# Trends in Survival and Mortality of “Early” Metastatic Breast Cancer in Northern Italy Following the Introduction of Targeted Therapies

## TL;DR

In Northern Italy, fewer women are diagnosed with early metastatic breast cancer, and more are surviving due to better screening and targeted treatments.

## Contribution

The study provides real-world evidence linking improved screening and targeted therapies to declining early metastatic breast cancer incidence and better survival rates.

## Key findings

- The proportion of early metastatic breast cancer cases dropped from 6.4% in 2000–2003 to 3.8% in 2019–2022.
- One- and three-year survival rates improved significantly over the study period.
- Two-year mortality decreased by 7.3% annually after 2017.

## Abstract

Breast cancer is the most common cancer among women, and its outcome largely depends on how early it is detected and how effectively it is treated. This study examined how the number of women diagnosed with metastatic breast cancer, and their chances of survival, have changed over the past two decades in the province of Reggio Emilia, Northern Italy. The region benefits from organized mammography screening and widespread access to modern, targeted treatments. The results show that fewer women are now diagnosed with “early” metastatic disease and that survival after diagnosis has improved. These findings demonstrate how the combination of early detection and advances in precision medicine can significantly improve outcomes for women with breast cancer, providing real-world evidence that progress in both screening and therapy is saving lives in the community.

Background/Objectives: In high-income settings, the incidence of metastatic breast cancer (MBC) at diagnosis has declined, reflecting the impact of effective screening and therapeutic advances. This study examined long-term trends in MBC incidence, mortality, and survival in a province of North Italy, an area characterized by high screening participation and broad access to modern systemic treatments. Methods: All invasive breast cancer cases (n = 10,966) diagnosed between 2000 and 2022 were retrieved from the Reggio Emilia Cancer Registry (population: 532,000). Metastatic cases were defined “early” if distant metastases occurred within six months of diagnosis. Mortality trends were assessed using joinpoint regression to estimate annual percentage changes (APCs). One-, three-, and five-year survival probabilities were calculated, with follow-up through December 2024. Results: Overall, 511 cases (4.7%) were “early” metastatic breast cancers at diagnosis. This proportion declined from 6.4% in 2000–2003 to 3.8% in 2019–2022. One-year mortality decreased from 38.4% to 26.7% (APC = −6.6; 95% CI −13.1 to −0.5), and two-year mortality from 54.5% to 34.9% (APC = −7.3; 95% CI −12.3 to −1.4) after 2017. One- and three-year survival increased from 63% to 66% and from 39% to 42%, respectively, while five-year survival improved from 21% to 30%. Conclusions: Over more than two decades, the incidence of MBC at diagnosis and early mortality both declined, accompanied by improved survival. These trends temporally coincide with the widespread adoption of targeted therapies and sustained high screening coverage, suggesting a possible combined contribution of early detection and advances in precision medicine to the observed outcomes.