Risk of large-bowel cancer in synthetic fiber manufacture.

In a previous study, the authors found an increased incidence of colorectal cancer among workers in a textile factory producing synthetic fiber. To answer the crucial question of whether the risk is confined to one section of the plant, a case-control study was done. For each of 43 cancers that occurred in the plant between 1965 and 1979, 3 controls were selected at random from company files of 24,270 current and past employees. They were matched for age, date of beginning employment, and duration of employment. Forty-four percent of the cancer patients worked in one of three departments: "extrusion D," "extrusion TM," and "textile," whereas only 21% of the controls worked in one of these departments (P less than 0.005). After 1974, when the peak incidence was observed, 10 of 21 patients had worked in either or both extrusion departments; only 8 of 63 controls had worked in these departments. (P less than 0.002). It took more than 10 years (10 of 33 cases versus 8 of 95 controls; P less than 0.002) before a risk became apparent. According to work areas, the relative risk was increased for those who had worked in building 3, where the extrusion D department was located (P less than 0.02). These results offer a basis for the prevention and surveillance of colorectal cancer in this industry.