Lung cancer, like all cancers, arises when there is an unrestrained growth of lung cells due to mutations caused by various factors. It is the most common cancer in the world and is responsible for approximately 1.4 million deaths annually.

Here are some facts relating to this deadly disease:

Types

There are two major types of lung cancer; small-cell lung carcinoma (SCLC) - it accounts for 15% of the disease and is usually caused by smoking and typically begins in the large airways of the lungs from where it can spread to the brain. The other is non-small-cell lung carcinoma (NSCLC) which comprises 80% of the cases. It has three main types--adenocarcinoma, squamous cell carcinoma and large cell carcinoma. NSCLC arises from the epithelial cells lining the larger and smaller airways.

Causes

The main causes of lung cancers include smoking (active and passive), radon gas, asbestos, familial predisposition, air pollution and lung diseases.

Symptoms

1 A persistent cough or worsening of an existing chronic cough
2 Prolonged chest or shoulder pain
3 Unexplained weight loss and/or fatigue
4 Coughing up blood
5 Repeated chest infections
6 Breathing problems

Diagnosis

A chest x-ray is the first diagnostic step taken to detect cancer, if a person shows symptoms of infection. CT imaging and bronchoscopy are used to gather more information about the extent or location of a tumour.

Stages

NSCLC is divided into four stages depending on the severity of a case.

Stage 1-it is confined to the lung

Stage II&III-it is has spread locally but is confined to the chest. (Stage III denotes extent and invasiveness of the tumours)

Stage IV- it has spread from the chest to other parts of the body

SCLC is classified depending on whether the cancer is limited or extensive.

Treatment

Methods of treatment include surgery, chemotherapy, and/or radiation therapy depending upon the stage and type of lung cancer and also the patient's overall heath condition.

Prevention

Cessation of smoking, reducing radon levels at home, limiting air pollution, eliminating passive smoking and avoiding carcinogens at work; these are some of the measures an individual and the public at large can take to prevent lung cancer.