The evaluation of trends in soft tissue sarcoma according to diagnostic criteria and consumption of phenoxy herbicides

The possible association between exposure to phenoxy herbicides and development of soft tissue sarcomas has been studied in both case‐control and cohort studies. In these studies soft tissue sarcoma cases have been identified from either deaths with malignant neoplasms of the connective tissue (ICD‐8 171) as the underlying cause of death, from incident cancer cases with the same topography code, or from incident cases of extraskeletal sarcomas, excluding lympho and reticulosarcomas. The current study shows that the choice of source material has a considerable influence on the registered occurrence of soft tissue sarcomas in a well defined population. In 1978 to 1982 an annual number of 33 deaths from ICD‐8171 was registered in Denmark, whereas the annual number of diagnosed extraskeletal sarcomas was 231. The distribution over histologic types differed between tumours coded to the connective tissue and extraskeletal sarcomas coded to specific organs. Furthermore, during the period 1943 to 1982 the mortality from ICD‐8 171 increased slightly, whereas the incidence from all extraskeletal sarcomas decreased slightly, except for males since 1970. Time trends based on any of the three source materials should, however, be interpreted with caution.