Soft Tissue Sarcoma and Exposure to Phenoxyherbicides and Chlorophenols in New Zealand2

Abstract

Phenoxyherbicides, including (2.4,5-trichlorophenoxy) acetic acid (CAS: 93-76-5), have been widely used in New Zealand for over 30 years. In the light of Swedish studies reporting an association between exposure to phenoxyherbicides or chlorophenols and soft tissue sarcoma, a case-control study was undertaken that involved interviewing 82 subjects (cases) with soft tissue sarcoma and 92 controls with other types of cancer. For those potentially exposed to phenoxyherbicides for more than 1 day not in the 5 years before cancer registration, the estimate of relative risk was 1.3, with 90% confidence limits of 0.6–2.5. The comparable relative risk estimate for chlorophenol exposure was 1.5, with 90% confidence limits of 0.5–4.5. The discovery of cases in trichlorophenol manufacturing plants in the United States lended support to the Swedish findings, but further studies are needed to conclude whether human exposure to these chemicals truly increases the risk of soft tissue sarcoma.