Toxins that end up in the lungs can result in many different forms of lung injury, including cancer. Mesothelioma from asbestos exposure and lung cancer from smoking are two common examples. These conditions are unique in that asbestos is the main cause of mesothelioma, and smoking is the main cause of lung cancer. However, because asbestos exposure has been linked to certain blue-collar jobs, and because blue-collar workers are more likely to be smokers, doctors began to wonder whether asbestos and smoking impact each other. In particular, doctors began to wonder whether smoking can increase the cancer risks of asbestos exposure, and if asbestos can increase the cancer risks of smoking.
Risks of Lung Cancer in People Exposed to Asbestos
Multiple studies have been done about the effect of smoking and asbestos on the lungs. In general, the studies showed that smoking did not increase the risk of mesothelioma in people who had been exposed to asbestos. However, the studies also showed that when people who smoke were exposed to asbestos, their risk of lung cancer increased. The amount of the increase varied widely in the studies. Nonetheless, the increased risk of lung cancer in smokers exposed to asbestos has convinced doctors that asbestos may make smokers more susceptible to lung cancer.
How Asbestos Increases Lung Cancer Risks in Smokers
Doctors are still investigating how asbestos increases the risk of lung cancer in smokers. Studies have shown that cigarette smoke and asbestos have a damaging synergistic effect in the lungs which can eventually lead to cancer. In other words, when asbestos and the chemicals in cigarette smoke team up, they cause cancer more readily than each of them would on their own. Several possible mechanisms may be involved:
-Inflammation: Some doctors think that the increased cancer risk is because both smoking and asbestos exposure cause chronic inflammation in the lungs. In turn, inflammation can lead to immune system problems and infections. Data suggest that asbestos exposure causes inflammation through different chemical mechanisms than smoking. For this reason, doctors think that the lung inflammation from asbestos and smoking may be greater than the inflammation from smoking alone. When combined with the cancer-causing effects of cigarettes, lung cancer may result.
-Penetration: Some research suggests that the presence of asbestos fibers inside the lungs may make it easier for the carcinogens in cigarette smoke to penetrate the lungs.
-Immune system: Asbestos fibers in the lungs cause the immune system to be constantly activated. The immune system is made up of many types of cells. One type of immune cell is a large white blood cell called a macrophage. Under normal circumstances, macrophages will attempt to engulf and digest harmful substances. When asbestos fibers penetrate the lungs, macrophages are triggered and try to digest the asbestos fibers, a job they cannot do. However, the macrophages constantly remain activated. In turn, this harms the ability of the rest of the immune system to function as it should. Immune system impairment has been linked to cancer.
-Free radicals: Chemicals called free radicals can damage tissue. Blue asbestos (amosite, crocidolite, tremolite) in particular contains substances with free radicals that can lead to extensive tissue damage. Doctors think this damage may contribute to lung cancer if the person also smokes.
Reducing the Risk of Lung Cancer in Smokers Exposed to Asbestos
Doctors recommend a couple of different strategies to reduce the lung cancer risk of smokers who have been exposed to asbestos in the past:
-Smoking cessation: Although past lung damage from asbestos and smoking may be chronic, it is possible to stop further lung damage by stopping smoking. Smoking cessation is linked to a reduced risk of lung cancer. Many different therapies are available to help you quit smoking. Your doctor will be able to advise you on the treatment that is best for you.
-Cancer screenings: By making sure that your doctor is aware of your past asbestos exposure and smoking history, they will be able to monitor you to catch any cancer more quickly. Cancer screenings may include non-invasive tests like chest X-rays.
Asbestos and smoking are a dangerous combination which can increase the risk of lung cancer. If you have a history of asbestos exposure and smoke, it is important to try to quit smoking to reduce your cancer risk. Luckily, by quitting smoking, you will be able to put the brakes on lung damage and increase your chances of having healthy lungs.