Marie Petit

Christophe Curti

Manon Roche
email: manon.roche@univ-amu.fr.tel

Marc Montana

Charleric Bornet

Patrice Vanelle

Petit Marie

Curti Christophe

Roche Manon

Montana Marc

Bornet Charleric

Vanelle Patrice

Environmental monitoring by surface sampling for cytotoxics: a review

Keywords: cytotoxic drugs, surface sampling, chromatography, hospital

Introduction

In recent decades, cancer survival has improved due to advances in cancer treatment by chemotherapy.Unfortunately, treated patients suffer from significant side effects, because the cytotoxic activity of anticancer drugs also extends tonormal cells. Healthcare workers'occupational exposure to cytotoxic drugs has been recognized as a potential health hazard since the 1970s [START_REF] Ng | Possible hazards of handling antineoplastic drugs[END_REF][START_REF] Donner | Possible risk of working with antineoplastic drugs in horizontal laminar flow hoods[END_REF]. Hospital personnel involved in the preparation or administration of cytotoxic agents is exposed to a wide variety of antineoplastic substances. The precautionary principle requires that exposure should be as low as possible [START_REF] Turci | Residual hazard assessment related to handling of antineoplastic drugs: safety system evolution and quality assurance of analytical measurement[END_REF], and minimizingexposureappears to be a real challenge. Numerouspublished guidelines exist, like the Good Manufacturing Practices in France (ANSM 2007) or those of several other countries (OSHA 1999;[START_REF] Schierl | Guidance Values for Surfaces Monitoring of Antineoplasic Drugs in German Pharmacies[END_REF][START_REF] Randolph | NIOSH) Hazardous Drugs in Health Care Settings -Recognition and Control[END_REF][START_REF] Easty | Safe handling of cytotoxics: guideline recommendations[END_REF]. Several good occupational hygiene practices were also published worldwide, as World Health Organization regional office for European Union countries (WHO Europe 2002). Following the US National Institute for Occupational Safety and Health (NIOSH) publication, many healthcare organizations (American Society of Health-System Pharmacists 2006; International Society of Oncology Pharmacy Practitioners 2007; USP <797> 2004; Working Committee on the Safe Handling of Hazardous Drugs 2008) revised their guidelines, policies and procedures in order to enhance safety for care workers (National Institute for Occupational Safety and Health 2004). However, despite compliance with safety directives contamination can occur.

Environmental monitoring is essential to assess the risk of contamination in order to take measuresto improve working conditions through effective cleaning or protection of cytostatic drugs handlerespecially. Even though hospital personnelmay be exposed to antineoplastic agents by inhalation or by inadvertent ingestion (hand-to-mouth contamination for example), direct skin contact appears to be the primary path of exposure.

To ensure accurate risk assessment, a monitoring strategy is recommended, withthe following conditions [START_REF] Turci | Biological and environmental monitoring of hospital personnel exposed to antineoplastic agents: a review of analytical methods[END_REF]): sources of contamination in working areas must be identified. The efficacy of personal protective equipment and biological safety cabinets (BSC) must be verified. Contamination of other areas adjacent to the area of preparation and administration rooms must be monitored and controlled.

Information on work activities should be compiled to allow different periods to be compared.

Rapid, reliable and validated analytical methods are needed to ensure safe handling of these dangerous drugs by reducing healthcare workersexposure to the lowest possible level. While the literature covers numerous analytical methods of environmental monitoring, few authors in the past carried out a formalized validation on their assay. Most of them were reviewed in 2003 (Turciet al. 2003). Only more recent studies include validation procedures using quality controls (QCs). Several techniques were developed for the detection of a single compound, but assay techniques have since tended towards simultaneous detection of several compounds (multicompound technology). Since workers are usually exposed to a large number of drugs, studies focusedon the most toxic (Group 1 IARC) and the most frequently prescribed drugs.

Biological and environmental monitorings are essential to identify the potential paths of exposure and to improveprocedures. Moreover, generalization and standardization of environmental monitoring allows theestablishment of guidance values, useful tool for occupational safety. Considering the current scientific knowledge limitation on toxicity of chronic exposure to nanomolar quantities of cytotoxic drugs,these guidance values are actually based on comparison of results of environmental monitoring. This risk assessment requires specific standardized sampling techniques and analytical methods. In this review, a critical overview of the main methods of environmental monitoring available in the literature is presented. In addition, the procedures that have been validated as ensuring reliability are highlighted. The results of the largest surveys in hospital departments are also cited with a view to improving both monitoring strategies and working conditions.

Cytotoxic drugs covered by environmental sampling

Cytotoxic chemotherapeutic agents can be divided into several classes (OSHA 1999;[START_REF] Turci | Biological and environmental monitoring of hospital personnel exposed to antineoplastic agents: a review of analytical methods[END_REF].

Alkylating agents forming covalent bonds with DNA and RNA and leading to the formation of adducts.

They include nitrogen mustards (such as cyclophosphamide (CP), and ifosfamide (IF)), derivatives of platinum (such as cisplatin (Pt)) and nitrosoureas (such as the carmustine).

