A report released on World Cancer Day (4th February 2015) has found that lung cancer is now the leading cause of cancer death in females in developed countries. The analysis was led by researchers at the American Cancer Society (GA, USA) and was carried out in collaboration with the International Agency for Research on Cancer (IARC; Lyon, France). The findings, which were reported in CA: A Cancer Journal for Clinicians, draw on worldwide cancer incidence and mortality estimates for 2012, reported by IARC in their GLOBOCAN series.
The researchers demonstrated that lung cancer now results in more deaths than breast cancer in women in developed countries and suggest that this change may be as a result of the later occurrence of the tobacco epidemic in women. The same pattern was not exhibited in women in developing countries, where breast cancer remains as the leading cause of cancer deaths.
For several decades lung cancer has been the leading cause of cancer death in men in both developed and developing countries; the study carried out by the American Cancer Society and the IARC highlights that this is a pattern beginning to be displayed in women as well.
Based on GLOBOCAN estimates, approximately 14.1 million new cancer cases and 8.2 million cancer deaths occurred worldwide in 2012. This increase has been attributed to both a growing and aging population, as well as an increase in risk factors associated with economic growth and urbanization, e.g., smoking, being overweight, sedentary lifestyles and altering reproductive patterns.
Over the years, the burden of cancer has shifted to less developed countries, which now account for approximately 57% of cases and 65% of cancer deaths worldwide. Lung and breast cancer are the most commonly diagnosed cancers and the leading causes of cancer death in men and women, respectively, in less developed countries.
Prostate and breast cancer are the most commonly diagnosed cancers among men and women, respectively, in more developed countries; however, lung cancer is the leading cause of death in both men and women. Colorectal cancer has also become a common cause of cancer death in both developed and developing countries. In less developed countries, liver and stomach cancer among men and cervical cancer among women are also leading causes of cancer death.
Although incidence rates for all cancers combined are nearly twice as high in more developed countries than in less developed countries in both genders, mortality rates are only 8–15% higher in more developed countries due to regional differences in the mix of cancers, which is itself influenced by risk factors, detection practices, and the availability of treatment.
“A substantial proportion of the worldwide burden of cancer can be prevented through the application of existing cancer control knowledge, including tobacco control, vaccination (for liver and cervical cancers), early detection and the promotion of physical activity and healthy dietary patterns,” the researchers explained. The study also indicates that the application of appropriate treatments and palliative care can further alleviate suffering and that the identification of the causes of several major cancers, including prostate and blood cancers, is needed.
The research also reported that in developing countries, a number of cancers that were once rare are now becoming more common as a more western lifestyle is adopted. The research team concluded that “a coordinated and intensified response from all sectors of society, including governments, civil society, the private sector and individuals, is required to seize control of the growing burden of cancer.”
Written by Hollie Franklin
Sources: Torre LA, Bray F, Siegel RL, Ferlay J, Lortet-Tieulent J, Jemal A. Global cancer statistics, 2012. CA: Cancer J. Clin. doi: 10.3322/caac.21262 (2015) (Epub ahead of print); American Cancer Society press release