Antineoplastic drugs: Occupational exposure and health risks

Abstract

Antineoplastic drugs are pharmaceuticals commonly used to treat cancer (and some non-neoplastic diseases), which are generally referred to as 'chemotherapy'. Oncology nurses are exposed to these drugs via the skin of hands during daily nursing activities, even when protective gloves are being used. Results of tests on bulk and surface contamination samples confirmed that patients intravenously treated with cyclophosphamide excrete the unmetabolized drug. The introduction of new guidelines and regulations on working with antineoplastic drugs, the use of more closed preparation- and infusion-systems and the consequent growing awareness of nurses working with antineoplastic drugs has decreased exposure to antineoplastic drugs considerably. Due to an increase in number of chemotherapy treatments and centralisation of chemotherapy to specialised departments in hospitals, the average weekly exposure level of an oncology nurse has not markedly changed over time, while low and high exposures occur less frequent. The identification of the patient as a source of contamination and exposure makes it very complicated to further reduce exposure to antineoplastic drugs of nurses. Based on current dermal exposure levels to antineoplastic drugs approximately 50% of the population of oncology nurses have an increased risk of a prolonged time to pregnancy compared with non-exposed nurses, and around 10% of Dutch oncology nurses have an increased risk of a premature delivery and delivering a child with a low birth weight. Other effects on reproduction like spontaneous abortion, stillbirth, gender of offspring, and congenital malformations were not related to exposure to antineoplastic drugs. The risk of non-lymphocytic leukaemia among oncology nurses after being exposed for 40 years to current dermal exposure levels of cyclophosphamide was estimated to be well below the target risk (one extra cancer case per 10 million per year) and the maximum tolerable risk (one extra cancer case per 100,000 per year) in the Netherlands. However, this estimate is for cyclophosphamide only and in a worst-case exposure scenario the estimated leukaemia risk exceeded the target risk, so the cancer risk among oncology nurses exposed to antineoplastic drugs should not be ignored. The identification of occupational exposure to antineoplastic drugs in sectors outside the hospital environment (i.e. veterinary medicine, home care, nursing homes and industrial laundries) showed that the number of workers potentially exposed to antineoplastic drugs is larger than previously estimated. Exposure levels in these sectors can potentially be higher than in the hospital environment, because exposure routes are complex and awareness of the hazard (and therefore use of protective measures) is limited.