGROUND

A great number of antineoplastic drugs (ANPDs) are used globally in cancer treatment. Due to their adverse health effects, occupational exposure to ANPDs is considered a potential health risk to health care workers.

OBJECTIVE

The current study aimed to evaluate safe-handling practices of ANPDs, exposure controls, and adverse health implications for health care providers exposed to ANDPs.

METHODS

Prevention measures, including engineering, administrative, and work practice controls, as well as personal protective equipment (PPE), were recorded daily through a questionnaire for six weeks. Acute adverse health effects experienced by health care workers were also documented.

RESULTS

The implemented exposure controls for preparation, administration, cleaning, and waste disposal were not in accordance with the safe handling guidelines. Central nervous system disorders (26.33%) were the most frequent acute adverse effects reported by health care workers. A significant correlation was found between the number of experienced adverse effects and handling characteristics, including the number of preparations (r = 0.38, p < 0.05), dose, and the number of prepared drugs (r = 0.46, p < 0.01 and 0.39, p < 0.05), and working hours in different locations of oncology setting for six weeks (preparation room: r = 0.38, P < 0.05, treatment room: r = 0.46, P < 0.01, patient room: r = 0.63, P < 0.01, and station: r = 0.68, P < 0.01).

CONCLUSIONS

Due to inadequate control measures, oncology health care workers were in danger of exposure to ANPDs and experienced acute adverse health effects. Implementation of appropriate exposure controls is required to prevent occupational exposure to ANPDs.

Surface contamination with ten antineoplastic drugs in 83 Canadian centers

PURPOSE

The aim of this study was to monitor environmental contamination by 10 antineoplastic drugs in Canadian oncology pharmacy and patient care areas. The secondary objective was to explore the impact of factors that may explain contamination.

METHODS

Twelve standardized sites were sampled in each center (six in the pharmacy and six in patient care areas). Each sample was prepared to allow quantification of seven antineoplastic drugs (cyclophosphamide, ifosfamide, methotrexate, cytarabine, gemcitabine, 5-fluorouracil, irinotecan) by UPLC-MS-MS. Docetaxel, paclitaxel and vinorelbine were also detected, but not quantified due to sensibility limitations. The impact of some factors was evaluated compared with a Kolmogorov-Smirnov test for independent samples.

RESULTS

Eighty-three Canadian centers were recruited in 2017. A total of 953 surfaces were sampled, 495 in pharmacy and 458 in patient care areas. Cyclophosphamide was most often found on surfaces (36% of samples positive, 75th percentile 0.0040 ng/cm²). The arm rest (81.7% of samples positive for at least one antineoplastic drug), the front grille inside the hood (78.3%) and the floor in front of the hood (61.4%) were more frequently contaminated. Centers who prepared more antineoplastic drugs per year had higher concentration on different surfaces ( p < 0.0001).

CONCLUSION

Despite growing awareness and implementation of new safe handling guidelines, healthcare centers' surfaces remain contaminated with traces of many antineoplastic drugs. The use of personal protective equipment remains indisputable. Performing an annual monitoring remains a good indicator to monitor trends over time and to compare with similar centers.

Meta-analysis of chromosomal aberrations as a biomarker of exposure in healthcare workers occupationally exposed to antineoplastic drugs

Many antineoplastic drugs used to treat cancer, particularly alkylating agents and topoisomerase inhibitors, are known to induce genetic damage in patients. Elevated levels of chromosomal aberrations, micronuclei, and DNA damage have been documented in cancer patients. Elevations in these same biomarkers of genetic damage have been reported in numerous studies of healthcare workers, such as nurses and pharmacists, who routinely handle these drugs, but results vary across studies. To obtain an overall assessment of the exposure effect, we performed a meta-analysis on data obtained from peer-reviewed publications reporting chromosomal aberration levels in healthcare workers exposed to antineoplastic drugs. A literature search identified 39 studies reporting on occupational exposure to antineoplastic drugs and measurement of chromosomal aberrations in healthcare workers. After applying strict inclusion criteria for data quality and presentation, data from 17 studies included in 16 publications underwent meta-analysis using Hedges' bias-corrected g and a random-effects model. Results showed the level of chromosomal aberrations in healthcare workers exposed to antineoplastic drugs was significantly higher than in controls. The standardized mean differences (difference of means divided by within sd) from all studies were pooled, yielding a value 1.006 (unitless) with p<0.001. Thus, in addition to the documented genotoxic effects of antineoplastic drugs in cancer patients, this meta-analysis confirmed a significant association between occupational exposure to antineoplastics during the course of a normal work day and increases in chromosomal aberrations in healthcare workers. Based on the studies reviewed, we were unable to accurately assess whether appropriate use of protective measures might reduce the incidence of genetic damage in healthcare workers. However, given the potential for increased cancer risk linked to increases in chromosomal aberrations, the results of this study support the need to limit occupational exposure of healthcare workers to antineoplastic drugs as much as possible.