Lung Cancer

Lungs are the two organs in the chest which transfer oxygen that we breathe in into the blood, and breath out the CO2 generated in the body. Cancer of the lungs is categorized depending upon the type of cells involved. The two categories are:

1. Small-cell cancer.
2. Non-small cell cancer.

Small-cell cancer grows and spreads fast in the body.

About one-fourth of all lung cancers are of this type. It is also called oat-cell cancer, because its cells, under the microscope, look like oat grains. This type is not much associated with smoking.

Non-small cell cancer has under it three varieties:

1.Squamous or epidermoid.
2. Adenocarcinoma.
3. Large cell cancer.

Squamous cell cancer is the one which is associated with tobacco smoking. All these three varieties grow less rapidly than the small cell cancer and hence their treatment is more or less on similar lines.
Lung cancer accounts for more than 50 per cent of all male deaths from cancer in the Western countries where it is widely prevalent. Of all deaths from lung cancer, small cell carcinoma accounts for 25 per cent, squamous for 50 per cent, large cell 10 per cent and adenocarcinoma 10 per cent.

Lung cancer arises from bronchial epithelium or mucous glands and at an early stage may occlude the bronchial lumen. When the cancer mass obstructs a major bronchus, it causes collapse of the lung.

A tumor arising from a peripheral bronchus may attain a very large size without producing a significant degree of collapse.

It may involve the pleura either directly or by lymphatic spread, causing a pleural effusion which is often blood­stained. It may also extend into the chest wall and cause severe pain. The cancer or its lymph node metastases may extend into the mediastinum, the space between the two lungs in the chest. The incidence of lung cancer in India is about 4 per cent of all cancers.

Causes:

After the Second World War, the incidence of lung cancer has sharply increased in developed countries. In England and Wales, the death rate is continuously increasing -- having risen to 37.5 deaths in males and 5.8 deaths in females per 100,000 population in 1975.

Cancer of the lung particularly squamous cell type, has increased in incidence all over the world where the tobacco is smoked, in particular, tobacco in the form of cigarettes. The risk of getting cancer of the lungs is increased in accordance with the number of cigarettes smoked. Those who leave smoking, lessen the risk of getting lung cancer.

Symptoms:

• Cough, sometimes with blood in the phlegm
• Fever
• Loss of appetite
• Loss of weight
• Hoarseness of voice sometimes
• Pain in the chest
• Breathlessness
• Clubbing of the finger nails
• Metastasis to the brain are commonest from lung cancer, producing a variety of symptoms.

Diagnosis:

• History taking
• Physical examination
• Routine: Blood: Hb may be decreased
• TIC may be increased
• In DLC, polymorphs may be increased
• ESR is raised
• X-ray of the chest, many a time, indicates suspicion of cancer
• Sputum examination for cancer cells is sometimes helpful

Special:

CT scan can reveal the presence of cancer in the lung, as well as its spread in the glands.

Fine needle aspiration biopsy examination may establish diagnosis.

Bronchoscopy may show the presence of cancer in the bronchi. A punch biopsy taken from a suspicious site and examined histologically, can reveal the true identity of the lesion. Bronchial aspirate examination histologically, may reveal the nature of the lesion.

Additional:

In case there is suspicion of the presence of cancer secondaries in other organs such as liver, bones or brain, an ultrasound examination of the liver, or CT scan of the other organs can reveal the diagnosis.

Secondary Tumors of the Lung:

Blood borne metastatic deposits in the lungs may be derived from primary cancer almost anywhere in the body. The secondary deposits are usually multiple and bilateral.