Occupational silica exposure and lung cancer risk: a review of epidemiological studies 1996–2005

Abstract

In this re-analysis, the association with lung cancer was consistent for silicotics, but the data were limited for non silicotic subjects and not easily explained for undefined silicosis status workers. This leaves open the issue of dose-risk relation and pathogenic mechanisms and supports the conclusion that the carcinogenic role of silica per se in absence of silicosis is still unclear.

Silica binding and toxicity in alveolar macrophages

“…The hydroxyl radical is the most potentially damaging ROS (due to very short halflife, high reactivity, and lack of effective elimination) to the lung, but it is produced to any significant degree only in the presence of contaminants such as iron (Fenton reaction). Crystalline silica regardless of source, purity, and age is capable of inducing various lung pathologies [6]. Therefore, it is reasonable to assume that free radicals are not the only cause of silica-induced disease.…”

“…There is evidence that silica exposure can also be linked to the development of autoimmune diseases such as scleroderma (systemic sclerosis), rheumatoid arthritis, chronic renal disease and lupus [4]. Additionally, silica inhalation is believed to be the cause of some rare lung cancers [5], although significant relative risk (RR) of lung cancer is only associated with individuals that already have silicosis from silica exposure [6]. Based on the relative dose-response or exposureresponse relationships in experimental animal studies, silica appeared to be a uniquely hazardous particle type [7].…”

A Stone Miner With Silicosis- Case Report

“…4,5 Risk of lung cancer is 3 folds more in silicosis than in general population. 6 Patients with silicosis are 20-30 folds more susceptible to pulmonary tuberculosis. 7,8 After inhalation of the silica dust particles, the macrophages ingest them, release cytokines and initiate an inflammatory reaction and stimulate fibroblasts ultimately leading to fibrosis and formation of pulmonary nodular lesions.…”

Pneumoconiosis

“…Smoking cessation is particularly important as silica is a carcinogen, and individuals with silicosis are at increased risk of lung cancer. 10,11 The development of silicosis also increases the risk of contracting pulmonary tuberculosis (TB), which is an important consideration in areas where TB is endemic, especially as the typical upper lobe chest X-ray changes of pulmonary TB may be masked by the presence of silicosis. 12 Less common but well recognised complications include the development of connective tissue diseases such as scleroderma and SLE and, rarely, glomerulonephritis.…”