The global number of cancer cases and deaths between 1990 and 2023 showed a sharp increase, despite advances in cancer treatment and efforts to tackle cancer risk factors over that same period.
And experts warn that lower-income countries are expected to be hardest hit by an escalation in new cases over the next quarter century, with an anticipated increase of nearly 75% in death statistics.
A new analysis from the Global Burden of Disease Study Cancer Collaborators, published in The Lancet, forecasts that without urgent action and targeted funding, 30.5m people will receive a new cancer diagnosis and 18.6m are expected to die from cancer in 2050 – with more than half of new cases and two-thirds of deaths occurring in low- and middle-income countries (LMICs).
The predicted rise is despite advances in treatments and efforts to curb risk factors, with the increases likely to be driven mainly by population growth and ageing populations, said the study. Currently, more than 40% of cancer deaths are linked to 44 “modifiable” risk factors, such as smoking, unhealthy diet and high blood sugar.
These played a role in 46% of cancer deaths among men in 2023, attributed mainly to tobacco, diet, alcohol, occupational risks and air pollution.
Among women, for whom 36% of cancer deaths were linked to modifiable risks, the key triggers were tobacco, unsafe sex, diet, obesity and high blood sugar.
“There are tremendous opportunities for countries to target these risk factors, potentially preventing cases of cancer and saving lives,” said Dr Theo Vos, one of the study’s authors and a researcher at the US-based Institute for Health Metrics and Evaluation (IHME).
Global burden
Using data from population-based cancer registries, vital registration systems, and interviews with family or caregivers of people who have died from cancer, the analysis provides updated and extended global, regional, and national estimates from 1990 to 2023 in 204 countries and territories for 47 cancer types or groupings and 44 attributable risk factors.
The analysis forecasts the cancer burden up to 2050 and examines cancer-specific progress thus far towards the UN Sustainable Development Goal (SDG) to reduce non-communicable disease deaths, including from cancer, by a third between 2015 and 2030.
In 2023, there were 18.5m new cancer cases and 10.4m deaths worldwide, both major increases since 1990. Death rates, however, have fallen due largely to declines in wealthier countries.
The analysis predicts that lower-income countries will account for more than half of new cancer cases and two-thirds of deaths between now and 2050, and Meghnath Dhimal, from the Nepal Health Research Council who also worked on the study, called this “an impending disaster”.
The researchers urged improved access to faster, more accurate cancer diagnoses, quality treatment, and supportive care, particularly in lower-income countries.
“There are cost-effective interventions for cancer in countries at all stages of development,” Dhimal said.
Far off target
While the overall number of cancer cases and deaths is expected to rise substantially from 2024 to 2050, encouragingly, when the global case and mortality rates are adjusted to account for differences in age, they are not forecast to increase.
This suggests that most of the increases in cases and deaths will be due to population growth and the rise of ageing populations.
Such improvement, however, is still far away from the ambitious SDG to reduce premature mortality by a third by 2030.
“Cancer remains an important contributor to disease burden globally and our study highlights how it is anticipated to grow substantially over the coming decades, with disproportionate growth in countries with limited resources,” said lead author Dr Lisa Force from the IHME, University of Washington.
“Despite the clear need for action, cancer control policies and implementation remain under-prioritised in global health, and there is insufficient funding to address this challenge in many settings.”
She said ensuring equitable cancer outcomes globally needed greater efforts “to reduce disparities in health service delivery like access to accurate and timely diagnosis, and quality treatment and supportive care”.
Striking differences
Cancer deaths rose to 10.4m and new cases jumped to 18.5m globally in 2023 (both excluding non-melanoma skin cancers) – increases of 74% and 105%, respectively, since 1990.
However, although the age-standardised death rates decreased by 24% worldwide between 1990 and 2023, the reduction in rates appears to be driven by high- and upper-middle-income countries. Age-standardised rates of new cases worsened in low-income (up by 24%) and lower-middle-income countries (up by 29%), underscoring the disproportionate growth occurring in settings with lower resources.
Between 1990 and 2023, Lebanon had the greatest percentage increase in age-standardised incidence and mortality rates for both sexes combined, while United Arab Emirates had the greatest decrease in age-standardised incidence, and Kazakhstan had the greatest decrease in age-standardised death rates.
In 2023, breast cancer was the most diagnosed cancer worldwide for both sexes combined, with tracheal, bronchus, and lung (TBL) cancer being the leading cause of cancer deaths.
Top priority
While the study uses the best available data, the authors note that the estimates are constrained by a lack of high-quality cancer data, particularly in resource-limited countries.
They also point out that current GBD estimates do not account for several infectious diseases known to be causally linked to cancers which are common in some lower-income countries, such as Helicobacter pylori and Schistosoma haematobium, which probably under-estimates the cancer burden linked to modifiable risks.
Neither do they incorporate the impact of the Covid-19 pandemic or recent conflicts on the cancer burden. Finally, estimates of future cancer burden do not account for the impact of potential new breakthrough discoveries that could alter the longer-term trajectory of cancer burden.
Writing in a linked comment, Dr Qingwei Luo and Dr David Smith from the University of Sydney, who were not involved in the study, said: “To ensure meaningful progress in reducing the global cancer burden, it is imperative that governments prioritise funding, strengthen health systems, reduce inequalities, and invest in robust cancer control initiatives and research on prevention, intervention, and implementation – because the future of cancer control depends on decisive, collective action today.”
See more from MedicalBrief archives:
Analysis projects global cancer deaths will double by 2050
Breast cancer deaths to rise 68% by 2050 – WHO study
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