As the world ages, cancer cases are projected to rise, hitting some countries like ‘a tidal wave’

CNN
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Around the world each year, tens of millions of people are told they have cancer, and millions die from the disease. Now, a report from the American Cancer Society projects that by 2050, the number of people with cancer could rise 77%.

The report, published Thursday in the journal CA: A Cancer Journal for Clinicians, found that in 2022 – the most recent year for which data was available – about 20 million cases of cancer were diagnosed alongside 9.7 million deaths from cancer.

Those estimates suggest that about 1 in 5 people who are alive now will develop cancer in their lifetime, and around 1 in 9 men and 1 in 12 women will die from the disease.

When it comes to the number of cases around the world, “we think that number will go up to 35 million by 2050, largely due to an increasing population in the aging population,” said Dr. William Dahut, chief scientific officer for the American Cancer Society.

The new report says population growth and aging are key drivers of the size of the world’s cancer burden, with the global population of about 8 billion people in 2022 projected to reach 9.7 billion by 2050.

But if more people also use tobacco and more have obesity, along with other risk factors for cancer, the projected number of cancer cases could get even higher, Dahut warned, especially in low-income countries.

“A lot of the drivers for cancer that we’ve traditionally seen in high-income countries, such as tobacco and obesity, these same cancer drivers are now moving into the low-income countries,” Dahut said, adding that this trend is worrisome.

“These are countries that do not have the tools to find cancer early, treat cancer appropriately and prevent it in ways that are often being done in other countries,” he said. “We’re worried that we’re going to see increased incidence rates, increased mortality rates, particularly in low-income countries, where the cancers are now being driven not only by traditional cancer drivers but also by external things such as tobacco and obesity.”

The new report includes global data on cancer incidence and death from the Global Cancer Observatory, a World Health Organization database.

The data shows that lung cancer was the most frequently diagnosed form worldwide in 2022, with almost 2.5 million new cases and more than 1.8 million deaths.

Overall, the top 10 cancer types in both men and women accounted for more than 60% of newly diagnosed cancer cases and cancer deaths, according to the report.

The most common cancer types are lung, breast in women, colorectal, prostate, stomach, liver, thyroid, cervical, bladder and non-Hodgkin lymphoma, according to the report. Lung cancer was also the leading cause of cancer deaths, followed by colorectal, liver, breast in women, stomach, pancreatic, esophagus, prostate, cervical and leukemia.

Cervical cancer was the leading cause of cancer death in 37 countries, mainly in sub-Saharan Africa, South America and southeastern Asia, according to the report. The HPV or human papillomavirus vaccine can reduce a person’s risk of cervical cancer, but globally, only about 15% of eligible girls have received the vaccine, according to the American Cancer Society. There are also disparities in screening for cervical cancer.

“With more than half of cancer deaths worldwide being potentially preventable, prevention offers the most cost-effective and sustainable strategy for cancer control,” Dr. Ahmedin Jemal, senior vice president of surveillance & health equity science at the American Cancer Society and senior author of the study, said in a news release. “Elimination of tobacco use alone could prevent 1 in 4 cancer deaths or approximately 2.6 million cancer deaths annually.”

Even though the causes of cancer can be complex, genetic or environmental, “about 50% of cancers are preventable,” Dr. Bilal Siddiqui, an oncologist and assistant professor at the University of Texas MD Anderson Cancer Center, who was not involved in the new report, said in an email.

“All patients should talk to their doctors to ensure they receive age-appropriate cancer screenings, and it’s important to make the key lifestyle changes that can reduce our risk for cancer, including stopping smoking, reducing alcohol intake, and staying physically active,” he said.

Tobacco remains “the principal cause of lung cancer,” according to the report, which adds that the disease can largely be prevented through effective tobacco control policies and regulations. As for other types of cancer, reducing excess body weight, reducing alcohol consumption, not smoking and increasing physical activity can help lower a person’s risk.

“While we do see lung cancers that are not related to smoking, the number one cause of lung cancer is smoking. And so obviously, there’s still much work to be done in the US and everywhere to continue to address the epidemic of smoking,” said Dr. Harold Burstein, an oncologist at Dana-Farber Cancer Institute and professor at Harvard Medical School, who was not involved in the new American Cancer Society report.

“Interestingly, pollution and other airborne environmental exposures probably increase the risk of lung cancer in many parts of the world. And so efforts to improve clean air or to reduce exposure to airborne pollution is another really important thing to think about,” Burstein said.

“Other things that people can do to reduce their cancer mortality include screening for early cancer detection and better outcomes. In the US, we have very vigorous opportunities for screening with mammography, colonoscopy and Pap smears, but these are still often under-utilized by many parts of our society,” he said. “In the more advanced economies, like the US, we have seen remarkable declines in the rates of mortality from breast cancer and colon cancer, probably about half of that due to early detection.”

The new report details how many low-income countries have high cancer death rates despite low cancer incidence, largely due to a lack of access to screening tools to spot the disease early and advanced treatment services.

The report helps highlight not only these global trends in cancer but also how cancer is becoming a “bigger health problem” in lower- and middle-income regions of the world, Burstein said.

“Cancer is a tidal wave coming into their communities,” he said.

“They do not have screening mammograms in most of sub-Saharan Africa. They do not have screening mammograms in China. They do not have routine colonoscopies in many parts of the world,” he said. “The report says that the prevalence of cancer will double in low- and middle-income countries in the next 25 years. And so, dealing with both the surging prevalence, the need for early detection and screening, and then the complex treatment and care of patients with cancer is going to be a huge challenge for health care systems that are already stretched.”