Global epidemiology of epithelial ovarian cancer

Globally, ovarian cancer is the eighth most common cancer in women, accounting for an estimated 3.7% of cases and 4.7% of cancer deaths in 2020. Until the early 2000s, age-standardized incidence was highest in northern Europe and North America, but this trend has changed; incidence is now declining in these regions and increasing in parts of eastern Europe and Asia. Ovarian cancer is a very heterogeneous disease and, even among the most common type, namely epithelial ovarian cancer, five major clinically and genetically distinct histotypes exist. Most high-grade serous ovarian carcinomas are now recognized to originate in the fimbrial ends of the fallopian tube. This knowledge has led to more cancers being coded as fallopian tube in origin, which probably explains some of the apparent declines in ovarian cancer incidence, particularly in high-income countries; however, it also suggests that opportunistic salpingectomy offers an important opportunity for prevention. The five histotypes share several reproductive and hormonal risk factors, although differences also exist. In this Review, we summarize the epidemiology of this complex disease, comparing the different histotypes, and consider the potential for prevention. We also discuss how changes in the prevalence of risk and protective factors might have contributed to the observed changes in incidence and what this might mean for incidence in the future. Ovarian cancer, accounting for 4.7% of cancer deaths in women in 2020, remains highly prevalent globally. Nonetheless, owing to changes in environmental exposures, the approach to preventive measures and disease classification, both incidence and mortality have been declining in economically developed countries since the early 2000s. Conversely, parts of Asia and eastern Europe have seen increases in the incidence of ovarian cancer over this period of time. In this Review, the authors summarize the epidemiology of ovarian cancer, including the roles of the various risk factors and the potential for prevention. The disease we call 'ovarian' cancer encompasses a wide range of tumour types, including cancers that arise in the fallopian tube; changes in coding and reporting make incidence trends over the past decade difficult to interpret.Between 1920 and 1960, successive birth cohorts had lower risk of developing ovarian cancer, although incidence might be increasing again in women born after about 1970.With the recognition that high-grade serous cancers originate in the fallopian tube, salpingectomy (opportunistic or targeted) offers the opportunity for prevention and could delay the need for oophorectomy among women with a high genetic risk.Hormonally related factors, including pregnancy, oral contraceptive use and breastfeeding, reduce the risk of ovarian cancer, particularly the endometrioid and clear cell histotypes; the benefits of newer contraceptive formulations are less clear.Lifestyle exposures, including smoking, obesity and, potentially, sedentary behaviour or inactivity, all increase the risk of a woman developing the less common histotypes but do not appear to affect the risk of developing the most common high-grade serous cancers.If current trends continue, the incidence of ovarian cancer might start to increase, although widespread uptake of salpingectomy and expanded identification and interventions targeting BRCA mutation carriers have the potential to reduce incidence.