The Prognostic Role of HER2 Expression in Patients With Non-Muscle-Invasive Bladder Cancer

Area of Science:

• Oncology
• Urology
• Molecular Pathology

Background:

• Current risk stratification models for non-muscle-invasive bladder cancer (NMIBC) lack sufficient predictive efficiency.
• There is a need for improved prognostic markers to better predict recurrence in NMIBC.

Purpose of the Study:

• To assess the relationship between human epidermal growth factor receptor 2 (HER2) expression status and tumor recurrence in NMIBC patients.
• To evaluate the added prognostic value of HER2 expression to established risk stratification models.

Main Methods:

• Retrospective analysis of 217 NMIBC patients treated with transurethral resection.
• Immunohistochemistry (IHC) used to categorize HER2 expression as high (2⁺/3⁺) or low (0/1⁺).
• Cox regression analysis and concordance index (C-index) employed to assess recurrence-free survival (RFS) and model performance.

Main Results:

• High HER2 expression was significantly associated with pT1 stage, high tumor grade, and increased recurrence rates.
• High HER2 expression was identified as an independent predictor of recurrence (HR 2.58, P = .002).
• Integration of HER2 status significantly improved the predictive performance of the European Organization for Research and Treatment of Cancer (EORTC) and Club Urológico Español de Tratamiento Oncológico (CUETO) models.

Conclusions:

• High HER2 expression is a significant independent predictor of recurrence in NMIBC.
• HER2 status provides incremental prognostic value beyond current EORTC and CUETO risk scores.
• HER2 expression enhances risk stratification, particularly within intermediate- and high-risk European Association of Urology (EAU) groups.