WhenI worked on the latest Global Burden of Disease cancer study, a global project that tracks cancer patterns and deaths across countries, I found myself pausing as the numbers loaded on the screen. Even as a scientist used to large datasets, the scale was hard to process.Behind every line of code was a family who might lose a parent or child to a cancer that could have been prevented or treated earlier. The projections for South Asia and sub-Saharan Africa were especially stark.

It was clear that millions of people would be living and dying with avoidable cancers in the decades ahead unless something changed.

Infectious outbreaksor antimicrobial resistance are often labelled as global health crises. Yet a quieter crisis has been gathering force for decades. Cancer is rising across every region of the world, and the steepest increases are now occurring in countries with the fewest resources.

As part of the Global Burden of Disease 2023 Cancer collaboration, a worldwide partnership of scientists who produce comprehensive estimates of disease and mortality, I co-authored a large study tracking cancer trends from 1990 to 2023 and projecting what the world could face by 2050.

For many years, cancer was widely viewed as a disease of affluence, concentrated in high income countries. Scientists now know that it affects all regionsand that an increasing proportion of the burden falls on low and middle income countries.

Many of these countries are now experiencing rapid lifestyle and environmental changes along with ageing populations, but without the parallel development of screening, diagnostic or treatment capacity. Our analysis highlights how quickly this transition is unfolding.

In 2023, our analysis estimated 18.5 million new cancer cases and 10.4 million deaths across 204 countries. Nearly one in six global deaths was caused by cancer. More than two-thirds of these deaths occurred in low- and middle-income countries, reflecting the scale of the challenge in regions where access to screening, pathology and treatment remains limited.

In our study, 41.7 per cent of cancer deaths in 2023 were attributable to modifiable risks. Tobacco, alcohol, unhealthy diets, high body mass index, air pollution and harmful workplace or environmental exposures all contributed.