Introduction

Chemotherapy is the use of cytotoxic drugs to treat cancers and sometimes immunological diseases. Over the past few years, the use of chemotherapy has increased vastly. Increased use also means increased exposure.

It is very important to remember that the drugs we use in chemotherapy protocols are cytotoxic. Unlike any other pharmacological agents they are designed to ultimately cause cell death: ideally cancer cells in the patient, but with undue care this could also include healthy cells in the patient, handler and others, as the drugs are unable to differentiate. Primarily those who are at risk are those who prepare, administer and handle the drugs. But risks are also posed to those handling the patient and those caring for the patient afterwards.

It is very important that protocols are followed with regard to handling cytotoxic drugs and related waste. Exposure can occur via inhalation, absorption through the skin, ingestion from contaminated items and accidental inoculation. These risks can be minimised as described in Figure 1.

General Safety Precautions

 Women who are trying to conceive, pregnant or breast feeding should not handle cytotoxic drugs at any time. Chemotherapy drugs target cells that are rapidly dividing and therefore pose a huge risk.

 All chemotherapeutic drugs should be stored, prepared and administered in a designated area and access restricted to immediate staff only. This area should be easy to clean.

 There should be a clear procedure and adequate materials (cytotoxic spill kit) for cleaning of any spilled drugs.

Guidelines for Preparation

Drugs should be prepared in a vertical air flow hood (not horizontal)/biological safety cabinet; inside should be a cytotoxic waste disposal bin for sharps and contaminants. If a hood is not available, drugs should be prepared well away from doors, windows and drafts. Drugs should be prepared on a plastic-backed absorbent liner, whether using a fume hood or not. This can be removed and replaced when the cabinet is cleaned or in the case of any leaks or spills. Close at hand should be gauze swabs and alcohol-soaked swabs.

Protective clothing should be worn by all those involved. This includes a disposable full-length non-permeable gown that is long sleeved with cuffs and is closed at the front. Thick non-powdered latex gloves should be worn pulled over the cuffs of the gown. A mask should be worn with a filter to prevent inhalation of any aerosolised drugs; a surgical mask is not acceptable. Goggles should also be worn.

All materials needed should be in the hood before preparing the drug. Use syringes that are fitted with luer locks, which prevent the syringe from separating from the needle. Choose syringes that do not need to be filled more than three quarters full. Syringes need to be clearly labelled. Many chemotherapy agents are now supplied in solutions such that reconstitution of powdered drug is unnecessary. If this is necessary, adding diluent to powdered drug should be accomplished without spilling or aerosolising any product and care should be taken to neutralise pressure in the vials. Chemotherapy pins can be used to prevent pressure building up in vials and accidental aerosolisation. Wrapping the vial and syringe in alcohol-soaked gauze pads during injection and withdrawal of fluid is recommended to absorb any product spilled during reconstitution. Any fluids and lines should be ready and primed before adding any chemotherapy drugs; this reduces the risk of exposure when connecting the drip set to the patient. Drugs can be added to the bag or burette by wrapping the injection port in an alcohol-soaked swab when inserting the needle. After preparation is complete all drugs should be well labelled and placed in a clear sealable plastic bag before transporting to the patient.

Some chemotherapy drugs are prepared for oral administration. Again these drugs should be prepared on a disposable absorbent pad. They should not be crushed or split and latex gloves should be worn and hands washed in soap and water afterwards. If crushing is absolutely necessary, gown, mask and goggles should be worn and the tablets should be prepared in the hood.

All materials should be bagged and disposed of as contaminated waste, clearly marked 'cytotoxic waste'.

Figure 1. Minimising risks of exposure to cytotoxic drugs.

Guidelines for Administration

 Administration should only be done in the restricted designated area, with minimal staff present.

 Only experienced, well trained staff should be involved.

 Most chemotherapy drugs are administered intravenously and some can be very irritant perivascularly. Therefore, they should be administered via a catheter and every care should be taken placing the catheter cleanly, atraumatically without any complications. If this is difficult and the vein 'blows' another vein should be used.

 A luer lock bung should be used once the catheter is in place.

 An alcohol-soaked swab can be placed over the bung when the needle has been inserted to prevent any aerosolisation whilst the drug is being administered.

 Intravenous catheters should be flushed with 0.9% saline not only to check patency before the drug is given, but also afterwards to clear the catheter.

 Gowns, gloves, masks and goggles should be worn.

 Intravenous bags and tubing should be disposed of intact. Disconnecting tubing may lead to exposure to the drug.

 All waste should be discarded in special waste disposal.

Guidelines for Nursing Patients

 Animals that have received chemotherapy should be easily identifiable. Written on their kennels should be a clearly marked card, the drug given and the date it was given should be clearly visible. It should be marked 'BARRIER NURSE' i.e., disposable gloves and protective clothing should be worn when taking care of the patient.

 All waste from the patient (saliva, urine, faeces, vomit) poses a potential risk after the animal has been treated. Disposable bedding can be used in the cage/kennel, latex gloves should be worn when handling any waste and any contaminated areas should be hosed down.

 The kennel should be thoroughly cleaned and then disinfected when the patient leaves.

Guidelines for Owners

 Written information should be available to owners.

 Owners should understand the general hazards of cytotoxic drugs, and how their pet will excrete these drugs for up to 7 days after their treatment in vomit, faeces, saliva and urine.

 Unnecessary direct contact should be avoided if possible during this time, especially with pregnant women, breast-feeding mums and young children.

 Any excreta should be handled using latex gloves (supplied by the practice) and thrown away in a separate waste bag.

 Animals should not be exercised in public areas during this time.

 Owners administering oral drugs should wear latex gloves when handling tablets, keep all drugs in their original packaging out of the reach of children and other pets and any unused drugs brought back to the practice for safe disposal.

Summary

Safely administering chemotherapy is possible in general practice. All involved should be educated and trained in the safe handling of these cytotoxic drugs and safe practices adhered to each and every time.

References

1.  Barlow L. Basic chemotherapy safety and handling. Veterinary Technician 2003; January.

2.  ECVIMCA; Preventing Occupational and Environmental Exposure to Cytotoxic Drugs in Veterinary Medicine. Document of the ECVIMCA (September 2006).

3.  Lana S. Chemotherapy. In: Dobson, JM; Lascelles BDX. eds. BSAVA manual of canine and feline oncology (second edition). Gloucester: BSAVA, 2003; 86-103.