By Treven Pyles
Posted on February 26th, 2019
A potential link between non-malignant asbestos-related diseases such as asbestosis and malignant asbestos-related diseases such as lung cancer had been a long debatable. According to the latest studies, the risk of lung cancer is higher for persons with asbestosis compared to persons without asbestosis.
One of the hypotheses suggests that asbestosis and lung cancer were considered to be two consecutive stages of the asbestos-related disease and the asbestos-induced fibrosis of the lungs promoted the growth of cancerous cells. However, another hypothesis argued that asbestosis and lung cancer are separate diseases with the same cause but have different pathogenic mechanisms.
According to a recent study conducted at the School of Earth & Environmental Sciences at Queens College in New York, it was found that the combination of three risk factors such as asbestos exposure, asbestosis, and smoking can increase the chances of developing lung cancer. The study included a large cohort of more than 50,000 non-exposed control group and asbestos-exposed individuals. It was found that while every risk factor was associated with increased risk of developing lung cancer, the combination of two risk factors increased the risk further, and the combination of all the three risk factors enhanced the risk of developing lung cancer by 37 times. These results have been published in the online version of the American Journal of Respiratory and Critical Care Medicine.
Asbestosis, though not a prerequisite for carcinogenesis, is associated with an elevated risk of developing lung cancer when compared to asbestos-exposed individuals without asbestosis. Usually, non-small cell lung carcinoma develops in patients with asbestosis and at a rate 8-10 times higher than those without asbestosis.
Asbestos exposure increases mortality due to lung cancer even in non-smokers and the presence of asbestosis will further increase the risk of lung cancer. In non-smokers, exposure to asbestos increases the death rate from lung cancer by 5.2 times, while in smokers, asbestos exposure increases the death rate from lung cancer by more than 28 times. Further, it is to be noted that asbestosis increases the risk of developing lung cancer in both smokers and non-smokers that are exposed to asbestos. Interestingly, there is a 36.8 fold increase in the death rate from lung cancer among asbestos-exposed smokers with asbestosis. With all the evidence available, it can be derived that asbestosis serves as a better predictor and a marker of increased lung cancer risk compared to other measures of asbestos exposure. Moreover, as non-malignant asbestos-related illnesses indicate an increased risk of lung cancer, diagnostic strategies can be formulated accordingly as newer tools such as low-dose computed tomography of the chest are being available.
As asbestosis is an irreversible and incurable lung disease, palliative treatment is the only option. In advanced stages of asbestosis, supplemental oxygen is prescribed when breathing becomes difficult.
Most work-related lung diseases are caused by repeated and prolonged exposure, but even a significant, single exposure to an unsafe agent can damage the lungs. Asbestosis screening is a must in every individual with prolonged asbestos exposure or in any person who believes he/she has had prolonged asbestos exposure. Some occupations that put workers at risk for lung function loss due to asbestos exposure on the job include:
However, signs such as breathing problems in people at risk of developing asbestosis indicate the need for undergoing initial testing, which includes an X-ray of the chest, four views that should be reviewed by a board-certified B-reader. B-Readers are physicians trained and certified in asbestos-related lung x-rays, by the National Institute for Occupational Safety and Health. Practically, a B-Reader looks for changes or abnormalities on the chest x-ray that can be caused by inhalation of particles such as silica and asbestos.
Further tests such as pulmonary function tests, blood tests, high-resolution CT scan, and/or biopsy will be recommended if necessary.