A signal assay for the detection of genotoxic compounds: application on the urines of cancer patients on chemotherapy and of nurses handling cytotoxic drugs

Turkish nurses' information about, and administration of, chemotherapeutic drugs

AIM

The aim of this study was to determine both the level of information that nurses possessed and the method of administration nurses used during chemotherapeutic drug preparation and administration.

BACKGROUND

While compliance with the regulations related to chemotherapeutic drug preparation and administration seems to be very difficult, it is at the same time vital.

METHODS

This descriptive study was conducted between 1 May 2002 and 1 May 2003 in the chemotherapy administration units of all hospitals in Eskisehir, west Turkey. The sample consisted of 121 nurses. Data were obtained first via questionnaire forms developed by the researchers to learn the level of awareness concerning exposure to chemotherapy. This was then followed up by the completion of observation forms during drug administrations.

RESULTS

The average score for information levels pertaining to nurses' protection of the environment was 7.82 +/- 0.38 of a total of 14 points, and that of self-protection was 7.94 +/- 0.24 of a total of 11 points. Nurses showed that their actual administration method was insufficient according to their level of information, with average administration evaluations of 5.46 for protection of the environment and 6.59 for self-protection. The ratio for nurses' usage of the safety cabinet during the preparation of chemotherapeutic drugs was very low at 14.2%. Only 7.4% of nurses had received in-service education about chemotherapeutics.

CONCLUSION

In order to ensure the taking of sufficient preventive precautions during the preparation and administration of chemotherapeutic agents, hospitals should be required to provide sufficient equipment and to give this precedence in hospital politics.

RELEVANCE TO CLINICAL PRACTICE

Healthcare workers who prepare and administer chemotherapeutic drugs may experience the cytotoxic effects of the drugs through direct skin contact, respiratory and digestive system exposure, and these effects are vital to human life. Thus, it has been recognized that nurses' information and administrations during preparation and administration of chemotherapeutic drugs are of utmost vital importance in removing the harmful effects of chemotherapeutic agents.

Biological and environmental monitoring of hospital personnel exposed to antineoplastic agents: a review of analytical methods

In order to assess occupational exposure of hospital personnel involved in the preparation and administration of antineoplastic drugs, biological and environmental monitoring are essential to identify the main exposure routes and to quantify potential health risks. If workplace contamination cannot be completely avoided, it is of utmost importance to reduce exposure to the lowest possible levels. To this aim, not only do education and training of the exposed subjects play an important role, but accurate standardized sampling techniques and analytical methods are also required. A critical overview of the most significant methods available in the literature is presented and their value is discussed, especially with respect to their sensitivity and specificity. In addition, attention is given to validation procedures and, consequently, to their reliability. The results from the most important surveys carried out at hospital departments are also discussed, with a view to improving both monitoring strategies and moreover working conditions.

Assessment of genotoxic damage in nurses occupationally exposed to antineoplastics by the analysis of chromosomal aberrations

To estimate the genotoxic risk of occupational exposure to antineoplastic drugs, chromosomal aberration (CAs) frequencies in peripheral lymphocytes were determined for 20 nurses handling antineoplastics and 18 referents matched for age and sex. Urinary cyclophosphamide (CP) excretion rates, which are used as a marker for drug handling, were also measured on these nurses. We have observed significant frequencies of CAs (about 2.5-fold increase) including chromatid breaks, gaps, and acentric fragments for nurses handling antineoplastics as compared to control subjects (p < 0.05, p < 0.01, excluding and including gaps, respectively). The mean value of CP excretion rate for 12 nurses was 1.63 microg/24 h, suggesting that when the nurses handled CP (and other antineoplastic drugs) this particular compound was absorbed. Our study has shown that increased genetic damage was evident in nurses, at population level, due to occupational exposure to antineoplastics. Until the effects of handling antineoplastics from low-level exposure are known, it will be important to keep the exposure to a minimum.

Urinary cyclophosphamide excretion and micronuclei frequencies in peripheral lymphocytes and in exfoliated buccal epithelial cells of nurses handling antineoplastics

