Identification of soft tissue sarcoma deaths in cohorts exposed to dioxin and to chlorinated naphthalenes.
Suruda-AJ; Ward-EM; Fingerhut-MA
Epidemiology 1993 Jan; 4(1):14-19
The adequacy of methods for identifying soft tissue sarcoma (STS) cases in cohort mortality studies was assessed. The review involved data contained in the NIOSH registry of subjects potentially exposed to dioxins and data from an ongoing NIOSH study of workers exposed to chlorinated naphthalenes during World War-II (halowax cohort). Three nosologists identified deaths coded for STS according to the International Classification of Disease (ICD) system. Death certificates for the STS deaths and persons who died from cancers of organs in which STS was known to occur were also reviewed. Medical records and tissue blocks or pathology slides for each STS case were requested and reviewed by consulting pathologists to confirm the diagnosis. A total of 119 deaths in the dioxin registry and 360 deaths in the halowax cohort were identified as possibly involving STS. Careful reading of the wording on the death certificates identified 17 deaths from STS. An additional two cases of STS were identified by reviewing medical records. Only nine STS deaths identified on the death certificates were coded to the correct ICD category. Tissue blocks or pathology slides were available for nine STS cases. STS was confirmed in seven. The remaining two specimens were identified as poorly differentiated carcinomas. The authors conclude that nosologic coding rules limit the ability of cohort mortality studies to detect excess deaths from STS. Developing referent rates that are based on histologic classifications like those used in the coding system of the International Classification of Diseases for Oncology of the World Health Organization would provide more accurate determinations of the incidence of STS.
NIOSH-Author; Epidemiology; Mortality-data; Malignant-neoplasms; Connective-tissue-disorders; Information-systems; Chemical-industry-workers; Histopathology; Chlorinated-hydrocarbons