Understanding age and sex differentials in cancer incidence and mortality: An international population‐based study

Abstract Most epidemiologic analyses of male‐to‐female (M:F) ratios for cancer incidence have done so to gain aetiological understanding, focusing on age‐standardized M:F rate ratios for specific cancer sites. None have quantified the extent and timing, with respect to age, of sex differentials in the total cancer burden (all sites excluding non‐melanoma skin cancer). In the present study, using data from IARC's Cancer Incidence in Five Continents for 2013–17 ( N = 60 countries) and GLOBOCAN mortality 2022 ( N = 69), we estimated ages when the sex ratios peaked and reversed from a male to a female excess, or vice versa. Across all countries included, a common 4‐period pattern was observed. For incidence, period 1 featured an early‐life male excess up to age 21 years (region‐specific means ranged from 18– to 24), followed by a period 2 multi‐fold female excess lasting until age 59 (56–65) and peaking at a F:M of 2.4:1 (2.0–2.9) at age 41 (39–47), then period 3 with a large male excess peaking at M:F of 1.5:1 (1.2–1.6) at 73 (69–85) years. For the absolute burden alone (not rates) countries with long life expectancies experienced a 4th period of a female excess of cancers/cancer deaths at ≥85 years. These patterns were also present for mortality, but with a shorter period 2 duration. In summary, this study characterizes the four age periods of alternating sex differentials in the cancer burden, providing essential information to support sex‐appropriate allocation of cancer prevention and oncology resources.