Oncotype DX Recurrence Score Predicts Survival in Invasive Micropapillary Breast Carcinoma: A National Cancer...

Area of Science:

• Oncology
• Genomics
• Breast Cancer Research

Background:

• Invasive micropapillary carcinoma (IMPC) is a rare, aggressive breast cancer subtype with high metastasis rates.
• The prognostic utility of Oncotype DX recurrence score (RS) in IMPC, a histology with distinct biology, is unvalidated.
• This study assesses the prognostic value of Oncotype DX for overall survival (OS) in early-stage IMPC.

Purpose of the Study:

• To evaluate the Oncotype DX recurrence score (RS) as a prognostic indicator for overall survival (OS) in patients with invasive micropapillary carcinoma (IMPC).
• To determine if RS can refine adjuvant treatment decisions, including radiation therapy, in this specific breast cancer subtype.

Main Methods:

• Utilized the National Cancer Database (2004-2020) to identify 1325 women with ER+/HER2-, T1-T2N0-N1 IMPC who underwent Oncotype DX testing.
• Stratified patients by RS (low ≤11, intermediate 12-25, high >25) and compared 5-year OS using Kaplan-Meier curves and log-rank tests.
• Employed multivariable Cox proportional hazards models to assess RS as an independent predictor, adjusting for clinical and demographic factors.

Main Results:

• Significant survival differences were observed across RS groups (log-rank p = 0.017), with 5-year OS rates of 97.5% (low), 97.5% (intermediate), and 93.7% (high).
• Adjusted analysis confirmed RS as an independent prognosticator: low (HR=0.31) and intermediate (HR=0.32) RS correlated with reduced mortality versus high RS.
• Omission of radiation therapy (HR=2.68) and higher comorbidity burden (HR=0.25 for ≥2 vs. 0) were associated with worse survival.

Conclusions:

• Oncotype DX recurrence score (RS) is a validated prognostic tool for overall survival (OS) in invasive micropapillary carcinoma (IMPC).
• High RS (>25) is associated with poorer outcomes, supporting its use in guiding adjuvant therapy decisions for IMPC.
• Findings suggest potential for RS-driven personalization of adjuvant radiation and comorbidity management to improve outcomes in IMPC.