IARC 60th Anniversary - 19-21 May 2026
Session : 19/05/26 - Posters
Trends in ovarian cancer incidence: overall analysis and analysis by histological subtype based on data from the Calvados General Tumor Registry
HOUNNOU T. 1,2, VIGNERON N. 1,2,3, GARDY J. 1,2,3,4, RENIER M. 1,2, LEBAILLY P. 1,2
1 ANTICIPE UMR (1086) (Interdisciplinary Research Unit for Cancers Prevention and Treatment), Federative Structure 4207 Normandie Oncologie, Université de Caen Normandie, Inserm, F-14000 , CAEN, France; 2 Comprehensive Cancer Center François Baclesse, UNICANCER, Caen, France; 3 Calvados General Tumor Registry, Comprehensive Cancer Center François Baclesse, UNICANCER, Caen, France; 4 Calvados Digestive Cancer Registry, University Hospital of Caen, Caen, France
Introduction:
Ovarian cancer is the 7th most common cancer among women worldwide counting for around 300,000 incident cancers in 2022 and with approximately 5,300 new cases diagnosed each year in France. More than 90% of ovarian cancers are epithelial carcinomas, of which approximately 60-70% are high-grade serous, 10-15% are endometrioid, 5-10% are mucinous, and 3-5% are clear cell. Internationally, incidence trends by subtype remain heterogeneous: an overall decline in epithelial, stromal, and sex cord tumors in the United States; an increase in endometrioid and clear cell carcinomas in Asia; and variations in Northern Europe, with a decline in serous tumors in Denmark and Norway. In France, studies by subtype remain limited. The knowledge of its etiology remains limited, particularly concerning environmental and occupational exposures. This study is part of a larger project on the etiology of ovarian cancers and aims to describe the evolution of the incidence of ovarian, fallopian tube, and peritoneal cancers in Calvados, considering their histological subtypes and searching for possible breakpoints.
Materials & Methods:
Age-standardized incidence rates (worldwide) were calculated for five-year rolling periods based on data from the Calvados General Tumor Registry and INSEE population estimates. Trends and breakpoints were studied using a joinpoint model from the SEER in the USA for the period 1978 to 2021 as a whole, then by epithelial subtype for the period 1988 to 2021. The annual percentage changes (APC) or average annual percentage changes (AAPC) estimated using the model were used to quantify the changes in standardized incidence rates for each sub-period and for the entire study period, respectively.
Results:
Overall, the standardized annual incidence rate of ovarian cancer increased until 2006 (CI95%: [2005; 2007]), with an initial increase between 1980 and 2002 (APC = 0.7%; p = 0.002), followed by an acceleration until 2006 (APC = 3.7%; p = 0.0008), then decreased until the end of the study period (APC = 3.1%; p < 0.001, from 2006 to 2019).
The incidence of epithelial tumors followed a similar trend to that of ovarian cancers overall, and most epithelial subtypes decreased, with the exception of high-grade serous cancers, which increased with average annual percentage changes (AAPC) ranging from 1.1% (IC95%: [0.8; 1.4]; p< 0.001) and 9.5% (IC95%: [9.2; 9.8]; p< 0.001) per year.
Discussion/Conclusion:
These departmental results reflect American trends and highlight the importance of assessing incidence by clinical entity rather than by organ. Their confirmation in other French registries, currently underway, will enable any geographical disparities to be investigated. Finally, ovarian cancer is a multifactorial tumor entity, with few proven risk factors and several suspected factors, such as occupational and environmental exposures, justifying the interest of this descriptive epidemiological study in providing etiological avenues for further exploration.