Lung cancer tops in east Asia

Lung cancer incidence and mortality over the past decade had an overall increasing trend in females but a decreasing trend in males, researchers from the Chinese University of Hong Kong and the Association of Pacific Rim Universities have found.

With a survival rate much lower than that of other major cancers by five years, lung cancer accounted for around one-fifth of all global cancer deaths in 2020.

By looking into the lung cancer data retrieved from international databases such as the Global Cancer Observatory, the World Health Organization mortality database and WHO Global Health Observatory data repository, researchers found significant differences in sex for lung cancer incidence and mortality in the past decade, with many countries and regions showing declining trends in males and rising trends in females.

Italy showed the highest decline of -3.5 for the average annual percentage change in the incidence for males.

Australia, however, had the highest increase of 1.7 in the incidence for females.

For mortality, the Netherlands reported the greatest decrease of -3.3 in males, while Spain had the highest increase of 4 in females.

A similar trend was observed in Hong Kong as well. Between 2010 and 2019, lung cancer incidence increased in females of all ages by 1.2 while showing a decrease in males by -1.1.

Incidence increase was also more evident in females aged less than 50 years than females aged 50 or above, researchers found.

While the mortality of lung cancer in Hong Kong decreased in both sexes, the decrease was less evident in females than males.

According to the Hong Kong Cancer Registry, lung cancer is the most common cancer in the SAR, accounting for 27.1 percent of all cancer deaths in 2019.

Meanwhile, researchers also found that eastern Asia has the highest incidence and mortality rate in lung cancer.

The incident rate for every 100,000 people in the region was 34.4, and it was followed by western Europe, northern America, northern Europe and southern Europe.

The mortality rate for Eastern Asia was also the highest among the top five world regions for lung cancer mortality rate. The others included western Europe, central and eastern Europe, southern Europe and western Asia.

Researchers suggested that the higher incidence and mortality rate in eastern Asia was associated with the human development index, gross domestic product figures and prevalence of smoking in society.

Huang Junjie, author of the study and post-doctoral fellow from The Jockey Club School of Public Health and Primary Care at CU Medicine, said the reasons behind the age, sex and regional differences were all related to tobacco consumption.

"For example, there is a study showing that the smoking cessation rate was significantly higher in older males than females. But it is notable that second-hand smoke, indoor air pollution and exposure to chemicals play important roles in the variations too," he said.