Why are more younger adults in the Eastern Mediterranean facing colorectal cancer?

by · News-Medical

A 22-country analysis reveals striking differences in early-onset colorectal cancer incidence, mortality, and future burden across a rapidly changing region.

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In a recent study published in The Lancet Regional Health - Eastern Mediterranean, researchers investigated region-specific patterns in the epidemiology and burden of early-onset colorectal cancer (EO-CRC), focusing on the World Health Organization (WHO) Eastern Mediterranean Region (EMRO).

The study used modeled population-based surveillance estimates from the Global Cancer Observatory (GLOBOCAN) 2022 database (22 countries) to estimate the current epidemiological burden, temporal trends, and future projections of EO-CRC.

Study findings revealed that in 2022 alone, EMRO recorded 15,381 new cases of EO-CRC (age-standardized incidence rate [ASIR] = 2.5 per 100,000 population) and 6,965 related deaths (age-standardized mortality rate [ASMR] = 1.1 per 100,000 population). These figures represented 28.5% of all colorectal cancer diagnoses and 23.3% of total colorectal cancer deaths.

The analyses found that while EMRO had intermediate incidence rates relative to other WHO regions, it experienced one of the highest EO-CRC mortality rates.

The authors said this pattern supports earlier detection and context-specific screening strategies, including considering lower screening ages in higher-burden settings, as well as improved access to diagnosis and cancer care.

Background

Colorectal cancer (CRC) is an umbrella term for malignancies afflicting cells of the large intestine (“colon”) or the rectum. Public health records have identified CRC as the third most commonly diagnosed cancer worldwide and the second leading cause of cancer-related death, with estimates finding these diseases responsible for approximately 1.9 million new cases and 904,000 deaths in 2022 alone.

CRC has historically been viewed as a disease predominantly affecting older individuals. In recent decades, evidence has documented a rise in diagnoses among people under age 50, a condition termed early-onset colorectal cancer (EO-CRC).

Previous research has proposed several possible contributors to the rise in EO-CRC, including changes in dietary patterns, antibiotic exposure, rising obesity, sedentary lifestyles, and alterations in the gut microbiome.

Reviews from the field also report that the bulk of these datasets and epidemiological reports are derived from Western countries, with very limited and fragmented regional data from the Eastern Mediterranean.

Until now, no comprehensive multi-country assessment had examined whether socioeconomic development was associated with EO-CRC outcomes across EMRO.

About the study

The present study aimed to address this knowledge gap and inform oncological public health policy within the Eastern Mediterranean region by characterizing the epidemiology of EO-CRC, defined as CRC diagnosed before age 50, across all the World Health Organization (WHO) Eastern Mediterranean Region (EMRO) member states (n = 22).

The dataset comprised estimates of incidence, mortality, and prevalence obtained from the International Agency for Research on Cancer (IARC) GLOBOCAN 2022 database. Researchers compared these EMRO regional metrics against global baselines and other WHO jurisdictions, including the European Region (EURO), the Region of the Americas (PAHO), and the African Region (AFRO).

Primary objectives included describing age-specific incidence and mortality rates across age groups (ages 0–19, 20–34, and 35–49 years). Historical incidence trends were assessed where longitudinal data were available, which were limited to Bahrain, Kuwait, and Qatar, using the estimated annual percentage change (EAPC) metric.

The Human Development Index (HDI) was used to assess the relationship between national development and cancer burden. Finally, the authors modeled disease projections through 2050 using the Cancer Tomorrow platform.

Study findings

Analyses revealed that in 2022, EO-CRC incidence and mortality were highest among adults aged 35 to 49 years (age-standardized incidence rate [ASIR] = 8.4 per 100,000 population; age-standardized mortality rate [ASMR] = 3.7 per 100,000). Jordan had the highest regional incidence rate (ASIR = 4.2 per 100,000), followed by Libya (ASIR = 3.5 per 100,000) and Iran (ASIR = 3.3 per 100,000).

The United Arab Emirates (UAE) reported an ASIR of only 0.69 per 100,000 individuals, highlighting substantial geographical variation among EMRO member states. Mortality also varied widely, with Jordan reporting an ASMR of 1.9 per 100,000.

Temporal analyses revealed that between 2013 and 2017, incidence rates accelerated rapidly in Kuwait (EAPC = 7.67%) and Qatar (EAPC = 17.53%). The analyses also identified an exploratory inverse association between HDI and EO-CRC mortality, with lower-HDI countries tending to have higher mortality rates. The Pearson correlation was statistically significant, but the Spearman correlation was not, so the authors advised a cautious interpretation.

Projection modeling estimated that regional EO-CRC cases could rise by about 58.6%, from 15,381 in 2022 to 24,396 annual diagnoses by 2050, with deaths rising from 6,965 to 11,005. These projected increases in counts are driven by demographic change, assuming constant age-specific rates, rather than by a forecast that underlying EO-CRC rates will rise by the same amount.

The modeling also showed substantial geographic disparities in the regional burden of EO-CRC, with countries such as Somalia, Afghanistan, and Yemen projected to experience increases in EO-CRC case counts exceeding 100%.

The authors cautioned that the ecological study design cannot establish causation and that differences in cancer registration and mortality data quality across EMRO countries may affect the estimates.

Conclusions

The present study identifies early-onset colorectal cancer as a growing public health burden in the EMRO, highlighting socioeconomic disparities and supporting context-specific cancer control strategies.

The authors suggest that high-burden, high-HDI countries consider lower population screening ages alongside risk-stratified approaches; medium-HDI settings strengthen organized screening and referral pathways; and low-HDI countries prioritize awareness, affordable access to diagnostics and screening, and cancer registry capacity rather than broad, resource-intensive screening programs.

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