Lung cancer is a malignant tumour of the lungs. Most commonly it is bronchogenic carcinoma (about 90%). Lung cancer is the most lethal malignant tumour worldwide, causing up to 3 million deaths annually.
The most important risk factor for lung cancer is smoking.
Treatment and prognosis depend upon the histological type of cancer and the stage (degree of spread). Possible treatment modalities include surgery, chemotherapy) and/or radiotherapy.
Signs and symptoms
Common symptoms that suggest lung cancer include:
dyspnea (shortness of breath)
hemoptysis (coughing up blood)
chronic cough
wheezing
chest pain
cachexia (weight loss), fatigue and loss of appetite
dysphonia (hoarse voice)
clubbing of the fingernails
If the cancer grows into the lumen it may obstruct the airway, causing breathing difficulties. This can lead to accumulation of secretions behind the blockage, predisposing the patient to pneumonia.
Many lung cancers have a rich blood supply. The surface of the cancer may be fragile, leading to bleeding from the cancer into the airway. This blood may subsequently be coughed up.
Depending on the type of tumor, so-called paraneoplastic phenomena may initially attract attention to the disease. In lung cancer, this may be Lambert-Eaton myasthenic syndrome (muscle weakness due to auto-antibodies), hypercalcemia and SIADH. Tumors in the top (apex) of the lung, known as Pancoast tumors, may invade the local part of the sympathetic nervous system, leading to changed sweating patterns and eye muscle problems (a combination known as Horner's syndrome), as well as muscle weakness in the hands due to invasion of the brachial plexus.
In many patients, the cancer has already spread beyond the original site by the time they have symptoms seek medical attention.
Common Cancer Types
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