Increasing incidence of ovarian cancer in young women in England, 1985-2019

BACKGROUND: Ovarian cancer is the 6th most common cancer in women in the UK, accounting for about 7,500 new cases and 4,100 deaths each year. Genetic predisposition and obesity are the two most important risk factors. We conducted a retrospective population-based cohort study to ascertain trends in incidence of ovarian cancer in England from 1985-2019. METHODS: Individual level data for women diagnosed with ovarian cancer, and the corresponding national population (denominator) data were obtained from ONS/PHE. Average annual incidence rates (AAIR) were calculated for 2 age categories (0-49 and 50+ years) and for the 7 five-year time periods (1985-89 to 2015-19). RESULTS: During the 35-year study period, a total of 192,791 women with ovarian cancer were registered in England. The large majority of the cases (83%) were diagnosed in women aged 50+ years. In women aged 0-49 years, there was a steady increase in the AAIRs from 4.9/100,000 in 1985-89 to 6.3/100,000 in 2015-19 (+28.6%). Whereas in older women (aged 50+ years), the AAIRs initially increased from 47.9/100,000 (1985-89) to 54.4/100,000 (2000-04), and then steadily declined to 44.6/100,000 in 2015-19. As for the stage at diagnosis, the majority of younger women (72%) were diagnosed at Stage 1 or 2, whereas the majority of older women (65%) were diagnosed at Stage 3 or 4. There was also a dichotomy with regards to socioeconomic status - in younger women the disease was relatively more commonly diagnosed in the most deprived groups, whereas in older women the disease was more commonly diagnosed in the most affluent groups. CONCLUSIONS: This study shows that from 2000 onwards, there has been a steady decline in the incidence of ovarian cancer among women aged 50+ years in England. On the other hand, the incidence rates have been steadily increasing in women aged 0-49 years during the past 35 years. The reasons for this increasing trend in the incidence of ovarian cancer in young women needs further investigation. KEY MESSAGES: • The increasing incidence of ovarian cancer in young women (aged 0-49 years) is consistent with the increasing prevalence of obesity in England. • The declining trend in incidence of ovarian cancer in women aged 50+ years needs to be examined in light of the increasing trend in incidence of HRT prescriptions for menopausal women.