Lung cancer not just a smoker’s disease: India saw 75,000 deaths in 2022 as non-smoker cases surge

Hyderabad: Lung cancer was traditionally thought of as a ‘smoker’s disease’. However, in the present times, many who don’t smoke are increasingly being diagnosed with lung cancer. The shifting landscape of lung cancer in India is stark. According to a WHO-IARC Globocan 2022 analysis, lung cancer accounted for over 81,700 cases and 75,000 deaths in India that year.

More cases are seen among women

Crucially, lung cancer has risen to become the sixth most common cancer among Indian women. Data from major hospitals show that a majority of women with lung cancer are diagnosed with Adenocarcinoma, a subtype of Non-Small Cell Lung Carcinoma (NSCLC).

Researchers from the Indian Council of Medical Research (ICMR) and other institutions warn that the incidence of this aggressive malignancy is rising faster in women than in men.

Here are some of the primary causes of lung cancer in non-smokers:

The air we breathe is a deadly cocktail

The primary suspect behind this distressing trend is India’s rapidly deteriorating air quality. The toxic air includes:

1. Fine particulate matter PM 2.5: This microscopic pollutant, largely a by-product of vehicle exhaust and industrial emissions, can penetrate deep into the lungs and even enter the bloodstream. Long-term exposure increases lung cancer risk by an estimated 30-50 per cent in urban, non-smoking populations.

2. Vehicular exhaust: Gases like nitrogen dioxide from heavy traffic and other components of diesel exhaust are potent carcinogens. The chronic inflammation and DNA damage they cause in lung cells can trigger the development of cancer.

3. Indoor pollution: While outdoor air pollution is a massive threat, exposure to household air pollution from burning biomass fuels (wood, cow dung) for cooking in poorly ventilated homes remains a major risk factor, disproportionately affecting women.

Radon Gas: The number one cause of lung cancer among non-smokers in USA

Radon is a colourless, odourless, inert radioactive gas that is seven times heavier than air and soluble in water.

In the USA, radon exposure is the number one cause of lung cancer among non-smokers, affecting between 10 to 15 per cent of this population.

The concentration of radon in the air depends mainly on the strength of the source and dilution factors, including uranium distribution, soil porosity and particle size, moisture content, ground cover, altitude or height above ground and weather conditions.

Building construction air can have higher radon levels

At present, there is a lack of awareness and knowledge about the association of indoor radon exposure and lung cancer in India. Radon from the ground beneath buildings is the main source of radon in indoor air.

With rapid new constructions high high-rise buildings, stone cutting and drilling going on in every city in India, it’s time to check radon levels in the basements of these buildings and specifically look at the level of Radon concentration.

Radon may enter buildings through cracks in the floor, gaps in construction, windows, drains or spaces around cables and pipes. It usually reaches higher concentrations in cellars and living spaces in direct contact with the ground, but significant concentrations can also be found above the ground floor.

The unit of measurement of radon is the Becquerel per cubic meter (Bq/m³), and the average concentration of radon in open air ranges from 5 Bq/m³ to 15 Bq/m³. It is higher in enclosed spaces, especially if they are poorly ventilated.

Radon levels can be tested by commercially available radon testers.

Low-dose CT scan (LDCT scan) and its role in early diagnosis of lung cancer

LDCT scan uses one-fifth of the dose of radiation exposure compared to a conventional CT scan of the chest. It can pick up a lung nodule (early-stage lung cancer), which can be cured by definitive surgical intervention.

According to a recent lung cancer screening study in Singapore, called the Solstice Study, it aimed to recruit 2,000 healthy individuals between 50–80 years of age with a family history of lung cancer regardless of their smoking history.

Among more than 530 patients screened via LDCT so far, nine were positive for lung cancer, and all were Stage 1 lung cancer. All these nine patients were non-smokers, and they were offered curative treatment for lung cancer.

In India, LDCT can definitely go a long way to pick up lung cancer at an early stage, provided there is a strict screening criterion to ask for LDCT.

With advancements in bronchoscopy-guided interventions, biopsy and staging can be done appropriately and definite treatment can be offered to the patient.

Dr Nishant Sinha is a Senior Consultant Respiratory Physician, Interventional Pulmonologist and Associate Clinical Director at the Department of Pulmonary Medicine, AIG Hospitals, Banjara Hills, Hyderabad