is the deadliest cancer
in most countries. Lung cancer is mainly due to tobacco use and is very aggressive because metastasis occurs quickly. Apart from a history of smoking, lung cancer is also suspected in the presence of a persistent cough, difficulty breathing, chest pain, sometimes coughing up blood, and often a decline in general health. A chest X-ray is the first examination, sometimes a CT scan, and in the case of a suspicious lesion, an endoscopy or biopsy
of the lesion is necessary to identify the constituent cells. Conventional surgery, chemotherapy
, and radiotherapy are used depending on the progression of the cancer. Note that the lung is an organ often affected by the metastasis of other cancers.