Antimetabolites are nucleotide structural analogs and are incorporated into cellular components, inhibiting nucleic acids synthesisand leading to cell death. They include antifolates (such as methotrexate (MTX)), pyrimidine analogues (such as cytarabine (Cyt), gemcitabine (Gem) and 5-fluorouracil (5FU)) and purine analogs (such as fludarabine).

Topoisomerase inhibitors are designed to be insertedbetween the pairs of bases of DNA and to disrupt the synthesis and / or function of nucleic acids. Topoisomerase I inhibitors are derived from camptothecins (such as topotecan(Top) and irinotecan (Iri)) and topoisomerase II inhibitorscontain anthracyclines (such as doxorubicin (Dox) andepirubicin (Epi)) and epipodophyllotoxin derivatives (such as etoposide (Eto)).

Finally, anti-proliferative agents disrupting mitotic spindle include taxanes (such as paclitaxel(Pac)and docetaxel (Doc)) and vinca-alkaloids (such as vincristine (VCR)).

Several cytostatic drugs are classified as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer (IARC)(International Agency for Research on Cancer 2016). This classification (Table 1) is based on epidemiological studies showing the development of secondary tumors in cancer patients treated with these drugs and primary tumors in patients treated with medications for other purposes. Several cytotoxic drugs are classified by IARC in group 2A and 2B (probably and possibly carcinogenic to humans, respectively).

Antimetabolites and mitotic spindle agents are not classifiable as carcinogenic to humans (Group 3). Nevertheless, they remain mutagenic and teratogenic. A wide variety of these drugs were analyzed for environmental monitoring (National Institute for Occupational Safety and Health 2014), primarilycyclophosphamide (CP), ifosfamide (IF), methotrexate (MTX), 5-fluorouracil (5FU), cisplatin(Pt), paclitaxel (Pac), vinca alkaloids and anthracyclines. These substances are among the most frequently used and the most important from a toxicological point of view. In addition, they are commercially available as analytical standard products.

Any choice of marker cytotoxic drugs should be based on a thorough knowledge of hospital activities and specialties. For example, hospitals carrying out the Heated Intraperitoneal Perioperative Chemotherapy Procedure (HIPEC) should evaluate environmental contamination for platinum derivatives [START_REF] Konate | Evaluation of environmental contamination by platinum and exposure risks for healthcare workers during a heated intraperitoneal perioperative chemotherapy (HIPEC) procedure[END_REF].

Environmental sampling dosing methods

The range of drugs monitored depends on currently available analytical techniques. High performance liquid chromatographytandem mass spectrometry (LC/MS/MS) can be used to monitor a wide variety of drugs via previously described multi-compound techniques. Inductively coupled plasma mass spectrometry (ICP-MS)

or voltammetry can be used for environmental monitoring of platinum salts. High performance liquid chromatography -UV detection (LC-UV) imposes a choice of marker cytotoxic drugs, such as CP [START_REF] Siderov | Reducing workplace cytotoxic surface contamination using a closed-system drug transfer device[END_REF] or 5FU [START_REF] Tkaczuk | Surface contamination of cytotoxic drug 5fluorouracil (5-FU) and decontamination[END_REF][START_REF] Lee | Surface Contamination from Cytotoxic Chemotherapy Following Preparation and Administration[END_REF]). Gaz chromatographymass spectrometry (GC/MS) was also used for the environmental monitoring of CP, IF and 5FU [START_REF] Sessink | Occupational exposure to antineoplastic agents at several departments in a hospital. Environmental contamination and excretion of cyclophosphamide and ifosfamide in urine of exposed workers[END_REF][START_REF] Castiglia | Evaluation of occupational exposure to antiblastic drugs in an Italian hospital oncological department[END_REF][START_REF] Kosjek | Fluorouracil in the environment: analysis, occurrence, degradation and transformation[END_REF].

Wipe sampling method and extraction

In several investigations, wipe sampling was performed on different surfaces and objects. Thiswas the most common practice to monitor residual contamination in reconstitution and care areas, administrative units, equipment, and to test the effectiveness of decontamination techniques [START_REF] Sottani | Simultaneous determination of gemcitabine, taxol, cyclophosphamide and ifosfamide in wipe samples by high-performance liquid chromatography/tandem mass spectrometry: protocol of validation and uncertainty of measurement[END_REF]. A variety of materials,of sampling areas, of types of solution and volumes of desorption solution were addressed. Major wipe sampling and extraction methods are detailed in Table 2.

Cytotoxic exposure should be as low as possible. Environmental samples often need to be concentrated to increase sensitivity, in particular when samples are analyzed by LC-UV. In contrast, the sensitivity of LC/MS/MS means that preconcentration is not always necessary [START_REF] Sabatini | A new high-performance liquid chromatographic/ electrospray ionization tandem mass spectrometric method for the simultaneous determination of cyclophosphamide, methotrexate and 5-fluorouracil as markers of surface contamination for occupational exposure monitoring[END_REF].

Sample concentration should be performed by solid phase extraction (SPE) or liquid-liquid extraction (LLE). SPE is often described as faster than LLE, but also more expensive and it does not always allow to increase the Limit of Detection (LOD) and the Lowest Limit of Quantitation (LLQ) (Juhascik and Fenkins 2009).

