Lung Cancer

INTRODUCTION
Lung Cancer, growth of malignant cells affecting, initially, the lung. Cancer forms when a lung cell undergoes alterations to its DNA , leading to uncontrolled cell growth. Proliferation continues until a tumour forms. The process of metastasis (spread) takes place when cells break off from the tumour and travel via the blood or lymphatic system, lodging in other organs. There they begin to multiply, forming other tumours. Lung cancer falls into two groups: small cell and non-small cell carcinomas. Small cell lung cancer (SCLC) is also called oat cell carcinoma because of the cells’ shape. About 25 per cent of lung cancers are of this type.
Non-small cell lung cancer (non-SCLC) comprises squamous cell (or epidermoid) cancer, which arises from cells that line the airways of the lung, and is the most common form of lung cancer; Adenocarcinoma, which arises in mucus-producing cells which line the upper airways of the lung; and large cell carcinoma.

SYMPTOMS
The symptoms of lung cancer are a persistent hacking cough, blood in the sputum, wheezy breathing, pain in the shoulder or chest, neck or facial swelling, and recurring pneumonia or bronchitis.

CAUSES
A huge proportion—90 per cent—of lung cancers is caused by smoking. About 6 per cent may be linked to a naturally occurring radioactive gas, radon. Other causes are passive smoking (breathing in smoke from other people’s cigarettes, cigars, or pipes) and exposure to certain substances such as asbestos. Diet may also be involved; studies have shown that a diet low in fresh fruit and vegetables may increase risk.

TREATMENT
Lung cancer is difficult to control with existing treatments. Less than 10 per cent of patients survive for five years after diagnosis. This is mainly because the cancer has usually spread before it is diagnosed and surgery is therefore not an option. Radiotherapy and chemotherapy can help improve a patient’s quality of life and in some cases extend life.
Small cell lung cancer spreads rapidly and is sensitive to drugs, so chemotherapy can control it for a while. However, the cells may become drug resistant and therefore the periods of remission become shorter.
Surgery may be possible in patients with non-SCLC if the cancer is confined to the original tumour site and has not metastasized. Unfortunately, it is common for this type of cancer to return. Treatment for advanced cancer may include radiotherapy, chemotherapy, or laser therapy.