In this study, urinary cyclophosphamide (CP) excretion rate, as well as micronuclei (MN) in peripheral lymphocytes and in buccal epithelial cells were determined for 26 nurses handling antineoplastics and 14 referents matched for age and sex. In urine samples of 20 out of 25 exposed nurses CP excretion rate was found in a range of 0.02-9.14 microg CP/24 h. Our results of the analyses of CP in urine demonstrates that when the nurses were handling CP (and other antineoplastic drugs) this particular compound was observed in urine. The mean values (+/-SD) of MN frequencies (%) in peripheral lymphocytes from the nurses and controls were 0.61 (+/-0. 32) and 0.28 (+/-0.16), respectively (p<0.01). The mean value (+/-SD) of MN frequency (%) in buccal epithelial cells of nurses was 0.16 (+/-0.19) and also mean MN frequency in buccal epithelial cells for controls was found to be as 0.08 (+/-0.08), (p>0.05). Age, sex and smoking habits have not influenced the parameters analyzed in this study. Handling time of antineoplastics, use of protective equipment and handling frequency of drugs have no effect on urinary and cytogenetic parameters analyzed. No correlation was found between the urinary CP excretion and the cytogenetic findings in nurses. Neither could we find any relationship between two cytogenetic endpoints. Our results have identified the possible genotoxic damage of oncology nurses related to occupational exposure to at least one antineoplastic agent, which is used as a marker for drug handling. As a whole, there is concern that the present handling practices of antineoplastic drugs used in the several hospitals in Ankara will not be sufficient to prevent exposure.

Evaluation of genotoxic potential of styrene in furniture workers using unsaturated polyester resins

Styrene is a widely used chemical, mostly in making synthetic rubber, resins, polyesters, plastics and insulators. Increasing attention has been focused on this compound since experiments using cytogenetic end-points have implicated styrene as a potential carcinogen and mutagen. In order to perform biological monitoring of genotoxic exposure to styrene monomer, we evaluated the urinary thioether (UT) excretion, and sister chromatid exchanges (SCEs) and micronuclei (MN) in peripheral lymphocytes from 53 furniture workers employed in small workplaces where polyester resin lamination processings were done and from 41 matched control subjects. The mean air concentration of styrene in the breathing zone of workers was 30.3 ppm. As a metabolic marker for styrene exposure, mandelic acid + phenylglyoxylic acid was measured in the urine and the mean value was 207 mg/g creatinine. The mean +/- SD value of UT excretions of workers was 4.43 +/- 3.42 mmol SH-/mol creatinine and also mean UT for controls was found to be a 2.75 +/- 1.78 mmol SH-/mol creatinine. The mean +/- SD/cell values of SCE frequency in peripheral lymphocytes from the workers and controls were 6.20 +/- 1.56 and 5.23 +/- 1.23, respectively. The mean +/- SD frequencies (%o) of MN in the exposed and control groups were 1.98 +/- 0.50 and 2.09 +/- 0.35, respectively. Significant effects of work-related exposure were detected in the UT excretion and SCEs analyzed in peripheral blood lymphocytes (p < 0.05 and p < 0.01, respectively). The MN frequency in lymphocytes from the styrene-exposed group did not differ from that in the controls (p > 0.05). Effect of smoking, age and duration of exposure on the genotoxicity parameters analyzed were also evaluated. In conclusion, although our data do not demonstrate a dose-response relationship, they do suggest that styrene exposure was evident and that this styrene exposure may contribute to the observed genotoxic damage in furniture workers.

Biomonitoring of occupational exposures to cytostatic anticancer drugs

Cytostatic anticancer drugs are known as carcinogenic, mutagenic, and teratogenic risk factors for health care workers who are occupationally exposed during the preparation and administration of such drugs. During the last 20 years, several researchers have developed and validated methods to monitor occupational exposure to such agents. This paper reviews the literature with respect to the possible effects on occupationally exposed hospital workers and establishing occupational exposure.

Exposure of oncologic nurses to methotrexate in the treatment of osteosarcoma

Methotrexate is a therapeutic agent used widely for osteosarcoma. We used an extremely sensitive high-performance liquid-chromatography assay to evaluate 112 urine samples obtained from 28 hospital employees during high-dose therapy with methotrexate and during routine care of patients. The highest cumulative urinary excretion was observed when methotrexate infusions were handled in a workbench from which a portion of filtered air was emitted into the room. Remarkable urine contaminations were identified for personnel, including 1 administrative employee who had "stood by" for 2 h in the room where infusions were prepared. Lower methotrexate concentrations were detected in the urine of nurses whose exclusive function was to care for patients. The urine burden in oncologic nurses decreased after a central pharmacy unit was installed. Methotrexate was excreted in the sweat of patients who were under high-dose therapy, and its elimination half-life was 11.1 h (mean maximal concentration = 1.7 micrograms/ml [n = 51). The maximal burden in spontaneous vomit from these patients was 441.5 micrograms/ml, and it declined to 0.24 micrograms/ml 19.5 h after infusion was completed. No methotrexate was detected in personnel who prepared 20-g methotrexate infusions in the central pharmacy unit. We demonstrated that occupational safety depended not only on technical precautions, but on the skills of specifically trained personnel.