Several methods of environmental sample extraction were described and compared (Table 2). When analyzed by LC-UV, 5FU always needs to be concentrated by LLE or SPE. 5FU is very difficult to extract byreverse phase (RP)SPE because it is an extremely polar weak acid [START_REF] Kosjek | Fluorouracil in the environment: analysis, occurrence, degradation and transformation[END_REF]).5FU extraction yields were evaluated for several SPE columns, with highly varying recovery results, from 0.2% to more than 90%.Isolute ® ENV+ SPE appears to be the most suitable column, [START_REF] Micoli | Determination of 5-fluorouracil in environmental samples by solid-phase extraction and high-performance liquid chromatography with ultraviolet detection[END_REF][START_REF] Kosjek | Fluorouracil in the environment: analysis, occurrence, degradation and transformation[END_REF]providing effective extraction regardless of both 5FU concentration and applied volume [START_REF] Micoli | Determination of 5-fluorouracil in environmental samples by solid-phase extraction and high-performance liquid chromatography with ultraviolet detection[END_REF].

LC-UV sensitivity appears to be inadequate for environmental monitoring of CP without preconcentration. A sufficiently sensitive method, for example with SPE as in biological sample treatment (Baumann and Freiss 2001),needs to be developed.Currently, samples can be analyzed with either LC/MS/MS or Gas chromatography -mass spectrometry (GC/MS). Six different types of wipe tissue were evaluated for their recovery potential: Easi-Tex Master  Plus, Care Facial  tissues, nonwoven swabs, sterile compresses, Kimcare  medical wipes and Swedish filter papers [START_REF] Hedmer | Development and validation of methods for environmental monitoring of cyclophosphamide in workplaces[END_REF]). Nonwoven swabs had the best and the highest CP absorption capacity. Size of sampling area was also evaluated (100 or 400 cm 2 ) and a large sample area was generally preferable.

SPE should be avoided for Pac because the vehicle formulation (Cremophor EL  ) can affect the effectiveness of the extraction technique. Instead of SPE, LLE with ethyl acetate can be used [START_REF] Sottani | Simultaneous determination of gemcitabine, taxol, cyclophosphamide and ifosfamide in wipe samples by high-performance liquid chromatography/tandem mass spectrometry: protocol of validation and uncertainty of measurement[END_REF]).For MTX, however, SPE is necessary with LC-UV analysis and withLC/MS/MS for smaller areas, such as gloves. LLE is not recommended because of the low aqueous solubility of MTX [START_REF] Turci | Determination of methotrexate in environmental samples by solid phase extraction and high performance liquid chromatography: ultraviolet or tandem mass spectrometry detection?[END_REF].

For platinum environmental monitoring [START_REF] Brouwers | Monitoring of platinum surface contamination in seven Dutch hospital pharmacies using inductively coupled plasma mass spectrometry[END_REF]), wipe materials (Kimtech ® wipes, Whatman ® filters and Klinion ® gauzes) were evaluated for platinum contamination and for their ability to release platinum from stainless steel surfaces.Wipe solvents (water, 1% HCl, 80% ethanol) and desorption solvents (1% HNO 3 , 5% HNO 3 , 1% HCl) were also evaluated. Best experimental conditions were reported (Entry 7).

More generally, the variability of cytotoxic drugs' recovery (Gem, Pac, CP and IF) has been demonstrated to be more than 20% according to surface type (for example, stainless steel hood work tray, linoleum flooring, laminated bench top) [START_REF] Sottani | Simultaneous determination of gemcitabine, taxol, cyclophosphamide and ifosfamide in wipe samples by high-performance liquid chromatography/tandem mass spectrometry: protocol of validation and uncertainty of measurement[END_REF].

Recently developed multi-compound methods allow quantification by LC/MS/MS of a set of 10 cytotoxicdrugs simultaneously. Initially, this elegant method involved wipe sampling with blotting paper (Whatman 903 ® ) followed by ultrasonic desorptionfrom the paper with water/formic acid (0.1%) [START_REF] Nussbaumer | Simultaneous quantification of ten cytotoxic drugs by a validated LC-ESI-MS/MS method[END_REF]. The major limitation of this method was the wide variation in percentagerecovered among the 10 cytotoxic drugs, from 18±12% (VCR) to 94±10% (Cyt). High standard deviations were also reported, for example 34±18% for Iri. Several modifications were consequently realized to improve this technique and extraction procedure [START_REF] Nussbaumer | Wipe sampling procedure coupled to LC-MS/MS analysis for the simultaneous determination of 10 cytotoxic drugs on different surfaces[END_REF].First, 20% acetonitrile (ACN) was added to the desorption solution, thereby increasing the hydrophobic substancesrecovery, and a centrifugation step was added. Then, several filter papers (Whatman ® , Ahlstrom ® , Texwipe ® ) were compared, and theWhatman ® filter paper was best for environmental monitoring. Finally, recoveries were assessed on a wide variety of surfaces (stainless steel, polypropylene, polystyrol, glass, latex, computer mouse, paperboard) for each cytotoxic, enabling to determine a correction factor per compound and per surface.

