Lung Cancer Among Non-Smokers – India has seen an alarming rise in lung cancer cases among non-smokers in recent years. Expert explains the reasons behind it.
In India, lung cancer is estimated to account for 5.9 per cent of all cancer diseases and 8.1 per cent of all cancer-related deaths. As per the Population-based Cancer Registries (PBCRs), lung cancer is the leading type of cancer among Indian men. Tobacco use is known to be the main cause of lung cancer. However, several research studies have highlighted an alarming rise in lung cancer cases among non-smokers in the country in recent years. What is causing lung cancer among non-smokers?
To understand the reasons behind the rise in lung cancer among non-smokers, we connected with Dr T Sujit, Radiation Oncologist, American Oncology Institute, Coimbatore. Excerpts follow:
What Are The Factors That Increase Risk Of Lung Cancer Cases Among Non-Smokers?
Risk factors for lung cancer among non-smokers include secondhand tobacco smoke, air pollution (industrial and vehicle emissions ), radon gas ( found naturally in air ),asbestos and certain inherited or acquired genetic changes.
A study, published in the Journal of Clinical Oncology, linked use of vitamin B6 and B12 from individual supplement sources with increased risk of lung cancer risk in men. Should we stop taking these supplements?
Around 2015-2017, there was a renewed interest in Vit B12 and its functions and deficiency disorders. There were several papers which concluded that there was an association of high Vit B12 levels with various cancers. This was seen in men and notably in smokers. However, none of the studies could explain the relationship between the high Vit B12 levels and cancer- was the high B12 causing it or was it a result of the cancer? There are quite few disorders that can cause high levels of Vit B12 too like diabetes, kidney dysfunction, liver disorders, auto-immune diseases, etc. A few papers from Asia and France have stated that there is no significant association between raised Vit B12 and cancer when these diseases/conditions are accounted for in the trial subjects. Moreover, in articles claiming an association between high Vit B12 levels and cancer, there was no hypothesis as to how the circulating Vit B12 levels were raised, although one paper suggested that it could be due to the rapid cell proliferation of malignant cells. Till date, there is no conclusive evidence that intake of large amounts of Vit B12 or B6 causes cancer. Excess intake of any supplement can be harmful. In prescribed doses, supplements tend to do no harm.
What Are The Reasons Behind High Prevalence Of Non-Small Cell Lung Cancers In India?
The commonest lung cancer types in the world over, is non-small cell lung cancer (NSCLC). There are two common types of NSCLC – squamous cell carcinoma and adenocarcinoma. Of these the squamous cell type is slightly less prevalent than the adenocarcinoma type. The adenocarcinoma variety of lung cancer has a very strong association with tobacco smoking.
Most Common Types Of Lung Cancers In India
A study identified adenocarcinoma (ADC), squamous cell carcinoma and small cell lung cancer as the most common types of lung cancers diagnosed in India, contributing 34 per cent, 28.6 per cent and 16.1 per cent cases respectively. While smokers are usually affected with small cell lung cancers, non-small cell lung cancers are seen in both smokers and non-smokers alike. As many as 85 per cent of lung cancers cases in India are non-small cell lung cancers. Adenocarcinoma cancer are found to be more common among non-smokers.
The same study, which covered lung cancer patients for a 10-year period, also revealed that cases of lung cancer are rising among females in India.
Misdiagnosis is the major problem in detecting lung cancer at an early stage in the country. This is because the symptoms are of lung cancer are often mistaken as those of pulmonary tuberculosis (TB). This leads to misdiagnosis and delay in detection. Home
