Lung cancer is a neoplasm that originates in lung tissue. It is the most frequent carcinoma in the world, affecting men and women equally. The main risk factor is tobacco, which is responsible for 80% of the cases. Early diagnosis of lung cancer is the main condition for its successful treatment.
Lung cancer accounts for almost 12% of all carcinomas diagnosed worldwide. The main cause of the development of lung cancer is smoking. It is estimated that around 80% of cases are caused by smoking and many of the remainder by exposure to tobacco smoke.
Smoking is undoubtedly the main risk factor for lung cancer, although others have also been identified that may contribute:
- Time and number of cigarettes. The risk of lung cancer increases the more and longer cigarettes are smoked.
- Passive exposure to tobacco smoke.
- Exposure to radon, a radioactive gas that accumulates inside some homes and workplaces. It is estimated to be responsible for between 3-14% of lung cancer cases.
- Exposure to asbestos
- Environmental contamination. Some studies suggest that pollution in large cities may increase the risk of lung cancer.
Although the main associated risk factors are environmental, tobacco being the most important, it has been shown that there is a hereditary component, although this is not entirely clear. Among the GWAS studies that have been carried out to date, one study with more than 85,000 cases and almost 30,000 controls stands out. The loci that showed association have highlighted the heterogeneity of the different histological subtypes of lung cancer. Among the genes identified, RNASET2, SECISBP2L and NRG1 stand out, among others associated with lung function. The researchers estimate that this study explains 12.3% of the heritability of lung cancer and that further studies are needed to elucidate the role of genetics in this disease.
In the early stages, lung cancer does not usually show symptoms. These appear when the cancer is more advanced, making its prognosis poor. The most characteristic signs and symptoms are:
- Persistent cough with blood.
- Shortness of breath.
- Chest pain.
- Weight loss without apparent cause.
- Bone and joint pain.
- Inflammation in the neck and face.
Lung cancer is the leading cause of death in the world. Although it is not totally preventable, its risk can be effectively reduced by a series of measures.
- Avoid exposure to tobacco. Not smoking and avoiding exposure to tobacco smoke is the most effective measure to reduce the risk of lung cancer.
- Avoid exposure to radon or asbestos, chemicals directly related to lung cancer.
- Healthy lifestyle, with a balanced diet rich in fruits and vegetables and regular physical exercise.
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Mao Y, Yang D, He J, Krasna MJ. Epidemiology of Lung Cancer. Surg Oncol Clin N Am. 2016 Jul;25(3):439-45.