LLQs and LODs of environmental analysis GC/MS, LC-UV or LC/MS/MS are the most frequently analytical techniques used for cytotoxic analysis [START_REF] Sottani | Simultaneous determination of gemcitabine, taxol, cyclophosphamide and ifosfamide in wipe samples by high-performance liquid chromatography/tandem mass spectrometry: protocol of validation and uncertainty of measurement[END_REF]. LLQ is often defined as the lowest concentration level with between-day relative error and precision less than or equal to 20% and LOD is the concentration giving signal intensity at least equal to three times the background value [START_REF] Micoli | Determination of 5-fluorouracil in environmental samples by solid-phase extraction and high-performance liquid chromatography with ultraviolet detection[END_REF]. LLQ and LOD of several techniques are presented in Table 3. Moreover, these methods were validated with determination of linearity and accuracy in most of the cases.

There is not yet any standardization of units of measurement for LOD and LLQ determination. Authors use ng/mL(sample concentration) or ng/cm 2 (surface of the area sampled), or ng (per sample). Where possible, the units described by authors were harmonized here, in order to facilitate comparison. We believe that expressing LOD, LLQ and surface contamination results in ng/cm 2 should be standardized,facilitating comparison of results from different studies, this unit of measurement is also more readily comprehensible to clinicians. When compared with LC/MS/MS, LC-UV analytical techniques for environmental monitoring suffer from a lack of sensitivity, but also from a lower specificity. In particular for environmental samples,because of the presence of many agents on the working surface, LC/MS/MS remains the gold standard.

Laboratories equipped with an LC/MS/MS should use multi-compound methods for environmental monitoring (Nussbaumer et al. 2000;Nussbaumer et al. 2002;[START_REF] Connor | Evaluation of Antineoplastic Drug Exposure of Health Care Workers at Three University-Based US Cancer Centers[END_REF][START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF]). If the investment appears too high, mono-compound analyses by LC-UV can be alternately worked out. As these methods are time-consuming and the LLQsare higher, the cytotoxic assessed must be chosen carefully.GC/MS and GC/MS/MS were mainly described for the monitoring of CP and IF [START_REF] Sessink | Occupational exposure to antineoplastic agents at several departments in a hospital. Environmental contamination and excretion of cyclophosphamide and ifosfamide in urine of exposed workers[END_REF][START_REF] Castiglia | Evaluation of occupational exposure to antiblastic drugs in an Italian hospital oncological department[END_REF], involving a derivatization step using fluorinated anhydrides. GC/MS/MS can also be used for 5FU monitoring, after a derivatization step by silylation with MTBSTFA (N-methyl-N-[tertbutyldimethylsilyl]trifluoroacetamide), described as the better reagent for 5FU [START_REF] Kosjek | Fluorouracil in the environment: analysis, occurrence, degradation and transformation[END_REF]. Currently, there are no standardsfor environmental exposure to cytotoxics. USP ˂797˃ recently stated that more than 1ng/cm 2 of CP was found to cause human uptake. MEWIP, a large-scale investigation, led to a cytotoxicindependent target value of 0.1 ng/cm 2 , based on the 90 th percentile of the results [START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF].

CP, MTX and 5FU were the main cytotoxic drugs chosen for environmental monitoring from the 1990s by LC-UV [START_REF] Sessink | Occupational exposure to antineoplastic agents at several departments in a hospital. Environmental contamination and excretion of cyclophosphamide and ifosfamide in urine of exposed workers[END_REF], and currently by LC/MS/MS. MTX went from an LOD of 0.4 ng/cm 2 to an LLQ of 3.7 10 -3 ng/cm 2 , 5FU from an LOD of 0.04 ng/cm 2 to an LLQ of 11 10 -3 ng/cm 2 , and CP from an LOD of 3 ng/cm 2 toan LLQ of 3.7 10 -3 ng/cm 2 [START_REF] Sessink | Occupational exposure to antineoplastic agents at several departments in a hospital. Environmental contamination and excretion of cyclophosphamide and ifosfamide in urine of exposed workers[END_REF][START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF]).In the absence of any consensus, but when compared with the USP values for CP and the MEWIP project target values, the LODs of the methods using LC-UV for MTX and CP do not appear to be sufficient for environmental monitoring. However, the LOD of 5FU evaluated by LC-UV (from 0.04 ng/cm 2 to 0.1 ng/cm 2 )may be low enough for effective monitoring. The assessment of Pacenvironmental monitoring with LC/MS/MS methods alone was assessed [START_REF] Sottani | Simultaneous determination of gemcitabine, taxol, cyclophosphamide and ifosfamide in wipe samples by high-performance liquid chromatography/tandem mass spectrometry: protocol of validation and uncertainty of measurement[END_REF][START_REF] Sottani | Rapid and sensitive determination of paclitaxel (Taxol) in environmental samples by high-performance liquid chromatography tandem mass spectrometry[END_REF][START_REF] Connor | Evaluation of Antineoplastic Drug Exposure of Health Care Workers at Three University-Based US Cancer Centers[END_REF][START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF], led to LLQs ranging from 18.10 -3 to 125.10 -3 ng/cm 2 ,depending on the protocol.Nevertheless,it should be possible to develop LC-UV Pac monitoring using protocols described for biological samples, even though the detection limit will be higher [START_REF] Huizing | High-performance liquid chromatographic procedures for the quantitative determination of paclitaxel (Taxol) in human urine[END_REF].

