Global Rise of Colorectal Cancer (CRC)
Introduction
Colorectal cancer (CRC) remains a major global public health challenge, with evolving patterns of incidence, mortality, and demographic distribution.
Although overall death rates have declined in many high-income regions due to advances in screening and treatment, the global incidence of colorectal cancer continues to rise, with particularly concerning increases among younger adults.
Variations in risk by age, sex, socioeconomic deprivation, and ethnicity highlight the complex interplay between lifestyle factors, healthcare access, and biological predisposition.
Understanding these trends is essential for informing prevention strategies, optimising screening programmes, and addressing persistent health inequalities in colorectal cancer outcomes.
1. Global Rise of Colorectal Cancer
Several studies have analysed decades worth of epidemiological data relating to the global incidence of colorectal cancer (CRC) and outcomes including disability and death.
One of these studies was published in 2019, a systematic analysis of data spanning across 195 countries covering the period from 1990 to 2017. <tt>1000</tt>
The findings showed age-standardised incidence rate increased by 9.5% globally since 1990, while age-standardised mortality rate decreased by 13.5% since 1990, despite the rise in incidence.
This could suggest the drivers of colorectal cancer incidence are still persistent, despite co-existing with improved social awareness, lifestyle modification and screening rates, which have helped both identify and treat the disease more efficiently.
Interestingly, several countries considered to be highly developed, indicated by a Socio-demographic Index (SDI)/Healthcare Access and Quality (HAQ) Index, had among the highest incidences of colorectal cancer compared to countries of low and moderate SDI/HQA.
It is possible the advancements in healthcare among high SDI/HQA countries might not ameliorate enough the exposure to risk factors (e.g., westernised diets, smoking, alcohol), which are suspected to continue to drive the incidence of colorectal cancer globally.
The two regions in the world that experienced a decrease in age-standardised incidence rate were high-income North America (North America and Canada) and Australasia (Australia and New Zealand).
These two regions were also among the first to adopt nationwide screening programmes. Such programmes are particularly useful for detecting colorectal cancer, as a colonic polyp can slowly transform into cancer in as little as 5 years or as long as 20 years.<tt>2210</tt>
Colonoscopy-based screening programmes have been shown to be both effective in reducing the incidence and mortality of colorectal cancer (CRC).
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2. Age-Related Trends
Historically, the majority of colorectal cancer (CRC) cases have always occurred, and still do, in adults over 55 years old. However, there are several concerning trends which seem to be developing.<tt>1001</tt><tt>1002</tt>
In 2022, ~88.57% of colorectal cancer (CRC) cases in England (UK) occurred in adults over 55 years old. By comparison, two decades earlier, in 2002, this age group accounted for 91.1% of colorectal cancer (CRC) cases, representing a decrease of 2.53 percentage points in the proportion of cases occurring in older adults.
In contrast, 11.42% (or 1677) of colorectal cancer (CRC) incidence in 2022 occurred in those <u>under</u> 55 years old, compared to 8.9% (or 666) of colorectal cancer (CRC) incidence in 2002.
These statistics show young people are accounting for a greater proportion of the increasingly higher annual incidence of colorectal cancer (CRC) in England. Similar findings are shared across many developed and developing countries.<tt>1015</tt>
With an increase in population, there will inevitably be an increase in the incidence of many diseases. The population in England has risen 15.05% between 2002 and 2022.<tt>1014</tt>
However, this is when we consider the 'rate' to account for differences in population size over time. Incidence rates are commonly expressed as the number of new cases per 100,000 people. This metric allows direct comparison of a population after accounting for changes in the size of the population.
In 2002, the rate of colorectal cancer (CRC) per 100,000 for males aged 25-29 in England was 0.8 per 100,000. The incidence rate for the same group has only increased since to 1.9 per 100,000 in 2022. <tt>1001</tt>
Although the reason for these epidemiological shifts is not known for certain, the body of evidence points towards lifestyle habits being at least in part responsible. <tt>2211</tt>
3. Gender Related Trends
Colorectal cancer (CRC) demonstrates a higher incidence in males compared to females in England, which is consistent with global findings.<tt>1000</tt><tt>1001</tt><tt>1002</tt>
In 2022, among the 39,933 individuals diagnosed with colorectal cancer in England, 55.2% were male and 44.8% were female. This ratio has remained relatively consistent over the last two decades.<tt>1002</tt>
For context, about 10% of colorectal cancer is due to hereditary syndromes (e.g., Lynch syndrome and FAP) caused by germline mutations independent of sex.
Approximately 25% show a familial pattern characterised by a positive family history (e.g., first-degree relatives with colorectal cancer or adenomatous polyps) without a single-gene defect.
