Chinese Medical Journal article sheds light on the global lifetime risk of lung cancer

Lung cancer remains the most prevalent form of cancer, with nearly 2.2 million cases and 1.8 million deaths globally. While smoking is the major risk factor, passive smoking, air pollution, and exposure to industrial carcinogens and cooking fumes also contribute to its development. Importantly, the incidence and mortality rates of lung cancer differ by various factors, such as country and sex, owing to differences in economic growth and smoking habits.

In addition to incidence and mortality rates, the lifetime risk also provides detailed insights into the condition. This measure captures the cumulative probability of being diagnosed with or dying from cancer over an individual’s remaining lifespan while accounting for other potential competing causes of mortality. Although many studies have estimated the global lifetime risk of various types of cancer, few have specifically focused on the risk of developing or dying from lung cancer.

Against this backdrop, a research group from the National Cancer Center, Chinese Academy of Medical Sciences and Peking Union Medical College, China, investigated the lifetime risk of lung cancer across 185 countries by age, sex, and human development index (HDI) in 2022. The study was published in the Chinese Medical Journal on November 13, 2024. The authors say, “Lifetime risk provides an intuitive assessment of lung cancer risk exposure in a population, and this index may help long-term cancer prevention and control planning in the health system, considering that it is the deadliest form of cancer.”

To this end, researchers used the Global Cancer Observatory 2022 database to extract incidence and mortality of lung cancer across different sexes and age groups. They obtained the population and all-cause mortality data from the United Nations. Furthermore, they selected 20 geographical areas, including Eastern Asia and Western Europe et al, and categorized countries within these areas based on their HDI. Using these inputs, researchers applied the adjustment for multiple primary cancers method—accounting for competing causes of death and multiple lung cancer diagnoses—to calculate the lifetime risk of lung cancer.

Researchers found that in 2022, the global lifetime risk of developing lung cancer was 3.49%, which is 1 in 28 people. Similarly, the risk of mortality from lung cancer was 2.69%, which is 1 in 37 people.

Interestingly, the lifetime risk of lung cancer was high in countries with high and very high HDIs, like French New Caledonia and Canada, with the risk of lung cancer development over 8.12% and the risk of death approximately 2.69%. In contrast, countries with medium to low HDIs, like Niger and Angola, had a relatively low risk of lung cancer, with the risk of developing or dying with lung cancer nearly 0.1%. This disparity is attributed to long life expectancy and high awareness of health check-ups in high-HDI countries, while low-HDI countries report reduced risk due to shorter lifespans and limited resources for cancer detection.

Before the age of 40, the probability of developing lung cancer and dying from it is very low. However, after the age of 40, this risk drastically increases, marking a critical period for executing cancer prevention plans and expanding screening efforts. Surprisingly, later in life, the residual risk of lung cancer decreases with age. But, by the age of 70, individuals who have not been affected by lung cancer still have a high risk of developing and dying from lung cancer at 2.00% and 1.71%, respectively. The authors note, “This may be because the accumulation of exposure to risk factors related to lung cancer occurrence takes a long time. The decline of risk with age can be attributed, at least in part, to the presence of other age-related diseases that pose competing risks.”

Consistent with previous studies, men had a 57% higher probability of developing lung cancer, and an 85% higher probability of mortality compared to women, mainly due to smoking. However, in a few countries like Denmark, Iceland, Sweden, and Peru, women had a slightly higher lifetime risk of lung cancer than men.

Overall, the study establishes a scientific foundation for addressing the growing burden of lung cancer at global, regional, and national levels. The authors emphasizes, “The results revealed the complete measurement of lifetime probability, offering crucial data for planning healthcare systems worldwide and implementing targeted interventions for lung cancer control in diverse populations.”

Hopefully, this study will prompt nations to adopt a strategic approach toward screening, diagnosing, treating, and preventing lung cancer, ultimately reducing its global burden and saving lives.

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Reference

DOI: 10.1097/CM9.0000000000003368