So far, lung cancer has been the most diagnosed in previous reports, covering the past two decades, said Hyuna Sung, a leading cancer scientist and epidemiologist at the American Cancer Society, who authored the article.
“The change in classification signals the epidemiological transition of cancers,” Sung told CNN. “It was quite surprising news for us.”
There were 2.3 million new cases of breast cancer and 2.2 million new cases of lung cancer in 2020, according to the new report.
Sung said in an email to CNN on Thursday that there has been an increase in awareness of breast cancer, but mammograms may not explain the total increase in diagnoses of beast cancer over time.
“The upward trend in breast cancer probably reflects the increase in the prevalence of breast cancer risk factors, such as excess body weight, physical inactivity, alcohol consumption, postponing pregnancy, fewer births and less breastfeeding,” said Sung .
Researchers from the American Cancer Society in Atlanta and the International Agency for Cancer Research in France wrote in the report that lung cancer is still ranked as the leading cause of cancer death among men and women combined, with an estimated 1.8 million deaths, making up 18% of all cancer deaths.
Lung cancer was the leading cause of cancer deaths among men, accounting for 21.5% of cancer deaths in men. While breast cancer was the leading cause of cancer death among women, with 15.5%.
‘The burden of cancer … is growing rapidly around the world’
The report is based on cancer incidence and mortality data from the International Cancer Research Agency. Overall, the data suggests that there were about 19.3 million new cases and 10 million cancer deaths worldwide in 2020.
The five types of cancer most commonly diagnosed, according to the report, were: female breast cancer, lung cancer, colorectal cancer, prostate cancer and stomach cancer.
The data showed that the top five causes of cancer death were: lung, colorectal, liver, stomach and female breast cancer.
These estimates do not reflect the potential impact that Covid-19 could have on cancer diagnoses or deaths, since the estimates were taken from extrapolations of cancer data from previous years.
“No one knows the full extent of the pandemic’s impact on cancer statistics yet,” said Sung. “But there are many studies that suggest that we are already seeing delays in diagnosis and treatment.”
Looking ahead, the new report estimates that the global cancer burden is expected to reach 28.4 million cases in 2040 – an increase of 47% over last year.
Now, about 1 in 5 people worldwide will develop cancer in their lifetime, the WHO noted.
“The burden of cancer incidence and mortality is growing rapidly worldwide and reflects both aging and population growth, as well as changes in the prevalence and distribution of the main cancer risk factors, several of which are associated with development socioeconomic”. Freddie Bray, senior author of the report and head of the cancer surveillance section at the International Cancer Research Agency, said in a press release.
“Effective and resource-sensitive preventive and curative interventions are relevant to the diagnosis of cancer,” said Bray. “Tailor-made integration in health planning can serve to reduce the global burden of cancer and narrow the evident cancer inequalities between countries in transition and those in transition seen today.”