Incidence of non-melanoma skin cancer, the most common cancer worldwide with 7.7 million cases resulting in 65,000 deaths, accounted for the largest change in the Global Burden of Disease (GBD) 2017 study, recently published in JAMA Oncology.
The aim of the GBD study is to describe cancer incidence, mortality, years of life lost, years lived with disability, and disability-adjusted life-years (DALY) for 195 countries from 1990 to 2017.
“The national epidemiological profiles of cancer burden in the GBD study show large heterogeneities, which are a reflection of different exposures to risk factors, economic settings, lifestyles, and access to care,” wrote the Global Burden of Cancer Collaboration, which authored the piece. “The GBD study can be used by policy makers and other stakeholders to develop and improve local cancer control in order to achieve the global targets and improve equity in cancer care.”
The study looked at the burden of 29 different cancer types across 195 countries between 1990 and 2017, evaluating cancer incidence, mortality, years lived with a disability, years of life lost, and disability-adjusted life years. The results were then sorted by socio-demographic index (SDI) which accounts income, education level, and total fertility rate.
Results showed 24.5 million cancer cases worldwide in 2017 and 9.6 million cancer deaths. Ninety-seven percent of DALYS related to cancer were from years of life lost, while the remaining came from years lived with disability. The most common cancers, after non-melanoma skin cancer, were lung cancer (including tracheal and bronchus cancers), breast cancer, colorectal cancers, prostate cancer, stomach cancer, liver cancer, cervical cancer, non-Hodgkin lymphoma, and bladder cancer.
Incidence of non-melanoma skin cancer grew the most with a 20% increase from the 2016 GBD study. This increase was attributed to population growth and aging. However, there may be an explanation for this increase. “Despite being the most common incident cancer in many populations, cancer registry data to inform incidence estimates are often unreliable or nonexistent, the study authors explained. “For GBD 2017 we have therefore used Marketscan data for the United States, which has led to substantially higher estimates for (non-melanoma skin cancer).
Women were more likely to present with cases of colorectal cancer (n = 819,000) and breast cancer (n = 1.9 million), with breast cancer being the leading cause of cancer deaths (n = 601,000) and DALYs (n = 17.4 million). For men, lung and prostate cancers were the most common (n = 1.5 million cases and 1.3 million, respectively) with the most deaths and DALYs being from lung cancers (n = 1.3 million deaths and 28.4 million, respectively).
The odds of developing cancer were the lowest in the low SDI quintile (1 in 7) and the highest in the high SDI quintile (1 in 2) for both sexes.
“Our analysis shows how cancer has increased in importance as a global health problem. Although it ranked sixth in 1990 among the top causes for DALYs worldwide, it has risen to the second place in 2017 behind cardiovascular diseases,” the study authors wrote, adding that cancer now occupies the second place in the ranking of global deaths, years of life lost, and DALYs, and is among the top 2 leading causes of deaths, years of life lost, and DALYs in the highest 3 SDI quintiles.
“This shift in disease burden owing to the demographic and epidemiological transitions has important implications on health policy: ensuring access to universal health coverage and protection against catastrophic health expenditure directly related to the cancer treatment, but also against the long-term costs associated with a cancer diagnosis for a household, has to be prioritized,” they wrote.