Study Highlights Changing Global Patterns In Ovarian Cancer By Region And Subtype

A recent study published in eClinicalMedicine highlights global patterns and trends in ovarian cancer incidence, focusing on its histological subtypes.

Global Burden of Ovarian Cancer

Ovarian cancer ranks as the eighth most common cancer and a leading cause of cancer-related deaths among women globally. In 2022, over 324,000 new cases and 206,839 deaths were recorded.

Geographically, significant disparities exist in ovarian cancer incidence. Regions such as Europe and North America report higher rates, while the Caribbean and Africa experience relatively lower incidences. The disease is highly diverse, with epithelial ovarian cancers constituting 90% of cases, while non-epithelial types, including sex cord-stromal and germ cell tumors, account for the remaining 10%.

Study Design

The researchers examined global patterns and trends in ovarian cancer incidence and subtypes, analyzing data from 65 countries between 2013-2017 and temporal trends from 1988-1992 to 2013-2017. The analysis relied on data from the 2024 Cancer Incidence in Five Continents (CI5) volume XII and CI5plus databases. Annual percent changes in age-standardized rates (ASRs) were calculated to assess trends.

Incidence Patterns and Trends

Substantial regional, national, and socioeconomic variations were noted in ovarian cancer incidence.

• Regions with High ASRs: Eastern and Central Europe, as well as areas with very high Human Development Indices (HDIs).
• Regions with Low ASRs: Africa, Asia, and medium HDI regions.

Between 2013 and 2017, ovarian cancer ASRs declined in Europe, America, and Oceania but rose in parts of Asia, notably Japan and South Korea.

Trends by Histological Subtypes

Serous carcinomas were the most common subtype globally, with higher rates in Europe. In Asia, mucinous carcinomas were more prevalent, followed by endometrioid and clear cell carcinomas.

Though ASRs for ovarian cancer subtypes remained relatively stable, serous carcinomas and germ cell tumors showed increased prevalence. In contrast, mucinous carcinomas and adenocarcinomas displayed declining trends.

Age-Specific Incidence

Across all subtypes, ovarian cancer incidence was consistently low until ages 35-39. Serous carcinoma rates peaked at ages 70-74, followed by a slight decline among women aged 85 and older. Similar trends were observed for adenocarcinomas, with the highest rates among women aged 80-84.

For mucinous, endometrioid, and clear cell carcinomas, incidence initially increased but later declined in specific age groups, while sex cord-stromal and germ cell tumors maintained low rates across all ages.

Study Implications

This study offers the latest insights into global patterns and trends in ovarian cancer and its subtypes. Regional and socioeconomic disparities in incidence are likely influenced by genetic factors, reproductive behaviors, and healthcare accessibility. The higher rates in very high HDI regions could reflect better diagnostic capabilities and heightened health awareness.

The findings underscore the need for ongoing ovarian cancer surveillance and tailored prevention strategies to address regional disparities and reduce the global burden of the disease.