Breast cancer now tops the list of the most commonly diagnosed cancers worldwide, surpassing lung cancer for the first time, according to the latest global cancer burden estimates from the International Agency for Research on Cancer (IARC).
Breast cancer among women accounted for 11.7% of the estimated 19.3 million new cancer cases in 2020 ― and about 25% of all cancer cases among women. Lung cancer accounted for 11.4% of new cases, reports the IARC, part of the World Health Organization.
However, lung cancer remains the leading overall cause of cancer mortality, accounting for 18.0% of 10 million cancer deaths. Breast cancer ranks fifth as a cause of cancer mortality, accounting for 1 of every 6 cancer deaths in women and 685,000 deaths overall (6.9%) in 2020, but it ranks first in incidence in 159 countries and first in mortality in 110 countries, the data show.
The increase in breast cancer cases is likely attributable to the effects of “marked changes in lifestyle, sociocultural contexts, and built environments” in many countries, says the IACR. These include delayed childbearing, having fewer children, increased rates of overweight and obesity, and decreasing levels of physical activity, the IACR explains in a press release.
These new data underscore the importance of focusing on cancer prevention, IARC Director Elisabete Weiderpass, MD, states in the press release.
“Effective interventions for prevention and early detection are available and must be integrated into cancer planning to control the predicted upsurge of this devastating disease,” she said.
Weiderpass also notes that the “overwhelming need for evidence-based and resource-stratified guidelines that support the phased implementation of breast cancer early detection and treatment into real-world practice.”
To that end, the WHO and the IARC will launch a global breast cancer initiative in 2021 to improve population-level outcomes through a focus on more timely diagnosis and comprehensive treatment, she adds.
The most common cancer diagnoses worldwide after breast cancer and lung cancer are colorectal cancer (10.0%), prostate cancer (7.3%), and stomach cancer (5.6%).
The leading causes of cancer deaths after lung cancer are colorectal cancer (9.4%), liver cancer (8.3%), stomach cancer (7.7%), and breast cancer among women.
One in five people will develop cancer
The IACR estimates that 1 in 5 people will develop cancer in their lifetime and that 1 in 8 men and 1 in 11 women will die from it.
Among women, breast cancer is the most common cancer type and the most common cause of cancer death. Colorectal cancer and lung cancer are the second and third most common cancer types and the third and second most common causes of cancer death, respectively.
Among men, lung cancer is the most common cancer type and the most common cause of cancer death. Prostate cancer and colorectal cancer are the second and third most common cancer types, and liver cancer and colorectal cancer are the second and third most common causes of cancer death.
“Worldwide, an estimated 28.4 million new cancer cases are projected to occur in 2040, a 47% increase from the estimated 19.3 million cases in 2020,” the IARC notes.
The agency derives its estimates from the GLOBOCAN 2020 database, which tracks 185 countries and 36 types of cancer and is accessible through the IARC Global Cancer Observatory.
A version of this article first appeared on Medscape.com.