Lung cancer cases are rising among women who have never smoked, particularly lung adenocarcinoma, the most common type of lung cancer in non-smokers. Studies show that nearly 60% of lung cancer cases in women are adenocarcinomas, compared to 45% in men. This increase has been linked to a combination of genetic, environmental, and hormonal factors that make women more vulnerable to the disease.
A key factor in lung cancer among non-smokers is genetic mutations, especially in the EGFR gene, which plays a critical role in cell growth and division. Mutations in this gene are found in about 50% of lung adenocarcinomas in non-smoking Asian women and 19% in non-smoking Western women, compared to just 10-20% in men. These mutations drive uncontrolled cell growth and tumor formation. Recent studies suggest that exposure to air pollution, which triggers EGFR mutations, may be exacerbating the prevalence of these mutations. Furthermore, mutations in other genes like ALK, ROS1, and TP53 are also linked to lung cancer development in non-smokers. Interestingly, mutations in TP53, a gene that suppresses tumor formation, appear more frequently in women than men and may interact with estrogen, further increasing cancer risk.
Air pollution, particularly tiny particles known as PM2.5, is another significant factor. These particles, which are smaller than 2.5 micrometers, have been shown to contribute to genetic mutations and lung cancer. As urbanization increases, exposure to PM2.5 has become more prevalent, particularly in women. Studies indicate that women’s smaller lung size and narrower airways make them more susceptible to the harmful effects of these pollutants, allowing more particles to become trapped in the lungs. In addition, estrogen has been found to amplify inflammatory responses to pollutants, making lung tissue more vulnerable to damage and cancerous growth.
Hormonal fluctuations also seem to play a role in lung cancer development among women. Oestrogen receptors are present in lung tissue, and experimental studies suggest that oestrogen may promote tumor growth. Women who undergo hormone replacement therapy (HRT) appear to have a lower risk of lung cancer, suggesting that natural estrogen cycles may offer some protection. However, these protective effects may diminish with age or other contributing factors, such as chronic inflammation.
Chronic inflammation is another important factor in the rise of lung cancer among non-smoking women. Women are more prone to autoimmune diseases, such as rheumatoid arthritis and lupus, which cause prolonged inflammation and can increase the risk of cancer. Inflammatory molecules like interleukin-6 and tumor necrosis factor-alpha may promote cancer by helping tumor cells survive and spread. Autoimmune diseases, which are increasing globally, contribute to this chronic inflammation. Environmental changes, diet, and shifts in gut microbiomes likely play a role in the rising prevalence of autoimmune conditions.
Moreover, the growing exposure to household chemicals, industrial pollutants, and work-related toxins further worsens immune system imbalances, heightening the risk of lung cancer in women. Women working in industries like textiles, beauty salons, or hospitals are often exposed to harmful chemicals that can damage their lungs. In rapidly urbanizing areas, women living in high-traffic and industrial zones are particularly vulnerable to air pollution, further increasing their risk of developing lung cancer.
The rising incidence of lung cancer in women is the result of a complex interplay of genetic, hormonal, environmental, and immune factors. While women may be biologically predisposed to certain genetic mutations that increase their susceptibility to lung cancer, factors like rising pollution, hormonal fluctuations, and autoimmune conditions are amplifying these risks. Additionally, studies suggest that viruses like HPV may also contribute to lung cancer in women. Ongoing research into the roles of these various factors is crucial for developing early detection methods, more effective treatments, and preventive strategies to reduce the burden of lung cancer in women.
