Lung cancer is the leading cause of cancer-related deaths among men and the second among women after breast cancer. In 2012, the total number of deaths associated with lung cancer was 1.56 million with an additional 1.82 million new cases worldwide.
Seventeen out of 20 lung cancer cases are attributed to long-term smoking. Among the other causes of lung cancer include asbestos which, when combined with smoking, unfortunately, increases the likelihood of lung cancer by up to 4,500 percent or 45-fold. As such, individuals who smoke while working in asbestos mines as well as manufacturing facilities of asbestos products have a greater risk of developing lung cancer than those who do not smoke. It is also for this reason that one of the poor prognostic indicators of mesothelioma is smoking.
Asbestos is a very common material used in many building and construction materials as well as other commercial and industrial applications. This has left a lot of individuals working in these establishments chronically exposed to asbestos. The microscopic fibrils of asbestos can get airborne and can reach the respiratory passages and the lungs when inhaled. They are then trapped in the lungs. Over time and with repeated exposure to asbestos, these microfibrils accumulate and lead to inflammation, scarring, and other physiologic and morphologic changes in the lung parenchyma.
Just like mesothelioma, asbestos lung cancer develops when the inflammatory processes associated with asbestos microfibril adhesion activate a series of oncogenes that favor the development of cancer cells. On the other hand, tumor suppressor genes are also inactivated leading to the formation of a cancerous growth. Studies reveal that larger asbestos fibers have the tendency to lodge in the lung parenchyma itself while smaller asbestos microfibrils can diffuse into the lung parenchyma and lodge into the mesothelial lining of the lungs, the pleura. This gives rise to mesothelioma while the larger asbestos fibers cause asbestos lung cancer.
Small cell lung cancer (SCLC) is one of two types of asbestos lung cancer accounting for 1 in 5 cases. It is the most aggressive type of asbestos lung cancer with very limited treatment options. Additionally, because of its nature, the prognosis is rather poor and life expectancy is relatively short. Only around 6 percent of patients get to live more than 5 years after diagnosis. The cancer progression is rather fast, rendering surgery virtually impossible because of rapid metastasis to adjacent organs as well as more distant body parts such as the brain, the bones, adrenal glands, and the liver.
Non-small cell lung cancer (NSCLC) is another type of asbestos lung cancer which accounts for 4 out of 5 asbestos lung cancer cases. Unlike SCLC however, NSCLC has a better prognosis because it is less aggressive paving the way for more treatment options. On the average, more than 17 percent of NSCLC patients get to live more than 5 years after diagnosis.
Asbestos lung cancer, as compared to mesothelioma, has a relatively poor prognosis with an expected shorter life span. This pertains to small cell lung cancer types or SCLC. When it comes to survival rate, non-small cell lung cancer (NSCLC) has an estimate of 20 months on the average. On the other hand, SCLC cancer type of asbestos lung cancer typically has a median survival rate of 8 months.
Like all cancers, prognosis can be improved with early detection and diagnosis. However, for small cell lung cancer, time is of the essence because of the rapid progression of the cancer. In most cases, surgery will often prove inappropriate because the cancer would have already spread to other body organs. Oftentimes, 3 of 5 patients with SCLC are first diagnosed when they are already in Stage IV.
The relationship between asbestos lung cancer and smoking is well-understood. Smoking greatly diminishes the mucociliary protective mechanism of the lungs. These hair-like projections that line the inner surface of the airways function in sweeping foreign particles out from the lungs. These are damaged in chronic smoking. When asbestos fibers are inhaled, the mucociliary mechanism cannot sweep the fibers off the inner surface of the airways. This predisposes the individual to the faster accumulation of asbestos fibers in the lung which, in turn, increases the risk of developing asbestos lung cancer.
Like mesothelioma, asbestos lung cancer is a very challenging health condition to treat. Early detection is quite difficult rendering treatments virtually useless.