Gurugram: Around half of the patients who reported to the out-patient department (OPD) of Medanta — The Medicity over a period of 10 years and were diagnosed with lung cancer were non-smokers, according to an analysis by the doctors at the private hospital, which also suggested that the disease burden is expanding to younger populations.
Earlier, 10-20 per cent of lung cancer patients were non-smokers, the doctors who carried out the study said. They also said their analysis involving 304 patients at the hospital’s OPD between March 2012 and November 2022 indicates that the risk group for lung cancer has expanded from the dominant at-risk demographic of older adults who smoke tobacco to a relatively younger population (both smokers and non-smokers).
Nearly 20 per cent of the patients diagnosed with lung cancer were less than 50 years of age, 10 per cent were less than 40 years old, and 2.6 per cent were in their 20s, they found. The remaining patients were above 50.
The analysis is not peer-reviewed. The researchers said they will share their findings with cancer institutes and hospitals, and continue to study clinical outcomes of treatment for these patients over the years.
Doctors believe that this increase in the incidence of lung cancer among non-smokers may be linked to air pollution levels across the country, and not just Delhi-NCR.
“I am shocked by the alarming rise in lung cancer cases and its occurrence in younger individuals, non-smokers, and women. While conventional wisdom says that smoking is the main cause of lung cancer, the analysis suggests there is an increasing role of air pollution in the rising incidence. There is a need to increase awareness and promote screening for early detection,” said Dr Arvind Kumar, chairman of the Institute of Chest Surgery, Chest Onco-surgery and Lung Transplantation at the hospital.
Dr Kumar carried out the analysis with Dr Belal Bin Asaf and Dr Harsh Puri.
Asked if the patients studied were only from Delhi-NCR, Dr Kumar said: “These cases are from across the country from rural and urban areas. Pollution is not an individual problem, nor is it confined to a region. We are witnessing more cases in the north, known for hazardous levels of air pollution, but we are also seeing a rise in cases everywhere.”
With more younger people being diagnosed with lung cancer, the doctor said, there is an urgent need to increase awareness among general practitioners who may not quickly recognise the symptoms of the disease in that age group.
About 30 per cent of the lung cancer patients in the study were initially treated for tuberculosis (TB), possibly delaying their diagnosis, and consequently, life-saving interventions.
“The current trend has shown that a majority of cases are likely to be diagnosed late, when adequate treatment is not possible, resulting in high mortality due to lung cancer. A lung cancer epidemic is foreseeable in the near future,” said Dr Kumar.
The factor that helped the doctors differentiate between smokers and non-smokers was also the nature of the disease.
Half of the patients in the study were diagnosed with adenocarcinoma when cells lining the outsides of the lungs turned cancerous. This form of cancer is most commonly seen in non-smokers.
Earlier, most of the lung cancer patients had squamous carcinoma , in which cancer cells line the surface of respiratory airways, indicating an effect of smoking.
According to the US Centres for Disease Control and Prevention, around 10 per cent to 20 per cent of patients with lung cancer (20,000-40,000) are non-smokers.
Researchers say secondhand smoking, genetic mutations, exposure to radon gas and air pollution are among the key causes of it.