Scientists expect cancer rates to nearly double across the globe in the next quarter-century, fueled by aging, obesity, and tobacco and alcohol use.
An estimated 20 million cases of cancer were diagnosed worldwide in 2022, up from 18 million in 2020. That number will rise by 77% to 35 million by 2050, the World Health Organization’s International Agency for Research on Cancer (IARC) predicted Thursday.
Highly developed countries will experience the greatest absolute increase in cancer cases over the next 25 years. Countries with lower levels of development, however, will see a disproportionate increase in cancer rates, potentially putting a greater burden on their health systems. The IARC projects a 142% increase in cancer rates for countries with a low-level of development, compared to a 99% increase for countries with a medium-level of development, between now and 2050.
“The impact of this increase will not be felt evenly across countries of different [development] levels,” Dr. Freddie Bray, head of the Cancer Surveillance Branch at IARC, said in a news release about the data. “Those who have the fewest resources to manage their cancer burdens will bear the brunt of the global cancer burden.”
While progress has been made in early cancer detection and treatment, “significant disparities in cancer treatment outcomes exist not only between high- and low-income regions of the world, but also within countries,” Dr. Cary Adams, head of international NGO Union for International Cancer Control, added.
“Where someone lives should not determine whether they live,” she said. “This is not just a resource issue, but a matter of political will.”
Lung, female breast cancers remain top global concerns
Lung cancer and female breast cancer have been in a neck-and-neck race for global supremacy, with the latter surpassing the former for the first time in 2020.
That trend reversed itself two years later. Persistent tobacco use in Asia helped push global lung cancer diagnosis rates ahead of female breast cancer in 2022, the IARC said Thursday.
The cancers most commonly diagnosed in the world two years ago, according to the organization, were:
- Lung cancer: 2.5 million new cases
- Breast cancer: 2.3 million
- Colorectal cancer: 1.9 million
- Prostate cancer: 1.5 million
- Stomach cancer: 970,000
While lung cancer diagnoses slightly surpassed those of breast cancer in 2022, breast cancer remained the most common cause of cancer when both genders were considered in the vast majority of countries: 157 out of 185.
Two years before, in 2020—the last prior year for which data is available—breast cancer ranked first in diagnosis rate, followed by lung and colorectal cancers.
- Breast cancer: 2.3 million new cases
- Lung cancer: 2.2 million
- Colorectal cancer: 1.9 million
- Prostate cancer: 1.4 million
- Stomach cancer: 1.1 million
In 2022, breast cancer remained the most commonly diagnosed cancer in women globally, and the leading cause of cancer death, according to the IARC. Lung and colorectal cancers were the second and third most common types of cancer diagnosed in women and causes of cancer deaths, respectively.
For men, lung cancer was the most commonly diagnosed cancer and the leading cause of cancer death globally in 2022, followed by liver and colorectal cancers.
Aside from being the most commonly diagnosed cancer in 2022, lung cancer was the deadliest cancer as well, causing 1.8 million deaths, followed by colorectal and liver cancers.
- Lung cancer: 1.8 million deaths
- Colorectal cancer: 900,000
- Liver cancer: 760,000
- Breast cancer: 670,000
- Stomach cancer: 660,000
Lung cancer was also the deadliest cancer in 2020, with a descending list nearly identical to 2022’s.
- Lung: 1.8 million deaths
- Colorectal: 935,000
- Liver: 830,000
- Stomach: 769,000
- Breast: 685,000
2024 cancer deaths expected to hit record high in U.S.
The new global statistics come just days after the American Cancer Society (ACS) released its 2024 cancer forecast earlier this month. The organization anticipates new cancer diagnoses to surpass 2 million for the first time this year, with four cancers for which early screenings exist—breast, prostate, colorectal, and cervical—on the rise.
While the risk of dying from cancer in the U.S. has steadily declined over the years—thanks to advances in cancer detection and treatment and a reduction in smoking rates—diagnosis rates of certain types of cancers are increasing, particularly among population subsets.
The increases, according to the new report, include:
- Colorectal cancer in people younger than 55 years of age
- Liver cancer in women
- Cervical cancer in women ages 30 through 44
Six types of cancer with rising diagnosis rates are associated with excess body weight, the organization notes, including:
- Endometrial
- Liver
- Kidney
- Pancreas
- Colorectal
- Breast
Perhaps most concerning: The age of the average cancer patient is decreasing. In 1995, 61% of cancer diagnoses were among those ages 65 and older. But by 2020, that proportion had dropped to 58%.
Meanwhile, cancer rates among middle-age and younger adults are rising. Collectively, those under 50 were the only age group to see an increase in cancer diagnoses from 1995 through 2020.
Colorectal cancer diagnoses, in particular, are trending upward among younger adults—those below the age of 50—according to the ACS. In the late 1990s, colorectal cancer was the fourth leading cause of cancer death among men and women in this age group. Now, it’s the leading cause of cancer death for men in this age group, and the No. 2 cause for women. Scientists from the ACS speculate that lifestyle factors particularly common among those born in 1950 and later—like obesity, high consumption of processed meat and alcohol, low levels of physical activity and fiber consumption, and smoking—are fueling this change.
Italian researchers, in a study published this month in the Annals of Oncology, draw a similar conclusion. Obesity and alcohol consumption are contributing to colorectal cancer’s rising death toll among young adults, they assert. This year, bowel cancer deaths among young people—Millennials and Gen Xers aged 25-49—are predicted to rise in some European countries for the first time, according to their report.
