What is it?
Lung cancer is the uncontrolled growth of malignant (cancerous) cells in lung tissue and can be caused by numerous environmental carcinogens, particularly tobacco smoke.

Types of lung cancer
There are two main forms of lung cancer:

• Small cell lung cancer (SCLC) and;
• Non-small cell lung cancer (NSCLC)

NSCLC is the most common form of lung cancer. It is important to distinguish between NSCLC and SCLC because the two types of cancer are treated in different ways.

There are three types of NSCLC;

• adenocarcinoma,
• squamous cell carcinoma and;
• large cell carcinoma.

Adenocarcinoma is known to occur more frequently in women.

Squamous cell carcinoma is less common, and is known to occur most frequently in men and older people.

The rarest type of lung cancer is large cell lung cancer. It is known to grow quicker and spread rapidly throughout the lung compared to the other types of lung cancer.

Risk Factors
The greatest risk factor known for developing lung cancer is smoking. The level of risk is primarily affected by the length of time someone has smoked.

Passive smoking is also a risk factor and is known to increase the likelihood of developing lung cancer in non-smokers. Other risk factors include exposure to asbestos and radon gas, scarring from previous lung disease (e.g. tuberculosis), family history of lung cancer and past cancer treatment. 

Diagnosis and Treatment Options
The diagnosis and treatment of lung cancer can be complicated as the disease spreads very easily through the lymphatic system. This spread of cancer cells to other parts of the body is called metastasis and means that for most patients the treatment will not cure the cancer.

Currently, there are three standard treatments for lung cancer:

• Surgery
• Radiotherapy and;
• Chemotherapy

One or more of these therapies may be used, depending on the type of cancer, the stage of the disease, and overall health and age of the patient. Both surgery and radiation can cure lung cancers when they are localised (they have not spread to any surrounding tissue).

For advanced NSCLC, chemotherapy is the most common treatment option. This can be administered with or without radiotherapy, as appropriate for the patient. Chemotherapy is generally given as a two-drug combination.

Newer treatments
In addition to traditional chemotherapy, a number of newer therapies are becoming available. These are known as targeted therapies, which provide comparable effectiveness to chemotherapy but without the unwanted side effects and with additional convenience benefits.