Cancer chemotherapy is a relatively recent development in medical history.
Cancer chemotherapy is a relatively recent development in medical history. Dating to chemical warfare with mustard gas, the modern use of cytotoxic drugs dates to within the lifetime of many cancer researchers. Chemotherapy nurses in human medicine are monitored for exposure to chemotherapy drugs as chronic exposure can create a risk to the health care provider for DNA damage, leukemias and other cancers, as well as other health risks, probably not fully understood. In veterinary medicine, there is a lack of standardized recommendations and monitoring for those technicians, clinicians, and pharmacists involved in regular chemotherapy administration to animals with cancer. Additionally, most practices are not equipped with safety equipment that is routine in human hospitals. Therefore, standards of chemotherapy handling are needed.
In 2008, the Veterinary Cooperative Oncology Group voted to develop a consensus document addressing this need. Guidelines exist for the European Society of Veterinary Oncology as well as human medicine, and these have formed the basis for this document. Consensus generation is ongoing and current status will be discussed at this talk, though specifics are not available at the time of this writing.
Chemotherapy can be detected in feces and urine for up to several days following chemotherapy with some drugs. Platinum drugs are primarily renally excreted so pet owners and veterinary personnel should avoid contact with treated pet's urine for at least 72 hours following treatment. Many drugs excreted primarily in bile are inactivated in the feces as they come in contact with organic matter, so feces are less of a concern for exposure, though still should be handled with care. No information is available regarding drug residues in saliva so close contact with the oral cavity of the treated animal (such as allowing licking of the owner's face or hands) should be avoided for 3 days if possible.
Newer devices have been developed to minimize exposure to chemotherapy agents. The Phaseal® system was developed as a closed system such that environmental exposure to drug is all but eliminated. Though this adds cost to each treatment, the benefit of safe handling is worth the added expense and should be factored in to the cost of chemotherapy. This system is not a substitute for other measures, but can significantly decrease the risk of exposure. If possible, a biosafety cabinet should be used. Table-top models can be purchased for practices involved in high-volume chemotherapy, whether specialty or general practice. Most academic and larger institutions maintain a full biosafety hood. In addition to this, hands and mucous membranes should be covered. This means latex or nitrile, powder-free gloves, goggles or glasses, and ideally a mask. Food should never be consumed in an area where chemotherapy is administered to decrease the risk of consumption of aerosolized chemotherapy. Finally, a disposable gown should be worn when preparing and administering chemotherapy to eliminate chemotherapy droplets from adsorbing onto clothing fibers.
Though it may seem intuitive, it is important to emphasize to owners that oral chemotherapy drugs should always be handled with latex or nitrile, powder-free gloves. Alyklating agents are commonly given in the oral setting and can cause mutations in stem cells, leading to leukemia. These drugs are often administered chronically (as with oral chlorambucil for chronic lymphocytic leukemia) representing a significant exposure risk to the owners. It is easy for an owner to become desensitized over time to the potential risk of drug exposure and therefore important for the veterinarian involved in cancer therapy to regularly emphasize the measures the owner should be taking.
Any chemotherapy waste, including chemotherapy administration waste, residual chemotherapy (mostly empty bottles) waste, and any other remains should be properly disposed of. Prior to incorporation of chemotherapy into regular practice, consultation with the biohazard waste handler (the service that removes sharps containers from the practice) should occur and properly marked bags and bins used to capture any possible chemotherapy waste.
Additional discussion will be included in this talk pursuant to the presentation of preliminary recommendations at the VCOG meeting at the annual Veterinary Cancer Society meeting in mid-October 2009.