Caveolin-1 Expression in Upper Tract Urothelial Carcinoma

Background: Improvement in postoperative risk stratification of upper tract urothelial carcinoma (UTUC) is required to better predict outcomes and counsel patients on adjuvant treatment. Objective: To validate the association between caveolin-1 and oncological outcomes in patients treated with radical nephroureterectomy (RNU) for UTUC. Design, setting, and participants: Caveolin-1 expression was evaluated via immunochemistry on a tissue microarray from 621 patients. Caveolin-1 was considered overexpressed when at least 50% of the tumor cells stained positive. The median follow-up in this retrospective study was 35 mo (interquartile range 16-65). Intervention: Radical nephroureterectomy. Outcome measurements and statistical analysis: Univariate and multivariable Cox proportional hazards regression models were used to assess the association between caveolin-1 expression and recurrence and cancer-specific mortality (CSM). Results and limitations: Caveolin-1 was overexpressed in 150 patients (24%). Overexpression was associated with higher pathological stage (p< 0.001) and grade (p< 0.001). In univariate analyses, overexpression of caveolin-1 was significantly associated with lower recurrence (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.2-2.6; p = 0.004) and CSM (HR 1.8, 95% CI 1.2-2.7; p = 0.005); however, multivariable analyses did not prove its independent association with outcomes. The study is limited by its retrospective nature. Conclusions: Despite overexpression in a quarter of UTUC patients, caveolin-1 was not independently associated with oncological outcomes. Its use could be evaluated to improve clinical staging of biopsy specimens and to help in clinical decision-making regarding a kidney-sparing approach or neoadjuvant systemic treatment. Patient summary: Development of a panel of prognostic and predictive markers is mandatory for patient consultations in the era of personalized medicine. We evaluated the role of caveolin-1 in a large series of patients treated with radical nephroureterectomy for upper tract urothelial carcinoma (UTUC) and found that it was not independently associated with oncological outcomes. Nevertheless, it was associated with adverse pathological features. Considering caveolin-1 in UTUC biopsy specimens could help in improving clinical staging and decision-making regarding a kidney-sparing approach or neoadjuvant systemic treatment. Caveolin-1 is associated with worse oncological features among patients treated with radical nephroureterectomy for upper tract urothelial carcinoma (UTUC), but is not independently associated with oncological outcomes. Its clinical use could be explored in UTUC biopsy specimens for improving clinical staging and helping in decision-making regarding a kidney-sparing approach or neoadjuvant systemic treatment.