Platinum derivative environmental monitoring with both ICP-MS and voltammetrywas assessed, with similar LODs and LLQs [START_REF] Brouwers | Monitoring of platinum surface contamination in seven Dutch hospital pharmacies using inductively coupled plasma mass spectrometry[END_REF][START_REF] Schmaus | Monitoring surface contamination by antineoplastic drugs using gas chromatography-mass spectrometry and voltammetry[END_REF][START_REF] Ensslin | Urinary platinum in hospital personnel occupationally exposed to platinum-containing antineoplastic drugs[END_REF]. As voltammetry appears to be less expensive than ICP-MS, it should be the preferred platinum environmental monitoring method.

Besides these traditional analytical techniques, the current development of a 5FU monitor, able to detect cytotoxic surface contamination in near real time, appears very promising, with LODs ranging from 0.1 to 0.25 ng/cm 2 (Smith et al. 2015).

Applications and discussion

Several procedures for cytotoxic drug environmental evaluation were applied in preparation and administrationunits. Results for selected cytotoxics are summarizedin Table 4. Severalstudies [START_REF] Connor | Surface contamination of chemotherapy drug vials and evaluation of new vial-cleaning techniques: results of three studies[END_REF][START_REF] Favier | External contamination of vials containing cytotoxic agents supplied by pharmaceutical manufacturers[END_REF][START_REF] Fleury-Souverain | Determination of the external contamination and cross-contamination by cytotoxic drugs on the surfaces of vials available on the Swiss market[END_REF][START_REF] Gilbar | External contamination of cytotoxic drug vials[END_REF][START_REF] Naito | Comparison of contamination levels on the exterior surfaces of vials containing platinum anticancer drugs in Japan[END_REF][START_REF] Nygren | Cisplatin contamination observed on the outside of drug vials[END_REF]described surface contamination ofmarketed cytotoxic drug vials, with a possibility of cross-contamination by cytotoxic drugs. No Food and Drug Administration (FDA)requirements exist regarding cleanliness of bottle external surfaces. However, contamination may be reduced by using a decontamination device [START_REF] Touzin | Cyclophosphamide contamination observed on the external surfaces of drug vials and the efficacy of cleaning on vial contamination[END_REF]) and protective sleeves [START_REF] Schierl | Surface contamination of antineoplastic drug vials: comparison of unprotected and protected vials[END_REF]) during manufacturing.

Furthermore, cytotoxic drug contamination of marketed vials could be evaluated and taken into account in the hospital tender procedure.

A clear improvement in protection for workers handling cytotoxics has been made in recent years.

Where simple laminar flow hoods [START_REF] Mason | Exposure to antineoplastic drugs in two UK hospital pharmacy units[END_REF] were used in the past, today, they often have been replaced by pressure isolators. In units where isolators are used, while contaminants were often found inside isolators, only a few traces were found outside [START_REF] Kopp | Environmental and biological monitoring of platinum-containing drugs in two hospital pharmacies using positive air pressure isolators[END_REF][START_REF] Crauste-Manciet | Environmental contamination with cytotoxic drugs in healthcare using positive air pressure isolators[END_REF]. Isolators' effectiveness mainly depends on operators' work practices, and contamination from the pass-through could be reduced by surface decontamination. Several studies also demonstrated the efficacy of closed-system drug transfer device (CSTDs) [START_REF] Wick | Using a closed-system protective device to reduce personnel exposure to antineoplastic agents[END_REF][START_REF] Connor | Effectiveness of a closed-system device in containing surface contamination with cyclophosphamide and ifosfamide in an i.v. admixture area[END_REF], which can reduce contamination by95% [START_REF] Sessink | Reduction in surface contamination with antineoplastic drugs in 22 hospital pharmacies in the US following implementation of a closed-system drug transfer device[END_REF]. Robot assisted preparationswere also developed to reduce residual contamination from 70% under classic preparation conditions to 15% with the Apoteca  chemo system [START_REF] Schierl | Environmental contamination by cyclophosphamide preparation: Comparison of conventional manual production in biological safety cabinet and robot-assisted production by APOTECAchemo[END_REF].

Similarly, the CytoCare  chemotherapy compounding robot allowed preparation of CP with low environmental contamination levels and no measurable exposure of technicians [START_REF] Sessink | Environmental contamination, product contamination and workers exposure using a robotic system for antineoplastic drug preparation[END_REF].

However, despite subsequentrecommendations and solutions to environmental monitoring, contamination cannotcurrently be totally eliminatedandoccupational exposurescan occur. Adverse effects on workers handling cytotoxic agents were describedsuch as hair loss, rash [START_REF] Valanis | Association of antineoplastic drug handling with acute adverse effects in pharmacy personnel[END_REF][START_REF] Krstey | Work practice and some adverse health effects in nurses handling antineoplastic drugs[END_REF] and delayed effects on reproduction [START_REF] Stücker | Relationship between birthweight and occupational exposure to cytostatic drugs during or before pregnancy[END_REF][START_REF] Valanis | Occupational exposure to antineoplastic agents: self-reported miscarriages and stillbirths among nurses and pharmacists[END_REF]Fransman et al. 2007). Some antineoplastic drugs are genotoxic [START_REF] Rombaldi | Occupational risk assessment of genotoxicity and oxidative stress in workers handling anti-neoplastic drugs during a working week[END_REF][START_REF] Cavallo | Evaluation of genotoxic effects induced by exposure to antineoplastic drugs in lymphocytes and exfoliated buccal cells of oncology nurses and pharmacy employees[END_REF] and are known to cause or suspected of causing cancerous pathologies [START_REF] Connor | Hazardous anticancer drugs in health care: environmental exposure assessment[END_REF]; International Agency for Research on Cancer 2016).

