Prognostic Value of Variant Histology in Upper Tract Urothelial Carcinoma Treated with Nephroureterectomy: A Systematic Review and Meta-Analysis

Abstract

Purpose: This systematic review and meta-analysis aimed to assess the prognostic value of variant histology in patients with upper tract urothelial carcinoma (UTUC) treated with radical nephroureterectomy. Material and Methods: The PUBMED, Web of Science, Cochrane Library, and Scopus databases were searched in May 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. Studies were deemed eligible if they compared overall, cancer-specific, and recurrence-free survival in UTUC patients with and without variant histology. Formal meta-analyses were performed for these outcomes. Results: The review identified 32 studies with 16,052 patients, including 26 studies and 12,865 patients that were eligible for the meta-analysis. Variant histology was associated with poor outcomes in terms of cancer-specific survival (pooled hazard ratio [HR]: 2.00, 95% confidence interval [CI]: 1.57−2.56), overall survival (pooled HR: 1.76, 95% CI: 1.51−2.04), and recurrence-free survival (pooled HR: 1.64, 95% CI: 1.42−1.89). Subgroup analyses revealed that ‘micropapillary’ and ‘squamous and/or glandular’ variant histology were also associated with poor cancer-specific survival (pooled HR: 3.02, 95% CI: 1.71−5.34, and pooled HR: 1.48, 95% CI: 1.14−1.92, respectively). Conclusions: Variant histology in patients with UTUC is associated with an increased risk of cancer-specific mortality, overall mortality, and disease recurrence. Furthermore, variant histology was independently associated with cancer-specific survival in the ‘micropapillary’ and ‘squamous and/or glandular’ variant histology subgroups. It might be useful to incorporate variant histology into prognostic tools that help guide patients and physicians in selecting appropriate treatment strategies for UTUC.