The role of fluorescence in situ hybridization to predict patient response to intravesical Bacillus Calmette–Guérin therapy for bladder cancer: A diagnostic meta-analysis and systematic review

BACKGROUND: The aim of the study was to systematically review the relevant studies to assess the role of fluorescence in situ hybridization (FISH) test for predicting patient response to Bacillus Calmette–Guérin (BCG) therapy after transurethral resection of bladder tumor (TURBT). METHODS: We searched PubMed, Embase, and the Cochrane Library from inception to July 5, 2018, and used Quality Assessment Tool for Diagnosis Accuracy Studies (QUADAS-2) to assess the quality. We pooled sensitivity, specificity, and area under curve (AUC) of baseline and post-BCG FISH test for predicting tumor recurrence. Hazard ratio (HR) with 95% confidence intervals (95% CIs) and a Fagan nomogram were applied to assess predictive accuracy of post-BCG FISH test. RESULTS: A total of 6 studies with 442 participants for post-BCG test and 404 participants for baseline BCG test were included. The pooled analysis for post-BCG FISH test revealed the sensitivity of 0.54 (95% CI 0.38–0.69), specificity of 0.84 (95% CI: 0.72–0.91), and area under the curve (AUC) of 0.78 (95% CI: 0.74–0.81) for predicting tumor recurrence. Patients with positive post-BCG FISH test were more likely to recur during follow-up (HR 3.95, 95% CI 2.72–5.72). The Fagan nomogram revealed the “post-test” probability of tumor recurrence increased by 29% for patients with positive post-BCG FISH test. The baseline FISH test had a pooled sensitivity of 0.70 (95% CI 0.55–0.81), specificity of 0.41 (95% CI: 0.26–0.58), and AUC of 0.60 (95% CI: 0.56–0.64) for predicting recurrence. CONCLUSION: The post-BCG FISH test can predict BCG failure with high specificity and patients with positive post-BCG FISH test were more likely to recur. However, the relatively low sensitivity of post-BCG FISH test and unsatisfactory performance of baseline FISH test may limit their mono-use.