Therefore, several environmental monitoring studies involved biological assessment ofcytotoxic excretion in healthcare-professionals [START_REF] Turci | Biological and environmental monitoring of hospital personnel exposed to antineoplastic agents: a review of analytical methods[END_REF][START_REF] Pethran | Uptake of antineoplastic agents in pharmacy and hospital personnel. Part I: monitoring of urinary concentrations[END_REF][START_REF] Schreiber | Uptake of antineoplastic agents in pharmacy personnel. Part II study of work-related risk factors[END_REF][START_REF] Sottani | An analysis to study trends in occupational exposure to antineoplastic drugs among health care workers[END_REF].

Analysis of chromosomal effects on the DNA of workers exposed to cytotoxic drugs by fluorescent in situ hybridization (FISH) was conducted, seeking the"signature"lesions found in patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) [START_REF] Mcdiarmid | Chromosomal effects of non-alkylating drug exposure in oncology personnel[END_REF]. A dose-related increase wasdetected, showing that significant biological exposure to genotoxic drugs occurs in oncology workplaces.

Environmental monitoring of cytotoxic drugs should follow two main principles. In order to analyze the exposure of healthcare workers and the safety of the -preparation to administration‖ process, it is necessary to realize a wide variety of sampling points, including surfaces and objects. On the other hand, to evaluate the impact of monitoring on contamination level,the number of sampling points should be standardized.

Larger studies described contamination occurring in hospitals and/or in community pharmacies (Schierl et al. 2006;[START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF]),but environmental monitoring can also be performed in care areas [START_REF] Connor | Evaluation of Antineoplastic Drug Exposure of Health Care Workers at Three University-Based US Cancer Centers[END_REF] or at every step of the cytotoxic drug circuit.For example, secondary exposure of family members to cytotoxic drugs via excreta of the treated cancer patient was recently described for CP. Levels of 0.03-7.34 ng/cm 2 were found in patients' home, and cytotoxic drugs werealso found in urine samples of family members (Yuki et al. 2013;Yuki et al. 2015). Exposure to cytotoxic drugs outside the hospital environment could also concern the pharmaceutical industry, universities, pharmacies, veterinary practices, laundry facilities and waste treatment [START_REF] Meijster | Exposure to antineoplastic drugs outside the hospital environment[END_REF].For example, patients' bed sheets appeared to be contaminated with detectable levels of cytotoxics (0.13-30.6 ng/cm 2 ) before the washing procedure in an industrial laundry facility (Fransman et al. 2007).

Several studies demonstrated the value of regular environmental monitoring. The MEWIP Project aimed to collect informations about the mechanisms and the release/propagation pathways of cytotoxic drugs [START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF] Current knowledge is too limited to set a no-health-effect levelfor cytotoxic drug exposure [START_REF] Schierl | Guidance Values for Surfaces Monitoring of Antineoplasic Drugs in German Pharmacies[END_REF],and a zero level of exposure is not likely to be achievable in workplaces [START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF]).However, as analytical techniques evolve, LLQs decrease and the number of positive samples increases, even though mean contamination levelshave beenreduced.In 2009 [START_REF] Schierl | Guidance Values for Surfaces Monitoring of Antineoplasic Drugs in German Pharmacies[END_REF]) and 2013 [START_REF] Kiffmeyer | Application and Assessment of a Regular Environmental Monitoring of the Antineoplastic Drug Contamination Level in Pharmacies -The MEWIP Project[END_REF],two large studies established from more than 1,200 wipe samplings and more than 100 hospitals or community pharmacies, a mean level of contamination by 5FU and other cytotoxic drugs. For 5FU, although the number of positive samples varied from 31% (LLQ 5FU = 11 pg.cm -2 ) to 74.4% (LLQ 5FU = 0.75 pg.cm -2 ), the 75 th and 90 th percentile from these studies were similar(90 th percentile = 0.117 and 0.251 ng/cm 2 , 75 th percentile = 0.016 and 0.029 ng/cm 2 ). The first study suggested technical guidance values based on the 50 th (5.10 -3 ng/cm 2 ) and the 75 th percentile (0.03 ng/cm 2 ) [START_REF] Schierl | Guidance Values for Surfaces Monitoring of Antineoplasic Drugs in German Pharmacies[END_REF]).The second study recommended less strict technical guidance values, based on the 90 th percentile (0.1 ng/cm 2 ).This guidance value is the same for all 8 cytotoxic drugs tested in the study. This recommendation is based on two factors: the urgent need to improve the situation in workplaces with high levels of contamination, and the possibility that the 75 th percentile of most substances will fall below the LLQ. Furthermore, this technical guidance value of 0.1 ng/cm 2 , applied to CP, is tenfold lower than the USP ˂797˃ value (a content higher than 1 ng/cm 2 ofCP was found to cause human uptake).These guidance values were established for pharmacies, asthere are fewer studies conducted in hospital wards. From our knowledge, only one large study [START_REF] Hedmer | Hygienic guidance values for wipe sampling of antineoplasic drugs in Swedish hospitals[END_REF]) conducted in 17 workplaces from 6 hospitals allowed the authors to determine guidance values for hospital wards for CP and IF. In this study, the authors emphasized on the heterogeneity of contamination among the different categories of tested surfaces. The suggested guidance values were established from the 90 th percentile, for each sort of surface.

