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Laryngeal cancer is a rare form of respiratory cancer affecting the larynx and vocal cords. The five-year survival rate in the early stages can be as high as 90%, but drastically drops to about 30% in the later stages. Addressing the current lack of epidemiological information will help healthcare professionals to understand the current disease burden of laryngeal cancer and better rationalise treatment and resource allocation.

The Chinese University of Hong Kong (CUHK)’s Faculty of Medicine (CU Medicine) has collaborated with the Association of Pacific Rim Universities (APRU) to analyse the global distribution, risk factors and epidemiological trends of laryngeal cancer. These novel results showed that the incidence of laryngeal cancer is related to different places’ per capita GDP, Human Development Index (HDI), and levels of unhealthy lifestyle habits and exposure to metabolic risk factors. The incidence and mortality rates are generally higher in middle- and high-income countries and regions. Crucially, researchers highlighted that despite the decline in the global incidence of laryngeal cancer over the past decade, both the incidence and mortality rates among women in certain regions have increased. The research team urgently calls for further exploration of the reasons for the increased burden of laryngeal cancer in women. The details of this research have been published in a top international medical journal, the International Journal of Surgery.

Laryngeal cancer linked to numerous risk factors, with higher burden in middle- and high-income countries

Laryngeal cancer primarily affects individuals aged between 45 and 70, with a significant gender disparity: the ratio of male to female patients is 13:1. Risk factors include smoking and alcohol consumption—in particular, the tar and carcinogens contained in cigarettes can irritate the throat, causing mucosal hyperplasia, which may then develop into leukoplakia and carcinogenesis. Due to global efforts in recent years to encourage smoking reduction and prevent excessive drinking, the overall incidence and mortality rates of laryngeal cancer have been declining, especially among men. However, regional disparities in laryngeal cancer incidence and mortality rates continue to persist due to varying levels of access to medical care.

This research sought to estimate the disease burden and distribution of laryngeal cancer around the world, with a focus on identifying high-risk populations. The research team collected cancer incidence data and the prevalence of different laryngeal cancer risk factors via several sources, including the World Health Organization Global Cancer Observatory, and the Cancer Incidence in Five Continents and Global Disease Burden studies. Researchers found that the disease burden caused by laryngeal cancer differs by region, with the Caribbean having the highest incidence and mortality rates globally (see Tables 1 and 2 in the appendix for detailed data). Laryngeal cancer was associated with smoking, drinking, unhealthy diet, lack of exercise, obesity, hypertension, diabetes and dyslipidemia, with higher incidence and mortality rates observed among people exposed to these risk factors.

Rise in female laryngeal cancer rates in some regions demands further analysis

Although the global incidence rate of laryngeal cancer has been generally declining over the past decade, there are indications of an increase in the incidence among women in certain areas. The Average Annual Percentage Change (AAPC[1]) in female incidence rates has significantly increased, with Japan, Switzerland and the Czech Republic showing the most notable rises (see Table 3 in the appendix for detailed data).

Dr Jason Huang Junjie, the first author of the study and Research Assistant Professor from The Jockey Club School of Public Health and Primary Care at CU Medicine, stated, “The incidence of laryngeal cancer varies regionally, which may be related to local diagnostic and treatment levels, environmental lifestyles, and policies controlling smoking and alcohol consumption. Our research provides the latest and most comprehensive evidence on the global distribution, risk factors and epidemiological trends of laryngeal cancer. Policymakers in various regions should implement targeted, evidence-based prevention strategies, such as smoking cessation and alcohol control measures, to manage the risk factors.”

Professor Martin Wong Chi-sang, the senior corresponding author of the study, Professor of The Jockey Club School of Public Health and Primary Care at CU Medicine, added, “In recent years, the overall incidence of laryngeal cancer has been declining, but the rising incidence among women in certain areas is concerning. The reasons behind this trend are unclear and may be related to increasing peripheral environmental factors, lifestyle habits and metabolic risk factors. The medical community should further explore the causes of these epidemiological changes to provide important insights for the prevention and treatment of laryngeal cancer.”

This study was conducted in collaboration with Professor Mellissa Withers, Director of the APRU Global Health Program and a faculty member at the Keck School of Medicine within the University of Southern California.

Study details can be found at: https://doi.org/10.1097/JS9.0000000000000902

[1] AAPC is a measure of the overall changes in cancer incidence over a specific period. For example, if the incidence AAPC of a certain cancer in a country is five for the past 10 years, it means that the incidence in that country increased by 5% on average each year over the 10-year period.