Global cancer incidence in older adults, 2012 and 2035: A population-based study.

Population ageing has substantially contributed to the rising number of new cancer cases worldwide. We document cancer incidence patterns in 2012 among older adults globally, and examine the changing magnitude of cancer in this age group over the next decades. Using GLOBOCAN 2012 data, we presented the number and proportion of new cancer cases, and the truncated age-standardised incidence rates among adults aged 65 years and older for all cancer sites combined and for the five most common cancer sites by world region. We calculated the incidence in 2035 by applying population projections, assuming no changes in rates. In 2012, 6.7 million new cancer cases (47.5% of all cancers) were diagnosed among older adults worldwide, with marked regional disparities. Nearly 48% of these cases occurred in less developed regions. Lung, colorectal, prostate, stomach and breast cancers represented 55% of the global incidence, yet distinct regional patterns were observed. We predict 14 million new cancer cases by 2035, representing almost 60% of the global cancer incidence. The largest relative increase in incidence is predicted in the Middle East and Northern Africa (+157%), and in China (+155%). Less developed regions will see an increase of new cases by 144%, compared to 54% in more developed regions. The expected increase in cancer incidence at older ages will have substantial economic and social impacts globally, posing considerable and unique challenge to healthcare systems in every world region, especially in those with limited resources and weaker health systems.