Causes and risk factors for Lung Cancer

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The main cause of lung cancer is smoking tobacco. Over 4,000 toxic substances have been identified in cigarette smoke, 60 of which are probably carcinogenic. Two of the most significant chemicals are tar and benzene (polycyclic aromatic hydrocarbons).

Risk factors


Smoking. 80–90% of lung cancers occur in people who smoke; the risk of a smoker developing lung cancer is 10 to 20 times greater than a non-smoker.

Second-hand smoker receiving smoke from a smoker

Passive smokers. Passive smokers also face an increased risk of developing lung cancer. Hence the importance of prohibiting smoking in public places.

Factory with a smoky, polluting chimney

Occupational risk factors. Like mining, insulation materials and the textile industry,...include exposure to asbestos, nickel and radon.

10% non-smokers

Non-smokers. Non-smokers can also be diagnosed with lung cancer, representing up to 10% of all cases. 



Not a hereditary. It is not a hereditary tumour but the risk may increase if your family history includes several incidences of lung cancer.


Two lungs, one of them affected

Other at-risk groups. Include individuals in a state of immunosuppression or who have chronic obstructive pulmonary disease (COPD) or pulmonary fibrosis.


What is Cancer?

General information about Cancer

Read more

Substantiated information by:

David Sánchez Lorente
Laureano Molins López-Rodó
Mari Carmen Rodríguez Mues
Noemí Reguart Aransay
Nuria Viñolas Segarra
Ramón Marrades Sicart

Published: 20 February 2018
Updated: 20 February 2018

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