Generational shifts and temporal trends in ovarian cancer burden in Spain, 1999–2023

Background Ovarian cancer remains a major cause of cancer mortality, but contemporary nationwide evidence from Spain is limited. Methods We conducted an ecological time-trend study of ovarian cancer incidence and mortality in Spain (1999–2023). Mortality counts came from the Spanish National Statistics Institute (INE) and incidence counts from the Global Burden of Disease Results Tool. Trends were assessed with joinpoint regression. Age, period and cohort effects were examined using age–period–cohort modelling with the intrinsic estimator to obtain estimable functions. Results Incident cases rose by 20.5% and deaths by 37.0%, with the largest absolute increases among women aged ≥ 85 years (deaths + 126%). Age-standardized incidence rates declined from 15.23 to 12.52 per 100,000 woman-years and mortality rates from 8.45 to 7.65. Joinpoint analysis showed a significant incidence decline from 2003 to 2017, after which no statistically significant change was detected (2017–2023: APC − 0.2%, 95% CI − 1.0 to 0.5); mortality declined steadily. Age–period–cohort modelling revealed significant non-linear cohort deviations and a declining cohort rate-ratio function across successive generations (0.38 for incidence and 0.18 for mortality in the youngest, least precisely estimated cohorts). Local drifts were negative at all ages for incidence and predominantly negative for mortality. Non-linear period deviations were modest for incidence and not significant for mortality. Conclusions Ovarian cancer incidence and mortality in Spain declined from 1999 to 2023, a pattern most consistent with favourable birth-cohort effects. The absolute burden continues to rise in the oldest women, supporting continued surveillance and improved geriatric oncology care. Key messages What is already known on this topic. Previous Spanish studies suggested that ovarian cancer mortality stabilized during the late 1990 s, with declines occurring later than in other Western European countries. However, contemporary nationwide analyses extending into the era of modern maintenance therapies and the COVID-19 pandemic have been lacking. What this study adds. This nationwide study shows an overall decline in age-standardized ovarian cancer incidence and mortality in Spain between 1999 and 2023. Age–period–cohort analyses identified a declining cohort rate-ratio function across successive generations together with modest period-related patterns. Despite declining age-standardized rates, the absolute number of deaths among women aged ≥ 85 years more than doubled over the study period, highlighting the growing impact of population ageing. How this study might affect research, practice or policy. The findings support continued surveillance of ovarian cancer trends and reinforce the need to adapt healthcare services to an ageing population. Future research should evaluate the long-term impact of demographic change, evolving reproductive patterns, advances in treatment, and the COVID-19 pandemic on ovarian cancer burden.