# Prognosis of Metaplastic Breast Cancer: A Population‐Based Matched Cohort Study

## TL;DR

This study compares the survival outcomes of rare metaplastic breast cancer with common breast cancer and finds no significant difference when patients receive appropriate treatment.

## Contribution

The study provides population-based evidence on the prognosis of metaplastic breast cancer compared to no special type breast cancer.

## Key findings

- Metaplastic breast cancer was not significantly associated with worse breast cancer-specific survival.
- There was no significant difference in overall survival between metaplastic and no special type breast cancer.
- Appropriate treatment may lead to comparable survival outcomes for both cancer subtypes.

## Abstract

Metaplastic breast cancer (metBC) is a rare subtype of breast cancer known for its challenging management. The impact of this histological subtype on prognosis remains unclear.

Data were collected from the Swedish Cancer Registry between 2008 and 2018. Patients with metBC were matched 2:1 with breast cancer cases of no special type (NST). Survival outcomes were analyzed using cause‐specific hazard models for breast cancer specific survival (BCSS) and Cox proportional‐hazards models for overall survival (OS).

In total, 127 metBC patients were matched 2:1 with 245 NST patients, with a median follow‐up period of 54 months. When adjusted for matching variables and treatment‐related characteristics, metBC was not significantly associated with either BCSS (cause‐specific Hazard Ratio (HR): 1.13; 95% Confidence Interval (CI): 0.66–1.92) or OS (HR: 1.23; 95% CI: 0.83–1.82).

With appropriate treatment, metBC may have survival outcomes comparable to NST. Larger studies with longer follow‐up are needed to provide further insights.