More than 1.9 million people are diagnosed with colorectal cancer each year, making it the third most common cancer and the second leading cause of cancer death worldwide.

Yet the question of what an individual’s actual lifetime risk looks like — accounting for the fact that people may develop multiple cancers and face competing risks of dying from other causes — has remained unclear.

Now, the largest global assessment of lifetime colorectal cancer risk to date provides a comprehensive answer, revealing that the probability of developing the disease is about 2.7% globally, while the lifetime risk of dying from it is roughly 1.4%.

The findings expose profound disparities that track closely with geography, national development levels, sex, and age.

Colorectal cancer has long been recognised as a major global health threat, but its burden is far from evenly distributed.

Incidence and mortality rates vary dramatically across countries, and these differences are closely tied to socioeconomic development, dietary transitions, and the adoption of screening programmes.

In high-income nations, widespread colonoscopy use has helped detect and remove precancerous lesions, contributing to declining mortality among older adults.

Meanwhile, many low- and middle-income countries are witnessing rising incidence, driven by Westernised diets, sedentary lifestyles, and increasing rates of obesity and diabetes.

At the same time, early-onset colorectal cancer — in adults under 50 — has been on the rise in several regions, adding a new layer of complexity.

Based on these challenges, a comprehensive, population-based assessment of lifetime colorectal cancer risk — one that accounts for multiple primary cancers and competing mortality — is urgently needed to inform targeted prevention and control strategies worldwide.

Now, a team led by researchers from the Office for Cancer Registry at the National Cancer Centre, Chinese Academy of Medical Sciences and Peking Union Medical College, has conducted the first systematic global analysis of lifetime colorectal cancer risk across 185 countries.

Published in Cancer Biology & Medicine, the study draws on GLOBOCAN 2022 and United Nations population estimates, using a life-table method adjusted for multiple primary cancers to estimate the cumulative probability of developing and dying from the disease over a lifetime.

The numbers paint a striking picture. Globally, the lifetime risk of developing colorectal cancer is 2.69% — about one in 37 people — while the risk of dying from it is 1.39%.

Men face a slightly higher risk than women, and colon cancer consistently higher than rectal cancer in both incidence and mortality. But the real story lies in the disparities.

In very high Human Development Index countries, the lifetime risk of developing colorectal cancer soars to 5.17% — more than nine times the 0.57% risk seen in low-HDI nations.

Australia and New Zealand top the regional list with a 7.41% incidence risk, while Northern Europe records the highest mortality risk at 3.28%.

At the national level, Norway leads with a staggering 10.32% lifetime risk — meaning roughly one in ten Norwegians will develop colorectal cancer — followed closely by Denmark, New Zealand, and Japan.

At the opposite end, countries like Gambia, Chad, and Sierra Leone have risks below 0.6%.

The study also reveals that risk remains stable before age 40, peaks in middle age, and declines after 70 — but importantly, residual risk after 70 still stands at 1.55%.

Temporally, Thailand showed the steepest increase in lifetime risk between 2003 and 2017, while the United States and Austria saw significant declines, likely reflecting the impact of screening and lifestyle changes.

“The variation we observed is not just a matter of numbers — it tells a story about how health systems, dietary patterns, and public health investments shape cancer outcomes,” the authors said.

“In high-resource settings, we’re seeing that intensive screening and better treatment can actually bend the curve. But in many parts of the world, a diagnosis of colorectal cancer is still far too often a death sentence, not because the biology is different, but because access to early detection and quality care is lacking. These findings should serve as a wake-up call that global cancer control cannot be one-size-fits-all.”

The study’s implications are clear: prevention and screening strategies must be tailored to each population’s specific risk profile.

In high-HDI countries with higher lifetime risks, expanding evidence-based, age-stratified screening programmes and reinforcing lifestyle interventions — such as promoting fibre-rich diets and reducing red meat consumption — remain priorities.

In low-resource settings, where incidence is lower but mortality-to-incidence ratios are disproportionately high, the focus should shift to strengthening diagnostic capacity, improving treatment access, and building survivorship care infrastructure.

The findings also offer a benchmark for tracking progress over time and for allocating resources where they can have the greatest impact.

As colorectal cancer cases are projected to reach 3.56 million annually by 2050, the need for context-specific, data-driven strategies has never been more urgent.

Article: Global landscape and temporal trends in lifetime risk of colorectal cancer in 185 countries: a population-based study

Source: China Anti-Cancer Association