Not only a Western world issue: Cancer incidence in younger individuals in the United Arab Emirates

Abstract

Two important reports regarding cancer incidence in the United States¹ and globally² have been recently released. In summary, almost 20 million people worldwide were diagnosed with cancer in 2022, and almost 10 million died of their disease.² Lung cancer is the most common cancer globally, followed by female breast, colorectal, prostate, and stomach cancers. For women, breast cancer is the most common and is most often fatal; whereas, for men, the most common is lung cancer.² Cancer statistics from the United States released late last year indicated an alarming trend which was not covered in the global statistics: that colorectal and cervical cancers are increasing among individuals younger than 50 years and that colorectal cancer is now the first cause of cancer death among men and the second cause among women in this age group.¹ This is not an observation restricted to the United States; although the data are not as robust, increases in young-onset colorectal cancer have been documented from Chennai (India) to Korea.³ Siegel et al. reported that, for three countries in Europe (Netherlands, Cyprus, and Norway), the increase in colorectal cancer incidence was twice as rapid as that in older adults.³ Still, data are sparse when it comes to the Middle East and North African nations.

Recent reports from the United Arab Emirates (UAE) demonstrate that the issue is indeed global. The UAE National Cancer Registry (UAE-NCR) records cancer incidence rates stratified by age, sex, nationality (Emirati citizens vs. non-Emirati residents), and primary cancer site. The latest report published in February 2024 included all malignant and in-situ cases diagnosed in the UAE during the year 2021.⁴ Data were collected by registry staff at the Ministry of Health and Prevention and through focal points from stakeholders across the UAE (Department of Health Abu Dhabi central cancer registry, Dubai Health Authority central cancer registry, public and private hospitals [using codes from the International Classification of Diseases, Tenth Revision and International Classification of Diseases for Oncology], medical professionals, and pathology laboratories) through a standardized form and according to recommendations of the International Agency for Research on Cancer.⁴

Although the incidence rate for the most common cancers in the UAE are at or below global averages in countries with a high/very high Human Development Index, and although the age-specific incidence rates follow predicted trends and increase with advancing age across most cancers, a notable clustering of colorectal cancer incidence at early ages is similarly observed in the latest 2021 UAE-NCR report, which is consistent with available reports since 2014 from the same national registry.⁴ For instance, in total, 82 of 532 colorectal cancers (15.4%; 13.1% in Emiratis vs. 16.3% in non-Emiratis) occurred in patients younger than 40 years, whereas 107 colorectal cancers (20.1%: 8.1% in Emiratis vs. 25.2% in non-Emiratis) occurred in patients between ages 40 and 49 years.⁴

It is alarming to note that our population, although mixed between Emiratis and non-Emiratis, reflects other concerning trends among young people (Table 1).⁴ In the UAE, 25.4% of all cancer cases were diagnosed in patients younger than 40 years, with a similar range of 20%–30% observed across both men and women and in Emirati and non-Emirati patients. The peak frequency of cancer cases was in the group aged 40–44 years in the overall population and in both Emirati and non-Emirati women, whereas the peak was in a younger age group in non-Emirati men (aged 55–59 years) compared with Emirati men (aged 70–74 years).⁴ In total, 236 of 1139 breast cancers (20.7%: 17.4% in Emiratis vs. 21.5% in non-Emiratis) occurred in patients younger than 40 years, whereas 407 breast cancers (35.7%; 25.2% in Emiratis vs. 38.2% in non-Emiratis) occurred in patients between ages 40 and 49 years.⁴ By comparison, only 4% of breast cancers in the United States occurred in patients younger than 40 years, and 13% occurred in patients between ages 40 and 49 years.⁵ Similarly, in total, 293 of 595 thyroid cancers (49.2%; 50.3% in Emiratis vs. 48.8% in non-Emiratis) occurred in patients younger than 40 years, whereas 169 (28.4%; 25.9% in Emiratis vs. 29.6% in non-Emiratis) occurred in patients between ages 40 and 49 years.⁴

This may be primarily attributed to the UAE being a young nation populated mostly by expatriate, young residents. The median age of the UAE population, according to 2021 data, was approximately 30 years overall.⁶ In fact, the age-specific incidence rates for breast cancer among women illustrated in the 2021 UAE-NCR report are comparable to those reported in the United States; they rise steadily from age 25 years, cross the 100 per 100,000 threshold between ages 40 and 49, and peak at ages 70–74 years.^{4, 5} Therefore, one cannot assume an increased risk of developing cancer in young individuals in the UAE compared with other countries but, rather, a higher percentage of cancer cases in this age group. Nonetheless, and looking at the absolute rather than the relative risk, having such a high burden of cancer in younger age groups stresses the need for understanding risk factors for early onset disease that can inform optimal (early) screening and preventive strategies.^{7, 8}

The prevalence of obesity and overweight in the UAE youth is high, similar to other Arab countries facing increased consumption of unhealthy diets with poor nutritional benefits. Obesity and smoking (including all forms) have been prioritized on the UAE public health agenda, with multiple initiatives to control them. Several efforts to optimize the uptake of gender-neutral human papillomavirus vaccination and to mandate hepatitis B vaccination in high-risk groups have also been launched in the past 2 decades.⁷ Further research into the roles of other risk factors, such as the unique genetic admixture in a country highly populated by expatriates, cultural habits, environmental risks, and the microbiome, are called for to shed better light on cancer epidemiology in the UAE, and various projects have been recently launched with this objective, including the Emirati Genome Program.

The study of cancer incidence in young individuals must be global, with contributions from various nations and regions, so all can benefit from research outcomes with potential impact on screening guidelines and policy.

The authors disclosed no conflicts of interest.