Future research needs in the silica, silicosis and cancer field.
Goldsmith-DF; Wagner-GR; Saffiotti-U; Rabovsky-J; Leigh-J
Scand J Work, Environ & Health 1995 Sep; 21(Suppl 2):115-117
The current state of knowledge and future research needs in the area of silica (14808607) dust exposure, silicosis, and cancer were discussed. The discussion emphasized papers presented at the Second International Symposium on Silica, Silicosis, and Cancer held in San Francisco, California in October 1993. Prior to the Symposium, studies in laboratory rats and epidemiological studies had suggested that inhalation of silica dust could cause lung tumors and that silicosis patients seemed to have an increased risk for pulmonary and gastric malignancies. It was noted that only during the past 3 to 5 years have adequate industrial hygiene data become available that enables an evaluation of possible dose response relationships between occupational silica exposure and cancer to be performed. In the area of tumor biology, two recent studies conducted in rats have shown that inhalation of silica dust can induce lung tumors, mostly adenocarcinomas, that occur adjacent to silicotic granulomas. These effects have not usually been observed in other rodent species. Silica has been shown to have the capability of binding to DNA in- vitro and appears to increase expression of transforming growth factor beta1. These effects were cited as providing a possible biochemical mechanism for silica carcinogenicity. A number of more recent epidemiological studies have indicated that silicotics have significantly increased risks for cancer. It was noted that these findings must be considered in the context that silicotics are less healthy than the general population and that this may make them more susceptible to lung cancer induction. Few conclusive dose response relationships examining this possibility have been established. Future research needs include determining what is the best evidence that can be used to identify the probable health effects resulting from silica exposure and eliminating the exposure conditions that can result in silicosis and possibly cancer.
NIOSH-Author; Silica-dusts; Occupational-exposure; Industrial-hygiene; Respiratory-system-disorders; Epidemiology; Lung-cancer; In-vivo-studies; Laboratory-animals; Risk-analysis; Molecular-biology
Scandinavian Journal of Work, Environment and Health