Lung cancer is one of the most common and deadly cancers worldwide, strongly linked to tobacco smoking but also influenced by air pollution, occupational exposures, and genetic susceptibility. It is broadly divided into non small cell lung cancer (NSCLC), which makes up about 85 percent of cases, and small cell lung cancer (SCLC), which is less common but more aggressive.

Research has revealed that lung cancer is fundamentally driven by genetic and molecular alterations. In NSCLC, frequent changes occur in genes that control cell growth and survival, such as EGFR, ALK, ROS1, BRAF, and KRAS. Identifying these alterations in tumor tissue or circulating DNA allows clinicians to match patients with targeted therapies that block the specific abnormal proteins. These drugs often improve response rates and progression free survival compared with traditional chemotherapy, though resistance eventually develops.

Another major research focus is immunotherapy, which harnesses the patient’s immune system. Checkpoint inhibitors targeting PD 1, PD L1, and CTLA 4 can restore anticancer immune responses and have transformed treatment for many patients with advanced NSCLC and some with SCLC. Biomarkers such as PD L1 expression and tumor mutational burden are being studied to better select patients for these drugs and to optimize combinations with chemotherapy, radiation, and targeted agents.

Early detection is crucial. Studies of low dose CT screening in high risk individuals have shown reductions in lung cancer mortality by finding tumors at a more curable stage. Ongoing research aims to refine screening criteria and to complement imaging with blood based biomarkers to improve accuracy and cost effectiveness.