Rising Lung Cancer Rates Among Non-Smoking Women
Research shows a significant rise in lung cancer cases among women who never smoked. Find out why and what factors are involved.
Why Lung Cancer Rates Are Rising Among Non-Smoking Women
New research from the World Health Organization (WHO) Cancer Institute reveals that lung cancer cases are increasing among individuals who have never smoked, particularly among women.
Published in The Lancet Respiratory Medicine, the findings indicate that adenocarcinoma, a type of lung cancer common among non-smokers, now accounts for nearly 60% of lung cancer cases in women, compared to 45% in men.
Globally, around 2.5 million new cases of lung cancer were diagnosed in 2022—a rise of 300,000 cases since 2020.
Key Factors Driving the Surge
Environmental factors, particularly air pollution, genetic changes, and immune system anomalies, are all contributing to the increased risk of lung cancer among non-smokers.
One significant factor is genetic mutations, especially in the EGFR gene, which provides instructions for producing proteins involved in cell growth and division. Mutations in this gene lead to uncontrolled cell division and cancer development. Among Asian women who are non-smokers, EGFR mutations account for 50% of cases, compared to 19% in Western women and just 10-20% in non-smoking men in these regions.
Recent advancements in genetic testing have made it easier to detect these mutations. Moreover, air pollution is known to contribute to EGFR gene mutations, further exacerbating the risk.
Other genetic mutations linked to lung cancer include alterations in the ALK and ROS1 genes, which are responsible for about 5% of lung cancer cases in non-smokers. These mutations are especially prevalent among younger, non-smoking women, particularly in East Asia. Fortunately, enhanced screening programs in countries such as those in East Asia have made it easier to detect these genetic changes.
Mutations in the TP53 gene, which normally acts as a tumor suppressor, are also more commonly found in non-smoking women. TP53 mutations lead to uncontrolled cell growth, and estrogen hormones may interact with these mutated genes, further raising the risk of lung cancer in women.
Another notable gene, KRAS, is usually associated with smoking-related lung cancers but is also seen in non-smokers, particularly women, contributing to cancer development.
Research suggests that airborne particulate matter, particularly PM2.5 (particles smaller than 2.5 micrometers), is a key driver of these genetic changes in women. As PM2.5 levels continue to rise in many cities, these particles are increasingly linked to lung cancer, as well as other cancers in women.
In addition to genetic mutations, hormonal changes also play a role in the development of lung cancer among women.
Immune System and Chronic Inflammation
Beyond genetic factors and hormones, chronic inflammation is also believed to contribute to the rise of lung cancer among women who have never smoked. Women are more likely than men to experience autoimmune conditions, in which the immune system attacks healthy cells. This can lead to tissue damage, DNA mutations, and abnormal cell growth, all of which increase cancer risk.
Globally, autoimmune diseases have been on the rise, likely due to environmental changes, dietary shifts, and alterations in gut microbiota, which plays a crucial role in our overall health. Additionally, factors such as air pollution, household chemicals, and workplace-related exposures further exacerbate immune system dysfunction, heightening the likelihood of developing cancer.
Long-term exposure to air pollution has been identified as a significant risk factor for lung cancer, with recent evidence showing that women are more susceptible than men.
Biological Differences and Air Pollution
Research suggests that women’s lung structure and function make them more vulnerable to the harmful effects of environmental pollution. Women typically have smaller lungs with narrower airways, which makes it easier for fine particles like PM2.5 to become trapped in their lungs.
While men are often exposed to environmental pollutants due to industrial work, women tend to spend more time indoors, where they are exposed to toxic smoke from cooking and heating. Air pollution from sources such as wood, coal, and kerosene further increases the risk of lung cancer for women.
Women working in industries such as textiles, salons, and healthcare are also at a higher risk due to exposure to hazardous chemicals that can damage their lungs.
In rapidly expanding cities, women are more likely to live in areas with heavy vehicle traffic and industrial pollution, exacerbating their exposure to harmful air particles.
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