One of the major differences is in the incidence rates of the two diseases
About 222,500 new cases of lung cancer are reported annually making it the second most common cancer in the United States. The incidence rate of pleural mesothelioma was 3.05 cases per 100,000 people, according to a study conducted by the Centers for Disease Control and Prevention (CDC) in 2013.
Mesothelioma is solely a result of prolonged asbestos exposure and has an average latency period of 40 years. Lung cancer typically develops at least 10-30 years after smoking tobacco. Asbestos exposure can also cause asbestos-related lung cancer or increase the risk of developing lung cancer in smokers, but it is to be noted that tobacco does not have an influence on the risk of developing mesothelioma.
The location of the cancerous tumor is another differentiating factor between pleural mesothelioma and lung cancer. Most of the times, mesothelioma develops on the protective lining of the lungs, pleura or on the surface of the lungs. Patients with pleural mesothelioma will either develop pleural thickening or pleural effusion whereas patients with lung cancer may not necessarily have the pleural thickening.