This World Cancer Awareness Month, let’s take a close look at the link between…
Decoding the link between lung cancer and non-smokers, this World Cancer Awareness Month
Lung cancer is one of the commonest cancers in the world. It accounts for more cancer deaths than any other cancer. It is increasingly being recognized in India and in recent years has surpassed the earlier commonest form of cancer, that of oropharynx, to become the commonest malignancy in males. The major risk factor for developing lung cancer is tobacco use and this disease is often viewed solely as a smoker’s disease. However, a significant number of patients with lung cancer have no history of smoking. According to the data available, as many as 20 % of the lung cancer patients in the Western countries and almost 50 % of the lung cancer patients in India are non-smokers. In fact, it is so common in non-smokers also that if lung cancer in non-smokers had its own separate category, it would rank among the top 10 fatal cancers.
Lung cancer in non-smokers is a different disease in many ways. It usually presents as a more advanced disease, at an earlier age, say around 50 years. It has a gender predilection, that two-thirds of the nonsmokers who get lung cancer are women. It is especially seen in patients with higher waist circumference and those suffering with metabolic syndrome. A lot of research in the past decade or so has elucidated various other factors that cause lung cancer.
Air pollution - WHO (World Health Organization) has labeled air pollution as the single most important environmental health hazard. Both indoor pollutants like the fumes from cooking oil following stir-frying, deep-frying, and pan-frying, which involve heating oil to high temperatures and the smoke from a coal stove as well as outdoor pollutants like industrial and vehicular smoke can trigger off lung cancer.
Radon gas - The leading cause of lung cancer in non- smokers is exposure to radon gas. Radon occurs naturally outdoors in harmless amounts, but sometimes becomes concentrated in homes built on soil with natural uranium deposits. Studies have found that the risk of lung cancer is higher in those who have lived for many years in a radon-contaminated house.
Occupational exposure - It is known to occur in individuals who are chronically exposed to chemicals like asbestos, arsenic, silica and some other chemicals.
Second hand smoke - Also called passive smoking, it can be equally dangerous. It refers to the smoke inhaled by people standing in close proximity of the people who are smoking. Almost two thirds of the smoke is liberated by a smoker in the air around him. These often grow in the outer regions of the lungs and can be present for a long time before symptoms occur. Symptoms such as shortness of breath, fatigue, or symptoms due to spread of the cancer to other regions of the body (such as bone pain) may be more common. These cancers are mostly of the adenocarcinoma variety and are known to have certain specific genetic mutations, which actually turn out to be beneficial for the patient, as then certain therapies targeting these mutated genes can be used for its treatment. Therefore anyone being diagnosed with lung cancer must undergo genetic testing for these genes. Lung cancer in non-smokers is often diagnosed at a late stage, being first attributed to a respiratory infection or even allergies. Still, some studies suggest that the overall survival is better in non-smokers. This difference is most apparent for those who are diagnosed at an early stage of the disease. Female non-smokers have a better prognosis in general than male non-smokers with lung cancer. A healthy diet comprising lots of fruits and vegetables may help reduce the risk of and protect against lung cancer. But any positive effects of fruits and vegetables on lung cancer risk would be much less than the increased risk from smoking.
smoke Second hand refers to the smoke inhaled by people standing in close proximity of the people who are smoking.