Is Air Pollution Fueling lung Cancer surge In India?

Across India, doctors are sounding the alarm: lung cancer rates are climbing, and a significant portion of new cases are among people who have never smoked. While smoking remains a leading cause of lung cancer,could the nation’s worsening air pollution crisis be a major,overlooked culprit?

The Rising Tide Of Lung Cancer In India

The Numbers Paint A Stark picture. The Indian Council Of medical Research-National Cancer Registry Programme projects a surge from 1.46 million cancer cases in 2022 to 1.57 million by 2025. One in nine Indians is now expected to be diagnosed with cancer in their lifetime.

Lung cancer ranks as the second most common cancer among Indian men and is among the top five for women. Globally, it leads cancer-related deaths, underscoring the urgency of understanding its drivers in the Indian context.

A Concerning Trend: Non-Smoking Lung Cancer

Over the past two decades, medical professionals in India have noted a disturbing trend: an increase in lung cancer cases among individuals with no history of smoking.

Historically, lung cancer was strongly linked to smoking, with lower incidence rates in India compared to Western countries, reflecting differing smoking habits. Though, this pattern is shifting. A significant proportion of lung cancer patients in India today are non-smokers.

Estimates vary, but many doctors agree that up to 30% of lung cancer cases now involve individuals who have never smoked.

Did you Know? Adenocarcinoma is the most common type of lung cancer found in non-smokers reflecting a global trend.

Studies Reflect This Alarming Shift. Research from the Cancer Institute, Adyar, Chennai, highlights this change. A 2012 study found nearly 40% of lung cancer patients were non-smokers, while a 2017 study showed this figure had risen to over 55%.

Moreover, the type of cancer differs.Smokers frequently enough present with squamous cell carcinoma, while non-smokers typically develop adenocarcinoma, mirroring a global shift.

Indian patients are also presenting with cancer about a decade younger than their western counterparts, raising additional concerns. Among women, the incidence of non-smoking lung cancer is notably higher than in men.

This shift underscores the urgent need to investigate causes beyond smoking and tobacco use.

Air Pollution: An Emerging Culprit?

Krithiga Shridhar, Head of The Cancer Epidemiology Unit at the Center For chronic Disease Control, new Delhi, confirms that outdoor air pollution and particulate matter (PM) are classified as Group 1 carcinogens – meaning there’s sufficient evidence from human studies that they can cause cancer. Indoor air pollution is classified as a Group 2 carcinogen, indicating probable evidence.

India Ranks High In Pollution. According to IQAir’s 2024 World Air Quality Report, India ranks as the fifth most polluted country globally, with an annual average PM2.5 concentration of 50.6 micrograms per cubic meter – far exceeding the WHO’s recommended level of 5 and India’s National Ambient Air Quality Standards of 40.

“The Links Between Air pollution And Lung Cancer Are Well Established” says Dr. Shridhar, adding that most evidence comes from areas where pollution is lower than India. More definitive research is needed within India to confirm the direct causal relationship.

One 2022 study in the Indian Journal Of Medical Research highlights this trend and the potential role of both indoor and outdoor air pollution. Despite a decrease in tobacco use, the study notes increasing recognition of air pollution’s role in lung cancer. Nearly half of adults reported exposure to second-hand smoke at home, work, or while traveling, further complicating the picture.

Indoor Air Pollution: A Hidden Risk

Household air pollution, particularly affecting women, may also contribute. The burning of solid fuels and biomass for cooking could be a significant factor.

Even as more households switch to gas, past exposure to solid fuels may still be relevant due to lung cancer’s long latency period.

In the Northeast, where cancer rates are already high due to tobacco and alcohol, the cause of lung cancer is beginning to change, according to Ravi Kannan, director of Cachar Cancer Hospital and Research Centre, Assam. While tobacco remains a major factor, air pollution is increasingly felt, even in traditionally cleaner regions. Traditional practices, like keeping fires burning, might also contribute.

Other Factors To Consider. A study published in The Lancet Regional Health – Southeast Asia suggests occupational exposure to substances like asbestos,chromium,and arsenic,along with genetic predispositions and pre-existing lung conditions,may also contribute.

The Difficulties Of Diagnosis And Treatment

Lung cancer has one of the highest mortality rates among cancers in India, and diagnosis is often late.

Symptoms Are Non-Specific. Partha Pratim Medhi,assistant professor of radiation oncology at AIIMS Guwahati,explains that symptoms like cough,chest pain,and shortness of breath are common to many conditions,making early detection challenging. Doctors in India are also more likely to suspect tuberculosis first, perhaps delaying the correct diagnosis.

A 2022 study reveals that nearly half of patients already have advanced-stage cancer at the time of diagnosis. Of ten patients seen monthly, only one might have stage 1 or 2 cancer, while the majority are already at stages 3 or 4, according to Dr. medhi. By this point, the cancer has often spread, reducing survival rates.

Diagnostic Improvements, But Challenges Remain. While diagnostic facilities, including molecular testing, have improved, access is primarily limited to tier 1 and tier 2 cities, creating disparities in care.

Treatment options are generally available, but affordability remains a major barrier. Immunotherapy, which shows promise in other countries, is only partially accessible in India. approved drugs are frequently enough prohibitively expensive for most patients, according to Dr. Medhi.

Charting A Path Forward

Abhishek Shankar, assistant professor of radiation oncology at AIIMS, Delhi, emphasizes that air pollution should be recognized as a serious killer. With current estimates of 75,000 new lung cancer cases annually projected to reach 100,000, urgent action is needed.

more Indian-Specific Research Is Crucial. Doctors stress the need for more research into the causes of lung cancer beyond smoking. The emerging pattern of non-smoking lung cancer must be investigated to identify the specific links and causes.Air pollution is not just a risk factor for lung cancer but has been linked to other cancers and childhood leukemia.

In addition to research, strong measures to combat pollution are essential.

There is an possibility to prevent environmental pollution in the Northeast. Dr. Kannan suggests a concentrated effort from the government, NGOs, and civil society to prevent and manage future cases.

Household air pollution is declining nationally with the adoption of cleaner fuels. Though,outdoor air pollution remains a significant challenge requiring multi-sectoral solutions,says Dr. Krithiga. Acknowledging the problem and finding ways to address it is the necessary way forward.

key Facts: Lung Cancer In India