Can you develop lung cancer without touching a single cigarette? Yes, and the diagnosis of Pope Leo XIV reminds us of this. Several factors, such as pollution, radon or certain genetic predispositions, can also be involved.
Lung cancer: why are non-smokers so affected?
Too often, we spontaneously associate lung cancer with cigarettes. Except that other elements may come into play, “such as genetic and environmental factors”,
explains Dr. Gérald Kierzek, emergency physician and medical director of True Medical. Therefore, not all lung tumors are alike: some have specific genetic mutations.
A study conducted in 2026 by researchers at the University of Miami recorded a significant proportion of targetable mutations in young adults.
“This study of more than 14,000 patients with non-small cell lung cancer showed that nearly 58% of young adults had targetable genetic mutations, such as EGFR, ALK or ROS1, compared to 45% of patients aged 55 and older. These mutations may make tumors more sensitive to targeted therapies,” explains the medical expert.
Each person’s hereditary predispositions also count, particularly when one or more family members have already been affected by this cancer. “Certain predisposition genes, such as ATM, could increase the risk of lung cancer by 36 times in certain situations,” specifies the doctor.
Radon, pollution, work: factors not to be neglected
Tobacco is the primary risk factor for lung cancer, but not the only one. The National Cancer Institute cites, in France, the KBP 2020 study: non-smokers represented just over 12% of patients with non-small cell lung cancer.
Radon, a colorless and odorless radioactive gas that can accumulate in poorly ventilated homes or workplaces, is also problematic: “iIt even constitutes the main environmental cause of lung cancer in non-smokers according to the World Health Organization (WHO). However, any prolonged exposure to this gas would increase the risk by approximately 16% for each increase of 100 Bq/m³ in the concentration in the air. warns Dr. Gérald Kierzek.
Fine particles present in the air (such as PM2.5) are also associated with an increased risk of lung cancer in non-smokers.“particularly in East Asia”, underlines the medical director.
Finally, certain professions are more at risk than others.
“Certain occupational exposures are also recognized as carcinogenic, notably asbestos, crystalline silica and diesel engine exhaust, including at low doses,” recalls the specialist.
Finally, cooking fumes could play a role in certain populations. “In Asian homes, frying at high temperatures produces carcinogenic compounds. Studies have established a relationship between the cumulative frequency of these practices and the risk of adenocarcinoma in non-smoking women,” says the doctor.
To better understand the risk factors for lung cancer, we must therefore look at all exposures, not just smoking or non-smoking status.
Lung cancer: why are women so affected?
If the case of the sovereign pontiff raises many questions, it is also because he does not represent the “typical” profile of people with lung cancer. Women are also largely affected by this disease.
“Non-smoking women and East Asian populations are particularly affected. In Asian women who do not smoke, the detection rate of lung cancer would even be comparable to that observed in Asian men who smoke,” says Dr Gérald Kierzek.
In the United States, approximately one in five women diagnosed with lung cancer have never smoked, according to a 2021 study.
It should also be emphasized that lung cancer in non-smokers presents different biological characteristics from that of smokers.
“We observe in particular a predominance of adenocarcinomas and certain genetic mutations that can be targeted by treatments”, notes the specialist.
What symptoms should alert you, even when you don’t smoke?
At first, lung cancer is often silent. However, the earlier it is detected, the better the prognosis for survival.
“There are certain signs that should alert you, even if you have never smoked,” warns Dr. Gérald Kierzek.
A new cough that persists or worsens should therefore prompt you to consult a doctor. The presence of blood in the sputum (or rust-colored sputum), even in small quantities, also requires medical advice.
“Finally, chest pain that gets worse when breathing deeply, coughing or laughing should also be taken into account. The same goes for unusual shortness of breath, new wheezing or persistent hoarseness,”
explains the doctor.
“Other more general signs may also appear, such as unexplained weight loss, decreased appetite or persistent fatigue. Respiratory infections, including bronchitis or pneumonia, which do not heal or which come back regularly, may also be revealing,” underlines the medical director of True Medical.
What about when the disease has spread to other organs?
In this case, bone pain, headaches or swelling of the face or neck may occur.
“When the cancer has spread to other parts of the body, other symptoms may occur, including bone pain, headache, or swelling of the face or neck,” specifies Dr Gérald Kierzek.
These symptoms do not necessarily mean that it is cancer. But when they persist, worsen or remain unexplained, it is better to consult. Moreover, it is often during a simple medical examination that lung cancer is discovered in non-smokers – not included in standard screening programs.
“The diagnosis is often based on the identification of symptoms or on the incidental discovery of an abnormality during an examination carried out for another reason”, confirms Dr Gérald Kierzek.
A chest CT scan may then be prescribed to detect any abnormalities in the lungs and guide the diagnosis.