Lung cancer is primarily classified into two main types: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). The clinical characteristics, biological behavior of cancer cells, and treatment principles vary significantly depending on the type of lung cancer.

Many cases of lung cancer may not present symptoms until the disease has spread. One of the earliest symptoms, coughing, is often considered normal by smokers, which further delays early diagnosis.

Symptoms of lung cancer include:
• Cough
• Shortness of breath (Dyspnea)
• Chest pain
• Sudden weight loss
• Coughing up blood (Hemoptysis)

Having accurate information about lung cancer, recognizing early symptoms, and undergoing regular screening programs if risk factors are present are crucial for the proper diagnosis and treatment of the disease.