Conclusion

The reliability of detection techniques is constantly improving. Multi-compound analyses allow fast and economical environmental monitoring. However, theconstant decrease in detection limits inevitably leads to anincrease in positive samples. Without toxicological studies establishing a correlation between exposure values and health impact on healthcare workers, -as low as reasonably achievable‖ levels remain the gold standard.

The studies reviewed here underline the need to keep striving to better protect workers, at the same timerevealingseveral working procedure problems. Environmental monitoring is a useful tool not only for local contamination evaluation, but also to evaluate technologies involved in the cytotoxic drug circuit.Recommended dosing techniques should be used routinely in every place where cytotoxic exposure is suspected. Good practice recommendations need to include environmental monitoring from the industrial process to the patient's home, with a special focus on hospital pharmacies and care areas. Real awareness has emerged inseveral countries regarding the overall management of cytotoxics, but international or at least national recommendations for environmental contamination monitoring are needed.

Table 1 :

 1 Classification of anticancer drugs according to IARC monographs

	Cytotoxicchemotherapeutic agents	Groups	Group definition
	CP, etoposide	Group 1	Carcinogenic to humans
	Pt, Dox, daunorubicine	Group 2A	Probablycarcinogenic to humans
	Bleomycin, dacarbazine	Group 2B	Possibly carcinogenic to humans
	IF, 5FU, MTX, vincristine, vinblastine	Group 3	Not classifiable as carcinogenic to humans
	Pac, Doc, Top, Iri, Epi, Cyt, Gem	--	Actually not classified in IARC monographs
	CP: cyclophosphamide; Pt: cisplatin; Dox: doxorubicin; IF: ifosfamide; 5FU: 5-fluorouracil; MTX: methotrexate; Pac: paclitaxel; Doc:
	docetaxel; Top: topotecan; Iri: irinotecan; Epi: epirubicin; Cyt: cytarabine; Gem: gemcitabine.

Table 2 :

 2 Sampling and extraction techniques for cytotoxic drugs environmental monitoring.

	Drug quantified (Reference)	Sampling technique	Extraction technique	Extraction yields
	Pac (Sottani et al. 2000)		Cotton / methanol	LLE (water pH 7.0/ethyl acetate)	> 90%
	5FU (Gilles et al. 2009)		Filter paper (Whatman ® )	LLE (water/ethylacetate/isopropanol)	71%
	5FU (Micoli et al. 2001)		Cotton / acetate buffer (pH 4.7)	SPE Isolute ® ENV+ columns (200 mg/6 mL) Mean = 94.1%
	5FU (Kosjek et al. 2013)	100 mL water samples	SPE Isolute ® ENV+ columns (500 mg/6 mL) Wastewater = 53 ± 28%
							Surface water = 93 ± 2%
	MTX (Turci et al. 2000)		Cotton		SPE Isolute® C18 (500 mg/10 mL)	Mean = 78.4%
	CP (Hedmer et al. 2004)		Nonwoven swab /NaOH 0.03M LLE (water/ethyl acetate)	> 78%
	Pt (Brouwers et al. 2007)	Kimtech ® Science precision	Ultrasonic desorption (1% HCl) and	50.4% to 81.4%
					wipes / water		filtration
	5FU, CP, MTX (Sabatini et	Kleenex ® / ammonium acetate	none	5FU MTX: ≈ 78%
	al. 2005)			solution (pH 6.9)	CP: 100%
	5FU, IF, CP (Castiglia et al.	TNT gauzes / NaOH 0.03M	Ultrasonicdesorption,	SPE	NR
	2008)						diatomaceousearth (elutiondiethylether)
	CP, IF, Pac, Gem (Sottani et	Ashless	filter	paper	OASIS ® HLB cartridges (200 mg/ 6 mL)	Gem: 62-81%
	al. 2007)			(Whatman ® ) / water	SPE	Pac: 55-81%
							CP, IF: 63-81%
	CP, Cyt, Dox, Epi, Eto, Gem,	Blotting paper (Whatman ® )	Ultrasonic desorption (water/formic acid)	From 20% (VCR) to 89%
	IF,	Iri,	MTX,	VCR			(Cyt) on stainless steel
	(Nussbaumer et al. 2010)			surfaces.
	CP, Cyt, Dox, Epi, Eto, Gem,	Filter paper (Whatman ® )	Ultrasonic desorption (water/ACN/formic	From 45% (Eto) to 86% (CP)
	IF,	Iri,	MTX,	VCR			acid) and centrifugation	on stainless steel surfaces
	(Nussbaumer et al. 2012)
	CP: cyclophosphamide; Pt: cisplatin; Dox: doxorubicin; IF: ifosfamide; 5FU: 5-fluorouracil; MTX: methotrexate; Pac: paclitaxel; Doc:
	docetaxel; Top: topotecan; Iri: irinotecan; Epi: epirubicin; Cyt: cytarabine; Gem: gemcitabine; VCR: vincristine; SPE: solid phase extraction;
	LLE: liquid-liquid extraction.

