Lung Cancer (Adenocarcinoma of the Lung)

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What is Lung Cancer?

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Lung cancers are tumours arising from cells lining the airways of the respiratory system. Adenocarcinoma of the lung is one of the main types of lung cancers. Adenocarcinoma of the lung arises from the secretory (glandular) cells located in the epithelium lining the bronchi.

Who gets Lung Cancer?

Lung cancer is common. One in every 28 Australians will develop lung cancer during their lifetime. Lung cancer is also deadly: it is the commonest cause of cancer death in Australia, accounting for around 23% of male and 15% of female cancer deaths. Lung cancer is more than twice as common in men as in women. Geographically, the tumour is found worldwide, but it is especially common in countries with a high tobacco consumption. Adenocarcinoma of the lung is the commonest type of lung cancer, accounting for 32% of all cases of lung cancer.

Predisposing Factors

Cigarette smoking is the main predisposing factor. In recent years, it has been recognised that passive smoking (e.g. from a first degree relative in a house of smokers) can also put people at risk. Generally, the risk increases with the number of cigarettes smoked. The link between cigarette smoking and adenocarcinoma is weaker than the link between smoking and other types of lung cancer, but is still the most significant risk factor identified.

Exposure to asbestos increases the risk of developing this tumour. The combination of asbestos exposure plus cigarette smoking is particularly harmful. Other occupational exposures such as exposure to metals including arsenic, chromium and nickel can also increase risk.

Some studies have suggested that diet can play a role in lung cancer risk. Though it is not known how it works, diets high in fruits and vegetables seem to decrease risk.

Radiation exposure damages the DNA material within the cells and can also cause lung cancer. Radon (a radioactive gas) exposure from our normal surrounding environment, if higher than normal, can predispose to lung cancer. This evidence is mainly based upon population studies which show that people living in areas with a high radon content are prone to increased incidences of a variety of cancers.

Progression

Adenocarcinoma of the Lung cancer Adenocarcinomas tend to be slow-growing. Spread of the tumour can occur by the lymphatic vessels to lymph nodes located within the lung, mediastinum and thorax. If spread by the blood stream, it can lead to deposits of tumour in the liver, opposite lung, bone and brain.