The remaining ~65% is sporadic, driven mainly by ageing but also lifestyle factors such as diet, obesity, alcohol, and smoking.<tt>1012</tt>
Researchers can estimate the extent to which each risk factor contributes to the incidence of colorectal cancer; this is known as population attributable risk (PAR%).<tt>1004</tt>
Although, in the UK, females tend to eat slightly less fibre than men, many sources of data on UK population show men eat more processed meat, eat more red meat (lamb, pork, and beef), drink more alcohol and smoke more tobacco than women.<tt>1003</tt><tt>1007</tt>
Despite this, current data indicates overall intake of red meat (lamb, pork, beef) is declining. However, only 57% of men adhere to the UK recommendation of limiting red meat and processed meat to ≤70 g/day, compared to 74% of women who meet the UK recommendation. <tt>1006</tt>
Figure 3 demonstrates that low dietary intake of fibre poses the biggest risk to both males and females for developing colorectal cancer (CRC).
4. Deprovision Related Trends
People living in the most deprived areas in England have an increased risk of colorectal cancer.<tt>1001</tt>
The UK government quantifies demographic deprovision using data across seven weighted domains—income, employment, education and skills, health and disability, crime, barriers to housing and services, and the living environment. <tt>1010</tt>
The totality of all weighted domains produces a score, also known as the <u>‘Index of Multiple Deprivation (IMD)’</u>. Based on this score, areas of the UK are then ranked into quintiles for analysis in public health and research to identify inequalities, allocate resources, and track patterns in disease incidence, healthcare access, and outcomes.
Figure 4 illustrates the rate of colorectal cancer (CRC) per 100,000 per quantile, which is consistently higher in the 1st quintile (most deprived) compared to the 5th quintile (least deprived), with the latter also remaining below those of the 2nd, 3rd, and 4th quintiles.
There are several reasons why this may be; one of the intriguing and potentially actionable reasons is the lower engagement with screening programmes in deprived quintiles compared to less deprived quintiles. <tt>1013</tt>
A 2023/2024 report by the Department of Health and Social Care indicates a 20% decrease in the uptake of invitations to bowel cancer screening programmes in the least deprived quintile. This trend was seen to be consistent across all NHS regions.
The Ministry of Housing, Communities and Local Government has an interactive map which displays the quantile score for local areas in the UK. Click on the link in the tooltip to see how your region compares relatively to other regions in the UK.<tt>1011</tt>
5. Ethnicity Related Trends
Some ethnic groups, though not all, are being diagnosed with colorectal cancer (CRC) at a younger age (early-<u>onset</u> colorectal cancer (CRC)) and a relatively later stage of disease progression (late-<u>stage</u> colorectal cancer (CRC)) than white ethnic group.<tt>1008</tt>
A higher proportion of early-stage colorectal cancer (CRC) was observed in the white (39.9%) and Asian (38.8%) race groups relative to the Black (34.9%) and 'unknown' (33.4%) race groups.
Late-stage tumours (stage IV) were significantly more common among individuals from the Black, mixed and multiple and other race groups than the white ethnic group.
Interestingly, late-stage tumours (stage IV) were also significantly less common among individuals from the Asian ethnic group when compared with the white ethnic group.
Metastatic disease (stage IV) was present at diagnosis in over a quarter of individuals in the Black (28.5%), mixed/multiple (28.8%) and other ethnic groups (25.8%) compared with the White race group (22.9%).
The disparity could be explained by socioeconomic deprivation disproportionately affecting non-white race groups.
However, the researchers highlighted that symptoms of colorectal cancer (CRC) are heavily influenced by tumour sites, and some tumour sites are more common in some race groups than others, indicating a genetic component and could affect when and how symptoms present.
It happens to be for reasons not entirely clear that right-sided colorectal tumours are more common in the Black ethnic group than left-sided colorectal tumours. While tumours of the rectum are relatively more common in Asian ethnic groups than tumours of other sites. <tt>1009</tt>
Right-sided tumours are associated with a higher risk of emergency diagnosis (often reflecting later-stage diagnosis), while tumours of the rectum are associated with a lower rate of emergency diagnosis.
Conclusion
In conclusion, colorectal cancer continues to pose a significant and evolving public health burden worldwide.
While improvements in screening, early detection, and treatment have contributed to declining mortality in some regions, rising incidence—particularly among younger populations—remains a growing concern.
Persistent disparities related to age, sex, socioeconomic deprivation, and ethnicity underscore the need for targeted prevention strategies and equitable access to healthcare services.
Strengthening screening uptake, addressing modifiable lifestyle risk factors, and improving awareness across all demographic groups will be essential to reducing future incidence and improving outcomes for colorectal cancer.