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A recent global study published in eClinicalMedicine has shed light on the evolving patterns and trends in ovarian cancer incidence across different regions and histological subtypes. The comprehensive analysis provides important insights into the global burden of ovarian cancer, revealing significant regional and ethnic disparities in incidence rates.
Global Burden of Ovarian Cancer
Ovarian cancer is the eighth most commonly diagnosed cancer and the leading cause of cancer-related death among women worldwide. In 2022, over 324,000 new cases were reported, along with 206,839 deaths. The disease’s global burden varies significantly across different geographic and ethnic groups. European and North American regions report higher incidence rates, while countries in the Caribbean and Africa have a notably lower occurrence of ovarian cancer.
Ovarian cancer is highly heterogeneous, with several histological subtypes. Epithelial ovarian cancers account for 90% of all cases, while non-epithelial ovarian cancers, including sex cord-stromal and germ cell tumors, make up the remaining 10%.
Study Design and Methodology
This study analyzed global ovarian cancer incidence trends and distributions across histological subtypes, using data from the 2024 Cancer Incidence in Five Continents (CI5) volume XII and the CI5plus databases. The researchers examined incidence data from 65 countries between 2013 and 2017 and analyzed temporal trends over 30 years, from 1988-1992 to 2013-2017. Age-standardized rates of ovarian cancer and its subtypes were calculated to assess global patterns.
Findings on Global Incidence Patterns
The study revealed striking variations in ovarian cancer incidence across different regions and socioeconomic groups. The highest age-standardized rates were seen in Eastern and Central Europe, as well as in regions with very high Human Development Indices (HDIs). In contrast, lower rates were observed in Africa, Asia, and regions with medium HDIs between 2013 and 2017.
Interestingly, the study found that age-standardized rates of ovarian cancer have been declining in Europe, North America, and Oceania, while rates have risen in certain Asian countries, such as Japan and South Korea.
Trends in Ovarian Cancer Subtypes
Serous carcinoma was identified as the most prevalent subtype of ovarian cancer in most countries analyzed, particularly in Europe, where higher age-standardized rates were reported. Mucinous carcinomas, on the other hand, were more common in several Asian nations, followed by endometrioid and clear cell carcinomas.
While the overall incidence of ovarian cancer subtypes remained stable, there was a notable increase in the prevalence of serous carcinomas and germ cell tumors in many countries. In contrast, the age-standardized rates of mucinous carcinomas and adenocarcinomas have decreased over time.
Age-Specific Incidence Trends
The study also highlighted differences in ovarian cancer incidence across age groups. Incidence rates for all subtypes remained low until women reached 35-39 years of age, with a significant increase in rates observed as age advanced. Serous carcinomas exhibited the highest incidence between the ages of 70 and 74, while adenocarcinomas peaked between 80 and 84 years.
For mucinous, endometrioid, and clear cell carcinomas, incidence rates initially rose but then decreased in older age groups. Sex cord-stromal and germ cell tumors maintained consistently low incidence rates across all age groups.
Study Significance
The study’s findings underscore the importance of understanding regional disparities in ovarian cancer incidence. Factors such as genetics, reproductive behaviors, and access to healthcare likely contribute to these differences. Notably, regions with high HDIs, which tend to have better healthcare infrastructure, reported higher incidence rates, likely due to greater health awareness and earlier cancer diagnosis.
In regions with lower HDIs, limited diagnostic resources may contribute to lower reported incidence rates. The study emphasizes the need for continued surveillance and tailored prevention strategies to address ovarian cancer’s growing global burden.
As ovarian cancer remains a significant health challenge, the study calls for greater efforts in education, early detection, and equitable healthcare to mitigate its impact worldwide.
Journal Reference:
Wei, Y., Ning, L., Xu, Y., et al. (2024). Worldwide patterns and trends in ovarian cancer incidence by histological subtype: a population-based analysis from 1988 to 2017. eClinicalMedicine. doi:10.1016/j.eclinm.2024.102983.
