A new Lancet study warns of stark inequities, as poorer nations face the sharpest rise despite prevention opportunities.
The global cancer burden is forecast to rise dramatically over the next 25 years, with annual deaths expected to reach 18.6 million by 2050 – a 75% increase from 2024 – according to new research published in The Lancet.
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, the researchers also reported.
However, there is some good news in the report, with Australia seeing a reduction in the age-standardised mortality rate (ASMR) of cancer. In 1990 the ASMR was 162.0 per 100,000 people – in 2023 that had fallen by 33.3% to 108.3 per 100,000.
Results for the ASMR in other countries include the US (a decline of 32.5% in the same period), the UK (down 23.4%), Germany (down 24.9%) and France (down 25.9%).
The biggest drop was seen in Kazakhstan, where the ASMR fell 58.2% from 195.2 per 100,000 people in 1990 to 81.6 people per 100,000 people in 2023.
The worst result was seen in Lebanon, where the ASMR ballooned by 80.0%, from 65.2 per 100,000 people in 1990 to 117.3 people per 100,000 people in 2023.
The analysis, part of the Global Burden of Disease (GBD) Study Cancer Collaborators, assessed cancer trends across 204 countries and territories between 1990 and 2023, and projected cases and deaths to 2050. It covered 47 cancer types and 44 attributable risk factors.
The study found that the number of new cancer cases more than doubled since 1990 to 18.5 million in 2023, while deaths increased by 74% to 10.4 million.
By 2050, new cases are expected to rise a further 61% to 30.5 million, with more than half of diagnoses and two-thirds of deaths occurring in low- and middle-income countries (LMICs).
Although age-standardised death rates have declined globally by 24% since 1990, largely due to advances in high-income countries, LMICs have seen worsening incidence and mortality rates, underscoring inequities in access to prevention and care.
The study estimates that 42% of cancer deaths (4.3 million in 2023) were attributable to modifiable risk factors, including tobacco use, unhealthy diets, high blood sugar, alcohol, obesity and unsafe sex.
Tobacco remains the leading cause worldwide, accounting for 21% of cancer deaths, though unsafe sex was the top driver in low-income countries, linked to 12.5% of deaths.
“With four in 10 cancer deaths linked to established risk factors, including tobacco, poor diet and high blood sugar, there are tremendous opportunities for countries to target these risk factors, potentially preventing cases of cancer and saving lives, alongside improving accurate and early diagnosis and treatment to support individuals who develop cancer,” said co-author Dr Theo Vos from the University of Washington’s Institute for Health Metrics and Evaluation (IHME).
“Reducing the burden of cancer across countries and worldwide demands both individual action and effective population-level approaches to reduce exposure to known risks.”
The findings put a massive dampener on the ambitious UN Sustainable Development Goal (SDG) to reduce premature mortality due to non-communicable diseases, which include cancer, 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, also from the IHME.
“Despite the clear need for action, cancer control policies and implementation remain underprioritised in global health, and there is insufficient funding to address this challenge in many settings.
“Ensuring equitable cancer outcomes globally will require greater efforts to reduce disparities in health service delivery such as access to accurate and timely diagnosis, and quality treatment and supportive care.”
The results also highlight stark disparities in the cancer burden between countries based on socio-economic status.
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.
The authors called for cancer prevention to be a component of policies in low to middle-income countries.
Co-author Dr Meghnath Dhimal from the Nepal Health Research Council said the findings underscored the need for equitable cancer-control efforts to ensure all people with cancer receive the care they need where and when they need it.
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“The rise of cancer in LMICs is an impending disaster,” said Dr Dhimal.
“There are cost-effective interventions for cancer in countries at all stages of development. These cancer burden estimates can help broaden the discussion around the importance of cancer and other non-communicable diseases in the global health agenda.
“To control the growth of non-communicable diseases including cancer in LMICs, an interdisciplinary approach for evidence generation and multi-sectoral collaboration and coordination for implementation are urgently needed.”
According to Dr Force, “These new estimates and forecasts can support governments and the global health community in developing data informed policies and actions to improve cancer control and outcomes around the world. They can also support tracking of progress towards global and regional cancer targets.”
While the study used the best available data, the authors noted that the estimates were 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 likely underestimates the cancer burden linked to modifiable risks.
The also did not incorporate the impact of the covid pandemic or recent conflicts on the cancer burden. Estimates of future cancer burden also did 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 in The Lancet, Dr Qingwei Luo and Dr David P. Smith from The University of Sydney and Cancer Council NSW, who were not involved in the study, said research and funding were paramount.
“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,” they wrote.