Evaluation of micronuclei in exfoliated urothelial cells and urinary thioether excretion of smokers

Mutagens are present in large quantities in the urine of cigarette smokers, thus, their urothelial cells may represent a possible target for absorbed and excreted mutagens. Our aim is to validate the micronucleus (MN) test in exfoliated urothelial cells obtained from urine samples of cigarette smokers. The urinary thioether (UT) test is also carried out on the same individuals in order to find out whether there is any correlation between these two end-points. The mean (+/- SE) MN frequency and UT determination is 1.93 (+/- 0.11)% and 9.71 (+/- 1.61) mmol SH/mol creatinine for 23 smokers, and 0.66 (+/- 0.05)% and 4.20 (+/- 0.56) mmol SH/mol creatinine for 20 nonsmokers. Our results show a higher frequency of micronucleated cells (p < 0.001) and higher excretion of UTs (p < 0.05) in smokers as compared to nonsmokers. Concentrations of UTs and MN frequencies increased with tobacco consumption. The MN frequencies showed only a marginal increase, not significant (p > 0.05), after passive smoking compared to nonsmoking values. There was no significant correlation between MN frequencies and UTs, either in smokers (r = 0.164, p > 0.05) or in nonsmokers (r = -0.018, p > 0.05). Our data demonstrate tobacco-induced chromosome damage in bladder tissue consistent with increased risk of cancer at this site among smokers.

Urinary biological monitoring markers of anticancer drug exposure in oncology nurses

People handling anticancer drugs or their wastes may absorb these potent genotoxic agents. The aim of this study was to determine the utility of some general urinary markers among 24 female oncology nurses handling these drugs in comparison with 25 "unexposed" nurses. The markers were the Salmonella typhimurium reverse and forward mutation assays, total thioethers, and D-glucaric acid. The reverse mutation assay was the most specific and sensitive marker for anti-cancer drug exposure. Use of the marker battery was no great advantage as a screening tool relative to use of the reverse mutation assay alone. Better recording of work practices in nurse work logs would have improved interpretation of results.

Thioethers in urine of sterilization personnel exposed to ethylene oxide

Biological monitoring of exposure to ethylene oxide (EO) was carried out in 31 hospital workers in the sterilization facilities of five hospitals. The excretion of total thioethers was determined in the urine of sterilization workers. An occupational nonexposed group served as a control (n = 31). The air EO level was not monitored routinely, however, peak concentrations of EO up to 200 p.p.m. were detected mainly when the sterilization chambers were open. Our results show a significant difference in urinary thioether excretion between the exposed and control groups (P less than 0.001). Sterilization workers seem to absorb significant quantities of EO. We feel that other alternative and more sensitive methods for detecting thioether metabolites of EO should be carried out to confirm our results.

Detection of contamination with antineoplastic agents in a hospital pharmacy department

The contamination with fluorouracil, cyclophosphamide and methotrexate was studied in a hospital pharmacy department where these drugs were prepared. In the preparation room, air samples were taken before and during preparation of the drugs. Methotrexate was detected in one sample which was collected during preparation (0.3 micrograms/m3). Spot samples were taken in the vertical laminar airflow safety hood before and after preparation of the drugs and after cleaning of the hood. Contamination of the laminar airflow hood was: cyclophosphamide: 1-160 ng/cm2; fluorouracil: 10-62 ng/cm2 and methotrexate: 2-633 ng/cm2. Spot samples from the floor in front of and beneath the laminar airflow hood showed contamination with especially fluorouracil (48-236 micrograms/m2). The gloves used during preparation of the drugs were contaminated mainly with fluorouracil (5-980 ng/cm2). Urine samples from two workers involved in the preparation of the drugs were analysed for unmetabolized cyclophosphamide; it was not detected. Although no uptake of cyclophosphamide was established, it is shown that the methods for measurement of cyclophosphamide, fluorouracil and methotrexate in the preparation room are applicable for the control of occupational exposure to these drugs.

The risks of handling cytotoxic drugs. I. Methods of testing exposure

Results of various biological and physical/chemical tests of the urines or blood of health-care personnel working with cytotoxic drugs are discussed. The outcomes of these tests are conflicting and inconclusive. The physical/chemical tests seem to be an alternative method. However, until now it has not been possible to establish the threshold concentration in urine or blood beneath which no effect has to be expected. Therefore, the interpretation of the concentration of cytotoxic drugs and/or the metabolites in the urine or blood is difficult. As long as one will not be able to provide conclusive data on the health hazards when working with cytotoxic drugs, protective measures have to be taken in order to lower the risk as much as possible.