# Female Reproductive Cancers and the Sex Gap in Survival

## TL;DR

This study finds that female reproductive cancers, like breast and gynecological cancers, reduce women's survival advantage over men, especially between ages 35 and 60.

## Contribution

The study quantifies for the first time how female reproductive cancers specifically contribute to the narrowing of the female survival advantage over males.

## Key findings

- Females aged 35-60 consistently had higher cancer mortality than males, mainly due to breast and gynecological cancers.
- Eliminating female reproductive cancers could increase the female survival advantage by an average of 0.77 years.
- The impact of reproductive cancers on survival varied by country, with the largest gains in Ireland and smallest in Japan.

## Abstract

This cohort study quantifies differences in survival over time between males and females and examines how female reproductive cancers are associated with these differences.

What is the estimated contribution of female reproductive cancers to the differences in survival between females and males?

In this cohort study of 264.4 million deaths in 20 countries between 1955 to 2020, successive cohorts of females born since the 1930s consistently experienced higher cancer mortality rates than males between ages 35 and 60 years. This female disadvantage was primarily associated with reproductive cancers, particularly breast and gynecological cancers.

These findings suggest that female reproductive cancers attenuate total survival among females, including their advantage over males.

On average, females live longer than males. Research on sex differences in longevity has traditionally focused on higher mortality among males; however, the contribution of female reproductive cancers to survival gaps between females and males remains insufficiently quantified.

To assess the female-to-male survival gaps by estimating the contribution of age, birth cohort, and cause of death to sex differences in survival, with a particular emphasis on female reproductive cancers—breast and gynecological cancers—in long-term longevity disparities.

This cohort study used population-level mortality data from 20 countries with complete records from 1955 to 2020 from the Human Mortality and World Health Organization Mortality Databases. Data were analyzed from January 2023 to September 2025.

Geographic location (Australia, Austria, Belgium, Canada, Denmark, Finland, France, Hungary, Ireland, Italy, Japan, the Netherlands, New Zealand, Norway, Portugal, Spain, Sweden, Switzerland, the UK, and the US).

The primary outcome was the truncated cross-sectional average length of life (TCAL), which incorporates historical mortality information for all birth cohorts alive at a given time. For each country, the sex gap in survival—measured as the difference in TCAL between females and males—was calculated, decomposed, and presented graphically by birth cohort, age, and calendar year.

The analysis encompassed 264.4 million deaths from all causes (119.1 million female [45.1%]; 145.2 million male [54.9%]), including 11.5 million deaths from female reproductive cancers. The sex gap in TCALs ranged from 8.31 (95% CI, 8.28-8.34) years in Hungary to 4.22 (95% CI, 4.20-4.25) years in the Netherlands. Across all countries, females had a survival advantage for major causes of death, except for neoplasms at reproductive ages. In most populations, females aged between 35 and 60 years experienced a consistent cross-cohort excess in cancer mortality compared with males, mainly due to breast cancer and, to a lesser extent, gynecological cancers. Eliminating female reproductive cancers would increase the survival of females and expand the sex gap in TCALs by an estimated mean of 0.77 (95% CI, 0.75-0.78) years, ranging from 0.96 (95% CI, 0.92-1.00) years in Ireland to 0.51 (95% CI, 0.50-0.52) years in Japan.

In this population-level cohort study of 20 low-mortality countries, females aged 35 to 60 years experienced disadvantage in cancer mortality compared with males—a consistent pattern observed across birth cohorts and over time. These findings underscore the ongoing need for action on the prevention, early detection, and treatment of early-onset female reproductive cancers.