There were an estimated 20 million new cases of cancer in 2022, with more than 35 million new cases predicted by 2050.

According to forecasts by the World Health Organization’s cancer agency, the number of new cancer cases worldwide will reach 35 million in 2050, 77 percent more than in 2022.

A Opinion poll A study conducted by the WHO’s International Agency for Research on Cancer (IARC) cited tobacco, alcohol, obesity and air pollution as key factors in the predicted increase.

“Over 35 million new cases of cancer are predicted in 2050,” the IARC said in a statement, a 77 percent increase from the roughly 20 million cases diagnosed in 2022.

“The new estimates certainly highlight the scale of cancer today and indeed the growing cancer burden predicted over the next few years and decades,” Freddie Bray, head of cancer surveillance at IARC, told Al Jazeera on Thursday.

There were an estimated 9.7 million deaths from cancer in 2022, the IARC said in the statement along with its biannual report based on data from 185 countries and 36 cancer types.

About one in five people will develop cancer in their lifetime, with one in nine men and one in 12 women dying from the disease, it said.

“The rapidly growing global cancer burden reflects both population aging and growth and changes in people’s exposure to risk factors, some of which are related to socioeconomic development. Tobacco, alcohol and obesity are key factors in increasing cancer incidence, with air pollution still a major contributor to environmental risk factors,” the IARC said.

Lower income burden

The IARC also emphasized that the risk of cancer varies depending on where the patient lives.

The most developed countries are expected to see the largest increase in case numbers, with an additional 4.8 million new cases forecast in 2050 compared to estimates for 2022, the agency said.

But in percentage terms, countries at the bottom of the Human Development Index (HDI), used by the United Nations as an indicator of social and economic development, will see the largest proportional increase, up 142 percent.

Meanwhile, middle-tier countries are forecast to see a 99 percent increase, it said.

“One of the biggest challenges we see is that the proportional increase in the burden of cancer will be most noticeable in lower income, lower human development countries,” Bray told Al Jazeera.

“The burden is expected to double significantly by 2050.

“And these are essentially the countries that are currently ill-equipped to really tackle the cancer problem. And it’s getting bigger and there will be more patients in cancer hospitals in the future.”

Bray said that while there are more than 100 different types of cancer, the five most common cancers account for about 50 percent of cases.

“Lung cancer is the most common cancer worldwide … particularly in men, while breast cancer is certainly the most common cancer in women,” he said.

The IARC also said that various cancers are now increasingly affecting the population as lifestyles change. For example, colon cancer is now the third most common cancer and the second most common in terms of deaths. Colorectal cancer is particularly linked to age and lifestyle factors such as obesity, smoking and alcohol consumption.

“Much more investment should be made in early detection and detection [of cancers]. “Much more investment should be made in disease prevention” as well as palliative care for suffering people, Bray said.