Table 3 :

 3 LLQs and LODs of analytical techniques for environmental monitoring

	Reference	Analytes	Technique	LOD	LLQ	LOD	LLQ	LOD	LLQ
				(ng/mL)	(ng/mL)	(ng/cm 2 )	(ng/cm 2 )	(ng/sample)	(ng/samp
									le)
	Huizing et al. 1995 p	Pac n	LC-UV		SPE: 10
					LLE: 250
	Sotani et al. 2007	Pac	LC/MS/MS						10
	Sessink et al. 1992 o	MTX	LC-UV	60		0.4 -1		3 -6
	Turci et al. 2000	MTX	LC-UV						150
	Turci et al. 2000	MTX	LC/MS/MS						5
	Micoli et al. 2001	5FU	LC-UV					50	150
	Gilles et al. 2009	5FU	LC-UV	5	15
	Sessink et al. 1992 o	5FU	LC-UV	7		0.04 -0.1		0.3 -0.7
	Kosjek et al. 2013	5FU	GC/MS/MS	0.16-0.48	0.54-1.6 10 -3
				10 -3
	Hedmer et al. 2004	CP	LC/MS/MS			0.05 10 -3		0.02
	McDevitt et al. 1993 o	CP	LC-UV			3-25
	Sessink et al. 1992 o	CP	GC/MS	0.1		0.01-0.02		0.06 -0.1
	Minoia et al. 1998 p	CP, IF	LC/MS/MS			0.01		20
	Castiglia et al. 2008	3 a,b,d	GC/MS/MS a,d			0.12, a 0.6, d
			LC-UV b

Table 4 :

 4 Environmental monitoring of selected cytotoxicsin preparation and administrationunits.

	Reference	Place monitored	number of sample	Positive samples		Results
					Cytotoxic: 5FU
	Micoli et al. 2001	4	preparation/	61	49%			Inside hood = 715 ng/cm 2
		administration					Floor in front of the hood = 12 -1461ng/cm 2
		units						Top of hood = 80 -2110ng/cm 2 Internal surface of gloves =
								70 -3770 ng (preparation)120 -3290 ng (administration)
	Connor et al. 2010 3 hospitals	143	26%			Pharmacies, mean values = 0.13-0.53 ng/cm 2
		(7 pharmacies, 10					Nursing/patient areas, mean values = ˂ 0.06-35.44 ng/cm 2
		nursing/patient
		areas)
	Schierl et al. 2009	102 pharmacies	1237	74.4%			10 sampling sites.
								90 th percentile = 0.251 ng/cm 2 75 th percentile = 0.029 ng/cm 2
	Kiffmeyer et al.	130 pharmacies	1269	31%			3 sampling sites: Floor, work top and refrigerator door.
	2013							90 th percentile = 0.117 ng/cm 2 75 th percentile = 0.016 ng/cm 2
								Highest values = Work top, 24 ng/cm 2
					Cytotoxic: CP
	Connor et al. 2010 3 hospitals	143	43%			Pharmacies, mean values = 0.47-16.00 ng/cm 2
		(7 pharmacies, 10					Nursing/patient areas, mean values = 0.01-0.12 ng/cm 2
		nursing/patient
		areas)
	Bussières et al.	25 hospitals	259	52%:	50%	in	Highest values = Exterior surface of hazardous drug container,
	2012				pharmacies, 54% in	28 ng/cm 2
					patient care areas		Median = 0.0035 ng/cm 2
	Hedmer et al.	6 hospitals (17	447	80%: 95% on floors,	Highest values = Floors in the patient lavatories, median = 1.1
	2012	outpatient		65% on work areas	ng/cm 2

  . To study the impact of monitoring, 130 pharmacies were randomized into two groups.Environmental monitoring in group A was regular throughout the study period, but occurred only at the beginning and at the end of the project in group B. Using a validatedmulticompound technique[START_REF] Tuerk | Development and validation of an LC-MS/MS procedure for environmental monitoring of eight cytostatic drugs in pharmacies[END_REF],eight cytotoxics were quantified, a sample being considered positive if at least one of the drugs was detected. Contamination levels were constantly decreasing in group Apharmacies, where, after the first report of results, cleaning protocols, gloves, equipment modifications and more intensive training of cytotoxic drugs' handlerwere implemented. Thus, it appears that repeated monitoring has a greater effect on level of contamination than a single campaign.Another multicenter study was performed after publication of a prevention guide recommending annual monitoring and the development of an environmental monitoring program[START_REF] Bussières | Environmental Contamination with Hazardous Drugs in Quebec Hospitals[END_REF].Every hospital included had at least one sample with a positive result for at least one cytotoxic (CP, IF or MTX). Once again, periodic monitoring of surface contamination was shown to ensure updating of practices for better worker protection.