Causes and prevention

Here are some facts about smoking and lung cancer:

• The more you smoke, the more likely you are to get lung cancer but the length of time you have been a smoker is even more important than how many cigarettes you smoke a day;
• Starting smoking at a young age is even more harmful than starting as an adult;
• Stopping smoking reduces your risk of lung cancer compared to continuing to smoke.  The sooner you quit, the better your health - but it's never too late;
• Passive smoking (breathing in other people's cigarette smoke) increases the risk of lung cancer, but it is still much less than if you smoke yourself.

Some other things increase lung cancer risk.  But they increase the risk by only a small amount and far less than smoking.  They are:

• Exposure to radon gas;
• Exposure to certain chemicals;
• Air pollution;
• Previous lung disease;
• A family history of lung cancer;
• Past cancer treatment;
• Previous smoking related cancers;
• Lowered immunity.

The most effective measure that can be taken to prevent the development of lung cancer is to stop smoking.  Reducing exposure to passive smoking is also an effective method of prevention.

Symptoms and screening

The symptoms of lung cancer may include:

• Having a cough most of the time;
• A change in a cough you have had for a long time;
• Being short of breath;
• Coughing up phlegm (sputum) with signs of blood in it;
• An ache or pain when breathing or coughing;
• Loss of appetite;
• Tiredness (fatigue);
• Losing weight.

    Other less common symptoms of lung cancer are usually associated with more advanced lung cancer. They include:

• A hoarse voice;
• Difficulty swallowing;
• Changes in the shape of your fingers and nails called finger clubbing;
• Swelling of the face caused by a blockage of a main blood vessel (superior vena cava obstruction);
• Swelling in the neck caused by enlarged lymph nodes;
• A constant ache or pain in your chest or shoulder that has lasted some time;
• Pain or discomfort under your ribs on your right side (from cancer cells in the liver);
• Shortness of breath caused by fluid around the lungs (called a pleural effusion).

Some types of lung cancer cells produce hormones that get into the bloodstream.  Pins and needles or numbness in the fingers or toes:

• Muscle weakness;
• Drowsiness, weakness, dizziness or confusion;
• Breast swelling in men;
• Blood clots (thrombosis).

These symptoms are uncommon with lung cancer but they can happen.  Lung cancer growing right at the top of the lung is called a pancoast tumour.  These tumours can cause very specific symptoms.  The most common is severe shoulder pain or pain that travels down the arm.  Pancoast tumours can also cause a collection of symptoms called Horner's syndrome.  These are:

• Drooping or weakness of one eyelid;
• A small pupil in that eye;
• Loss of sweating on that same side of the face.

These symptoms of Horner's syndrome are caused by the tumour pressing on or damaging a nerve that runs up from the neck to that side of the face.

Screening means testing people for early stages of a disease before they have any symptoms.  It is an important part of health care for some cancers.   For screening to be introduced, we need a test that is simple, quick, not too expensive, and not harmful. Current tests such as X-rays can't usually show early stage cancers and they have some risks.  The lungs are very sensitive to radiation and frequent X-rays may cause lung damage.  X-rays can also find lung changes that look like cancer and need to be checked by further tests, such as a biopsy.  The further tests can cause problems for some people.