The collaborative report Global Cancer Statistics 2020 from the American Cancer Society and the International Agency for Research on Cancer shows that female breast cancer is now the most commonly diagnosed cancer, overtaking lung cancer for the first time.

Data show that 1 in 5 men and women worldwide develop cancer during their lifetime, and 1 in 8 men and 1 in 11 women die from the disease, according to the study.

The report describes cancer incidence and mortality at the global level and according to sex, geography, and levels of social and economic development. The analysis further discusses associated risk factors and prospects for prevention for each of 10 major cancer types, representing more than 60% of the newly diagnosed cancer cases and more than 70% of deaths from cancer.

An estimated 19.3 million new cancer cases and almost 10 million cancer deaths occurred in 2020, according to the report. Further, female breast cancer was the most commonly diagnosed cancer, with an estimated 2.3 million new cases (11.7%), followed by lung (11.4%), colorectal (10.0%), prostate (7.3%), and stomach (5.6%) cancers.

“Dramatic changes in lifestyle and built environment have had an impact on the prevalence of breast cancer risk factors such as excess body weight, physical inactivity, alcohol consumption, postponement of childbearing, fewer childbirths, and less breastfeeding,” the study authors wrote in a press release. “The increasing prevalence of these factors associated with social and economic transition results in a convergence toward the risk factor profile of transitioned countries and is narrowing international gaps in the breast cancer morbidity.”

The death rates of breast cancer among women in transitioning countries were even higher compared with the rates among women in transitioned countries, despite the substantially lower incidence rates.

“As the poor outcome in these countries is largely attributable to a late-stage presentation, efforts to promote early detection, followed by timely and appropriate treatment, are urgently needed through the implementation of evidence-based and resource-stratified guidelines,” said lead study author Hyuna Sung, PhD, in a press release.

The data show that lung cancer remained the leading cause of cancer death, with an estimated 1.8 million deaths (18%), followed by colorectal (9.4%), liver (8.3%), stomach (7.7%), and female breast (6.9%) cancers.

Lung cancer death rates are 3 to 4 times higher in transitioned countries than in transitioning countries. However, this pattern may well change as the tobacco epidemic evolves, given that 80% of smokers reside in low- and middle-income countries. The disease can be largely prevented through effective tobacco control policies and regulations, according to the study authors.

The report shows an estimated 28.4 million new cancer cases are projected to occur in 2040, a 47% rise from 2020 globally. Additionally, transitioning countries are experiencing a larger relative increase in cancer incidence (64% to 95%) versus transitioned (32% to 56%) countries due to demographic changes. The study authors noted that this may be further affected by increasing risk factors associated with globalization and a growing economy.

Data in this report do not reflect the ramifications of the COVID-19 pandemic, as they are based on cancer data collected in earlier years, and the full extent of the impact in different world regions is currently unknown. The report lists delays in diagnosis and treatment, including suspension of screening programs and reduced availability of and access to care. These are anticipated to cause a short-term decline in cancer incidence followed by increases in advanced-stage diagnoses and cancer mortality in some settings, according to the study.

“The burden of cancer incidence and mortality is rapidly growing worldwide, and reflects both aging and growth of the population, as well as changes in the prevalence and distribution of the main risk factors for cancer, several of which are associated with socioeconomic development,” said senior study author Freddie Bray, BSc (Hons), MSc, PhD, in a press release. “Effective and resource-sensitive preventative and curative interventions are pertinent for cancer diagnosis. Tailored integration into health planning can serve to reduce the global burden of cancer and narrow the evident cancer inequities between transitioning and transitioned countries observed today.”

REFERENCE
Female breast cancer surpasses lung as the most commonly diagnosed cancer worldwide. American Cancer Society. http://pressroom.cancer.org/GlobalCancerStats2020#:~:text=Cancer%20ranks%20as%20a%20leading,and%20the%20International%20Agency%20for. Published February 4, 2021. Accessed February 5, 2021.