Background: Muscle-invasive urothelial carcinoma of the bladder is a highly lethal malignancy, particularly in the setting of locally advanced or metastatic disease. Prior reports of HER2/neu (c-erbB-2 or HER2) expression in bladder carcinoma have been mixed; therefore, its value in predicting metastasis or response to therapy has not been established in this tumor type. Thus, the authors evaluated a possible correlation between HER2 expression in patients with high-grade, muscle-invasive urothelial carcinoma of the bladder and outcome in patients who received paclitaxel-based chemotherapy.
Methods: Archival tumor tissues from patients with advanced urothelial carcinoma who were enrolled on two clinical trials of paclitaxel-based chemotherapy regimens were analyzed for HER2/neu expression by immunohistochemistry (IHC). The authors correlated HER2 expression by IHC with clinical outcomes, such as response rate, progression free survival, and overall survival, using univariate analysis.
Results: Thirty-nine tumor specimens were assessed for HER2 expression, most of which (70%) were collected from patients with metastatic disease. All were high-grade urothelial carcinomas (transitional cell carcinomas, Grade 3). Strong HER2 expression (2+/3+) was seen in 28 patients (71%). Patients with responding disease had an HER2 expression rate of 78%, similar to the rate seen in patients with stable disease (75%). In contrast, patients with progressive disease had an HER2 expression rate of 50%, although this difference did not reach statistical significance. However, univariate analysis showed that increased HER2 expression predicted an improvement in progression free and overall survival. When HER2 status was used as a dichotomous variable, tumors with positive HER2 expression did not have any association with response or with progression free survival; however, positive HER2 status was associated significantly with a decreased risk of death (P = 0.03).
Conclusions: This study of HER2 expression in bladder carcinoma focused on patients who were treated prospectively in a standardized fashion, unlike prior studies that have evaluated banked, archival specimens. The authors confirmed the findings of others that high-grade, muscle-invasive urothelial carcinoma of the bladder has a significant rate of HER2 expression (71%). However, contrary to other reports, the current study found that HER2 expression in the context of paclitaxel-based chemotherapy decreased the risk of death significantly. Further research is warranted on the possible association of HER2 expression with chemosensitivitiy in urothelial carcinoma as well as the efficacy of HER2-targeted therapies (such as trastuzumab) for patients with high-grade, muscle-invasive urothelial carcinoma of the bladder.
Copyright 2002 American Cancer Society.