# Population-based analysis of breast cancer incidence and mortality: overall and age-specific temporal trends over 40-year period in Girona, Spain

## TL;DR

This study analyzed breast cancer trends in Girona, Spain from 1980 to 2019, finding a rise in incidence followed by stabilization and a decline in mortality, likely due to screening and treatment advances.

## Contribution

The study provides a detailed 40-year population-based analysis of breast cancer incidence and mortality trends in a specific region, highlighting the impact of screening and treatment.

## Key findings

- Breast cancer incidence increased significantly from 1980 to 1994, then stabilized.
- Mortality rates declined significantly since 1992, likely due to screening and treatment.
- Age-specific trends showed different patterns in women over 69 compared to younger age groups.

## Abstract

Breast cancer (BC) incidence and mortality in women have changed over time. This study aims to analyze population-level incidence and mortality trends over 40 years of observation.

Population-based study of BC conducted by Girona Cancer Registry covering the period 1980–2019. Age-standardized incidence and mortality rates were calculated. Poisson change-point regression models were used to analyze trends, calculating the annual percentage change (APC).

A total of 12,283 diagnoses of invasive BC between 1980 and 2019. The overall age-standardized incidence rate was 109.9 (95% confidence intervals (CI) 104.4; 115.4) cases per 100,000 women-years. Trend analyses showed a statistically significant incidence increase of 4.2% per year from 1980 to 1994 (95%CI 3.3; 5.1), and a stabilization between 1994 and 2019, with an APC of 0.28% (95%CI − 0.04; 0.56). These trends were similar for the age groups 0–49 years and 50–69 years. In women over 69 years of age, an increase in incidence of 4.4% (95%CI 2.8; 6.0) per year was observed between 1980 and 1995 followed by a non-statistically significant decrease of − 0.35% (95%CI − 0.86; 0.15) between 1995 and 2019. The overall age-standardized mortality rate was 30.3 (95%CI 29.3; 31.3) cases per 100,000 women-years. Mortality rate trends showed a statistically significant decrease of − 1.87% (95%CI − 2.38; − 1.37) per year since 1992.

There has been a stabilization in the incidence of BC and a gradual decline in BC mortality in women. The introduction of mammography in the mid-1990s, alongside early detection and treatment due to screening programs may play a significant role in the reduction of BC burden in women of all ages.

The online version contains supplementary material available at 10.1007/s10549-025-07704-8.