Circulating Tumour DNA Is a Strong Predictor of Outcomes in Patients Treated with Systemic Therapy for Urothelial Carcinoma

We summarise the available data for and assess the prognostic value of circulating tumour DNA (ctDNA) in patients treated with systemic therapy for urothelial carcinoma (UC). Studies were deemed eligible if they reported on oncologic outcomes for patients with UC treated with systemic therapy according to the baseline ctDNA profile (before starting systemic therapy) and/or changes over the course of therapy. Five studies met the eligibility criteria. We found a strong association between high baseline ctDNA levels and worse disease-free survival (DFS; hazard ratio [HR] 3.53, 95% confidence interval [CI] 2.58-4.84) and overall survival (OS; HR 2.99, 95% CI 2.17-4.13). Patients with a decline in ctDNA level after immunotherapy had better DFS (HR 0.25, 95% CI 0.13-0.49) and OS (HR 0.10, 95% CI 0.03-0.42) in comparison to patients without a ctDNA decline. Conversely, an increase in ctDNA levels after immunotherapy was associated with worse survival outcomes. Patients with UC who exhibited a decrease in ctDNA levels during systemic therapy had better survival outcomes compared to those with stable or increasing ctDNA levels. PATIENT SUMMARY: Measurement of tumour DNA in blood may help in identifying patients with cancer of the urinary tract who are unlikely to respond to chemotherapy or immunotherapy. This could serve as a biomarker for monitoring cancer treatment.