Metaplastic Breast Cancer Characteristics and Patterns of Recurrence: A Single Institution Experience

Area of Science:

• Oncology
• Pathology
• Breast Cancer Research

Background:

• Metaplastic breast cancer (MtBC) is a rare and aggressive form of breast cancer with diverse pathological subtypes.
• Limited data exists on MtBC's behavior and treatment, necessitating further investigation into its clinicopathological characteristics and outcomes.

Purpose of the Study:

• To investigate the clinicopathological characteristics of Metaplastic Breast Cancer (MtBC).
• To analyze overall survival and recurrence patterns in MtBC patients.
• To evaluate the impact of neoadjuvant chemotherapy (NACT) on MtBC outcomes.

Main Methods:

• Retrospective review of 91 MtBC patients from 2009-2024.
• Collection of patient-specific, clinicopathological, and survival data, including treatment details and recurrence information.
• Survival estimates calculated using the product-limit method; data described using frequency counts and percentages.

Main Results:

• The study population (mean age 60) was predominantly Caucasian, postmenopausal, and had a BMI >25.
• Most MtBC cases were estrogen, progesterone, and HER2 negative (triple-negative).
• Distant recurrence was common (41.4%), primarily involving the lungs, with a median time to recurrence of 12 months. NACT showed potential, with 7 patients achieving a complete pathological response (pCR).

Conclusions:

• MtBC exhibits aggressive behavior, frequently presenting as triple-negative with high Ki-67.
• Distant recurrence, particularly lung metastasis, is a significant concern, highlighting the importance of regular chest imaging.
• NACT can be beneficial for a subset of MtBC patients, achieving pCR in 25.9%; further research is warranted to establish standardized treatment protocols.