Cancer Incidence Continues to Rise: 1 in 5 Men, 1 in 6 Women

Roxanne Nelson, BSN, RN

September 14, 2018

In 2018, an estimated 18.1 million new cases cancer will be diagnosed globally, and 9.6 million will die from the disease, according to the latest report from the International Agency for Research on Cancer (IARC).

One in 5 men and one in 6 women worldwide will develop cancer during their lifetime, and one in 8 men and one in 11 women will die from cancer.

Cancer incidence and mortality are rapidly growing worldwide, the report notes.

"The increasing cancer burden is due to several factors, including population growth and ageing as well as the changing prevalence of certain causes of cancer linked to social and economic development," the IARC commented in a statement. "This is particularly true in rapidly growing economies, where a shift is observed from cancers related to poverty and infections to cancers associated with lifestyles more typical of industrialized countries."

Worldwide, the total number of people who are alive within 5 years of a cancer diagnosis (the 5-year prevalence) is estimated to be 43.8 million.

The GLOBOCAN 2018 database is part of the IARC Global Cancer Observatory. It provides estimates of incidence and mortality for 36 types of cancer in 185 countries, as well as for all cancer sites combined.

An analysis of these results was published online September 12 in CA: A Cancer Journal for Clinicians.

"These new figures highlight that much remains to be done to address the alarming rise in the cancer burden globally and that prevention has a key role to play," commented IARC Director Christopher Wild, MD, in a statement. "Efficient prevention and early detection policies must be implemented urgently to complement treatments in order to control this devastating disease across the world."

Global Patterns

GLOBOCAN 2018 estimates that almost half of all cases and over one half of related deaths will occur in Asia, partly because almost 60% of the global population resides on that continent. Europe accounts for almost a quarter (23.4%) of the total number of global cases and about a fifth (20.3%) of cancer-related mortality, but it comprises only 9% of the world population. The Americas account for 13.3% of the global population, with 21% of cancer incidence and 14.4% of related mortality.

Conversely, cancer deaths in Asia (57.3%) and Africa (7.3%) are much higher than the incidence (48.4% and 5.8%, respectively) in those regions, largely because of the distribution of cancer types and higher case fatality rates.

The incidence rate for all cancers combined was about 20% higher in men (age‐standardized rate [ASR], 218.6 per 100,000 person-years) than in women (ASR, 182.6 per 100,000), although there was substantial variation across regions.

For men, there was an almost sixfold difference, from 571.2 per 100,000 in Australia/New Zealand to 95.6 per 100,000 in Western Africa. Similar ranges were seen for women, with a nearly fourfold difference, from 362 per 100,000 in Australia/New Zealand to 96.2 per 100,000 in South‐Central Asia.

These variations in incidence, note the authors, largely reflect differences in the type of exposures and cancer types, as well as the availability and use of screening and diagnostic imaging.

Associated mortality rates were also almost 50% higher for men than for women. Similar to incidence, there was wide variation across regions. Death rates ranged from 171 per 100,000 persons in Eastern Europe to 67.4 in Central America, and from 120.7 in Melanesia to 64.2 in Central America and Eastern Asia (excluding China).

Of note, the estimated cumulative risk of dying from cancer among women in 2018 is higher in East Africa (11.4%) than in North America (8.6%), Northern Europe (9.1%), and Australia/New Zealand (8.1%).

Major Cancer Types in 2018

Regarding incidence, cancers of the lung, female breast, and colorectum top the list and fall within the top five for mortality (first, fifth, and second, respectively). These three cancer types represent one third of cancer incidence and mortality globally.

For both men and women, lung cancer is the most commonly diagnosed cancer (11.6% of the total cases), and it is the leading cause of cancer death (1.8 million deaths, 18.4% of the total cancer deaths).

This is followed by female breast cancer (11.6%), prostate cancer (7.1%), and colorectal cancer (6.1%) in incidence, and by colorectal cancer (9.2%), stomach cancer (8.2%), and liver cancer (8.2%) for mortality.

Female breast cancer is the fifth leading cause of death (627,000 deaths, 6.6%), largely because the prognosis is often favorable, at least in high-income countries.

Cancers of the lung and female breast lead globally in terms of new cases; approximately 2.1 million diagnoses are estimated for 2018. These two cancers will account for about 11.6% of the total cancer incidence burden, the report notes.

Lung Cancer Trends in Women

Lung cancer is the leading cause of cancer death in women in 28 countries. The highest incidence rates were observed in North America, Northern and Western Europe (notably in Denmark and the Netherlands), China, and Australia, and New Zealand, with Hungary at the top of the list.

In contrast to men, in whom lung cancer rates have peaked and have declined in many countries, owing to reduced rates of smoking, the authors note that for women, the "epidemic is less advanced and, in contrast to men, most countries are still observing a rising trend in incidence."

In only a few populations, such as among white women in the United States, are there signs of a "peak and decline" among recent birth cohorts, although lung cancer incidence rates are now higher among young women than among young men. This pattern is seen largely among non‐Hispanic whites and Hispanics, and "intriguingly," it does not seem to be related to a sex‐specific difference in smoking behavior.

Smoking prevalence also does not seem to be the likely cause among Chinese women, in whom the incidence rate is 22.8 per 100,000, which is similar to that among women residing in several Western European countries (in France, it is 22.5 per 100,000). This is despite substantial differences between the two populations in smoking prevalence; the prevalence is quite low among Chinese women. The high rates of lung cancer are believed to reflect increased exposures to smoke from burning of charcoal for heating and cooking.

"Best practice measures embedded in the WHO Framework Convention on Tobacco Control have effectively reduced active smoking and prevented involuntary exposure to tobacco smoke in many countries," said Freddie Bray, PhD, head of the Section of Cancer Surveillance at the IARC, in a statement.

"However, given that the tobacco epidemic is at different stages in different regions and in men and women, the results highlight the need to continue to put in place targeted and effective tobacco control policies in every country of the world," he added.

CA Cancer J Clin. Published online September 12, 2018. Full text


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