Lung Cancer

Lung cancer is the second most common deadliest cancer developing from bronchi, bronchioles, lung, or tracheal parenchyma with the active or passive tobacco smoke exposure being the most common cause. Approximately 1.8 million people are diagnosed with lung cancer, and approximately 1.6 million people die annually due to lung cancer accounting for more than all prostate, breast, and colon cancer combined. Besides tobacco smoke exposure, second-leading lung cancer mortality cause is environmental radon exposure, whereas lung cancer as a distinct entity in never-smokers is the seventh most common worldwide cancer cause mostly occurring in women implicated to be due to hormonal, geographic, cultural, and genetic difference factors. Median cancer presentation age is 70 years. Lung cancer is separated into NSCLC and SCLC types. NSCLC accounts for 80–85% of lung cancer cases, and less than half of the patients are resectable on initial presentation and 25% of the NSCLC patients have locally advanced disease, whereas 30% of SCLC patients present with limited-stage disease. Basic concepts that are crucial to understanding lung cancer are reviewed in depth in this chapter.