The Rise of Lung Cancer Among Never-smokers
Take a deep breath, recent NIH studies show that 1 in 4 lung cancer cases worldwide arise in people who never smoked, experts give a lowdown on contributing factors
For decades, lung cancer was labelled as a smoker's disease. It was a diagnosis almost synonymous with cigarettes, tobacco and years of lighting up. However, recent studies by National Institutes of Health (NIH) have revealed that 1 in 4 lung cancer cases worldwide arise in people who never smoked. Yes, you read that right! People who have never smoked a cigarette, never chewed tobacco, and often led otherwise healthy lives, have been diagnosed with lung cancer.
Every year, over 1 million people die due to lung cancer across the world. In India, every year nearly 60,000 people die due to lung cancer. According to a study published in the Indian Journal of Medical Research, the prevalence of lung cancer cases is the highest in India’s North-East region. “Though smoking is still the biggest risk factor for lung cancer, there is a noticeable increase in cases among never-smokers,” says Dr Arjun Bhatnagar, Consultant, Pulmonary Medicine at Regency Health.
Dr. Arjun explains that currently, nearly 15% to 20% of lung cancer patients worldwide have never smoked. Among women and several Asian populations, this proportion is even higher. While advances in diagnostic techniques have improved detection, he says the rising numbers are also linked to a combination of genetic predisposition, environmental exposures and changing lifestyles. Together, these findings underscore an important shift: smoking is no longer the sole driver of lung cancer.
BagFul of Triggers
If cigarettes are no longer the only culprit then what else could it be? Experts say there is no single answer. Instead, lung cancer in never-smokers (aka non-smokers) is believed to arise from a complex interplay of genetic predisposition and environmental exposures.
Dr Arjun says, “Strong scientific evidence links long-term exposure to air pollution, passive smoking, indoor smoke from biomass fuels, radon exposure, and occupational hazards such as asbestos, silica, and diesel exhaust with an increased risk.” While each factor alone may not explain every case, together they paint a broader picture of a disease that extends far beyond tobacco use.
Dr Vikas T. Talreja, Senior Consultant, Medical Oncology at Regency Health explains, “Lung cancer in people who have never smoked is often different from the type seen in smokers.” Dr. Vikas further explains that in smokers, lung cancer usually develops after years of tobacco smoke causing cumulative damage to the DNA. In contrast, among non-smokers, the disease is more often driven by specific genetic alterations within the cancer cells rather than widespread damage from smoking.
He says these cancers tend to behave differently and, when the underlying genetic mutation is identified, often respond well to targeted therapies designed to attack those specific changes.
The Risk Factors
Individuals with a family history of lung cancer, prolonged exposure to second-hand smoke, air pollution or indoor biomass fuel, as well as those working in environments with asbestos, silica or radon exposure, also face an elevated risk.
Dr. Vikas seconds this, “We do see a higher proportion of women and relatively younger patients among non-smokers diagnosed with lung cancer.” He explains that exact reasons are yet being studied. However, factors such as genetic susceptibility, hormonal influences, indoor air pollution, second-hand smoke, and environmental exposures all play a role.
Lung cancer rarely arrives with a bang. It often slips in quietly. A cough that refuses to leave, breathlessness after routine activities, persistent
chest pain, coughing up blood, unexplained weight loss, recurring chest infections, hoarseness of voice and lingering fatigue are among the warning signs that should never be brushed aside.
“Persistent cough lasting more than three weeks, unexplained breathlessness, chest pain, recurrent respiratory infections, coughing up blood, unexplained weight loss, fatigue, or persistent hoarseness should never be ignored.” says Dr. Arjun.
Misconceptions Galore
Yet, the danger lies in mistaking these symptoms for allergies, asthma, acidity or a stubborn viral infection, especially in someone who has never smoked. Dr. Arjun says that respiratory symptoms should never be ignored if they persist despite treatment, keep coming back, or are accompanied by warning signs such as unexplained weight loss, coughing up blood, persistent chest pain or worsening breathlessness.
He explains that while a chest X-ray is often the first step in evaluation, a CT scan may be needed if symptoms remain unexplained or there is a strong suspicion of lung cancer. Early imaging, he adds, can help detect the disease sooner, when treatment is more likely to be effective.
The Risk Continues
Point being, for years, the conversation around lung cancer began and ended with tobacco. Today, science is urging us to turn the page. While smoking remains the leading cause, it is no longer the only story. Genetics, environmental exposures and advances in molecular research are reshaping how doctors understand, diagnose and treat the disease.
So, as science uncovers a distinct form of lung cancer in non-smokers, the greatest risk may no longer be tobacco alone, but delayed suspicion and delayed cure!