Lung Cancer

For most lung cancer cases, genetic mutations are somatic (meaning they happen in cells only specific to that individual and are not inherited). In rare cases, genetics can play a role in the development of lung cancer, particularly for people who have inherited gene mutations on chromosome 6 (which accounts for approximately 6% of all DNA in cells). However, the most common cause of lung cancer is cigarette smoking.

Exact causes of lung cancer are not fully known, especially in people who develop lung cancer without any known risk factors. However, factors have been found to increase the risk of developing lung cancer include:

• Smoking – Cigarette smoking carries a significantly higher risk of developing lung cancer when compared with non-smokers. It is estimated that lung cancer cases as a result of cigarette smoking contribute to 90% of all cases in men and 65% in women

• Second-hand smoking – There is an increased risk for non-smoking people who breath in the cigarette smoke of others. Living with someone who smokes can increase your risk for lung cancer by approximately 20-30%

• Exposure to asbestos and other toxins – People who have been exposed to asbestos (traditionally used in building materials) and other toxins such as radon (a radioactive gas used in the mining industry) have an increased risk of developing lung cancer

• Age – The risk of developing lung cancer increases as people age. Most lung cancers are diagnosed in people over the age of 60

• Medical history – People who have a medical history of lung disease such as emphysema or fibrosis of the lung may have an increased risk of developing lung cancer

About 11 in 500 Australians develop lung cancer each year. It’s the fifth most common cancer type, with more men than women developing the disease, and the leading cause of cancer death in Australia.

There are a number of lifestyle-related factors which can reduce your risk of developing lung cancer, including:

• Quitting smoking – Cigarette smoking carries a significantly higher risk of developing lung cancer when compared with non-smokers. It’s estimated that lung cancer cases because of cigarette smoking contribute to 90% of all cases in men and 65% in women

• Avoiding second-hand smoke – There’s an increased risk for non-smoking people who breathe in the cigarette smoke of others. Living with someone who smokes can increase your risk for lung cancer by approximately 20-30%

• Avoiding exposure to asbestos and other toxins – People who have been exposed to asbestos (traditionally used in building materials) and other toxins like radon (a radioactive gas used in the mining industry) have an increased risk of developing lung cancer

Some lung cancers can also cause a collection of specific symptoms which are termed syndromes. Syndromes which have been associated with lung cancer include:

• Superior Vena Cava (SVC) syndrome – The SVC is a large blood vessel that carries blood away from the head and arms to the heart. Tumours near the lung area can press against this large blood vessel causes swelling in the face and neck, chest and upper arm area

• Paraneoplastic syndromes – Some lung cancers make substances which act like hormones and can affect other tissues and organs in the body. Some paraneoplastic syndromes include:

  • Cushing Syndrome – Adrenal glands in the body may produce too much cortisol (due to cancer cells producing specific hormones), this can lead to weight gain, as well as symptoms of dizziness/tiredness and weakness

  • SIADH (Syndrome of inappropriate anti-diuretic hormone) – Cancer cells can make a hormone which encourage the kidneys to hold onto water, reducing the amount of salt in the blood. Symptoms can include; cramps and muscle weakness, tiredness, nausea and/or vomiting. In severe cases without treatment, seizures and coma may occur

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