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Bronchogenic carcinoma is one of the most common cancer in men. It usually affects during 50 to 70 years of age. Cigarette smoking is considered as the major risk factor of the bronchogenic carcinoma. Studies have shown that the persons, who smoked at least 20 cigarettes a day for more than 20 years, are having the highest risk of bronchogenic carcinoma. The passive smokers are also having a much higher risk of the bronchogenic carcinoma. Radon, a naturally occurring radioactive gas, is another major risk factor. It has been observed that the workers exposed to asbestos have a higher risk of bronchogenic carcinoma. Exposure to certain chemicals such as bichloromethyl ether and chloromethyl ether may cause the bronchogenic carcinoma. Other risk factors include exposure to heavy metals, air pollutants, industrial toxins and ionising radiation. Lung scars and chronic obstructive airway disease may also lead to genesis of the bronchogenic carcinoma.
Bronchogenic carcinomas are of two major types, i.e. the small cell bronchogenic carcinomas and the non-small cell bronchogenic carcinomas. The small cell bronchogenic carcinomas comprise about 25 per cent of the bronchogenic carcinomas while remaining 75 per cent are the non-small cell bronchogenic carcinomas. Non-small cell bronchogenic carcinomas are further divided into the squamous cell carcinoma, adenocarcinoma and the large cell carcinoma.
In about 20 per cent cases, the bronchogenic carcinoma remains asymptomatic in early stages of the disease. Chronic cough, haemoptysis and dyspnoea are earliest and the most common symptoms. The other signs & symptoms include chest pain, wheeze, recurrent pneumonia, persistent chest infection, weight loss and unexplained hyponatraemia. There may occur lymphadenopathy and hepatomegaly. Pressure of the tumour on the recurrent laryngeal nerve may lead to hoarseness of the voice, whereas pressure on the oesophagus may cause dysphagia. Stridor may occur due to pressure on the trachea and the main bronchus. There may occur paralysis of one half of the diaphragm due to the phrenic nerve palsy. Endocrine related signs of the bronchogenic carcinoma may be seen including gynaecomastia, clubbing of the fingers, arthritis and neuropathy. Symptoms like confusion and drowsiness may appear due to hypercalcaemia. There may be weakness of the muscles due to hyperkalaemia. The bronchogenic carcinoma may invade the mediastinum, pleura, chest wall and the pericardium. Invasion into the mediastinum may lead to obstruction of the superior vena cava. Involvement of the pleura may lead to the pleural effusion, whereas involvement of the intercostal nerves and the brachial plexus may lead to pain in the chest and the arms. Bronchogenic carcinoma usually metastasises through blood stream to the liver, brain, bone, skin and the adrenal glands. It also involves paratracheal and supraclavicular lymph nodes.
Staging of the small cell bronchogenic carcinoma is done as follows:
In limited stage of the small cell bronchogenic carcinoma, the tumour is located in one of the lungs along with involvement of the regional lymph nodes.
In extensive stage of the small cell bronchogenic carcinoma, the tumour involves other tissues in the chest or metastasises to distant parts of the body.
Recurrent small cell bronchogenic carcinoma is the one that reappears after an apparent recovery in response to the initial treatment.
Staging of the non-small cell bronchogenic carcinoma is done as follows:
In occult stage of the non-small cell type of bronchogenic carcinoma, the malignant cells are traced in the sputum but tumour is not found in the lungs.
In stage 0 (carcinoma in situ) of the non-small cell bronchogenic carcinoma, the tumour is located at one site within the lung.
In stage I of the non-small cell bronchogenic carcinoma, the tumour spreads within the lung. In stage II of the non-small cell bronchogenic carcinoma, the tumour involves the regional lymph nodes.
In stage III of the non-small cell bronchogenic carcinoma, the tumour involves the chest wall; or the diaphragm; or lymph nodes in the mediastinum; or lymph nodes in other side of the chest; or lymph nodes in the neck. The stage III of the non-small cell bronchogenic carcinoma is further divided into III-A, in which surgery is possible and III-B, in which surgery is not possible.
In stage IV, the non-small cell bronchogenic carcinoma metastasises to distant parts of the body.
Recurrent non-small cell bronchogenic carcinoma is the one that reappears after an apparent recovery in response to the initial treatment.
Procedures used to diagnose and evaluate the bronchogenic carcinoma include chest X-rays, CT scan, MRI, bronchoscopy, mediastinoscopy and biopsy.
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This content is for information and educational purposes only and should not be perceived as medical advice. Please consult a certified medical or healthcare professional before making any decision regarding your health using the content above.
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Bronchogenic Carcinoma (Lung Cancer)