Key Clinical Takeaways: 

• Design/Population: This retrospective study evaluated plasma ctDNA in 42 patients with muscle-invasive bladder cancer treated with trimodality therapy. Patients were stratified by post-treatment ctDNA status and assessed for metastasis-free and recurrence-free survival. 
• Key Outcomes: ctDNA positivity accurately identified all metastatic recurrences, with 100% sensitivity and 95% specificity at 1 year, and preceded clinical detection by a median of 57 days. ctDNA-positive status was strongly associated with inferior metastasis-free and recurrence-free survival.
• Clinical Relevance: Plasma ctDNA may serve as a valuable surveillance biomarker for early detection of metastatic progression after bladder-sparing therapy. These findings support further prospective studies to evaluate ctDNA-guided monitoring strategies following trimodality therapy.

According to results from a retrospective analysis, plasma circulating tumor DNA (ctDNA) demonstrated strong potential as a biomarker for early detection of metastatic recurrence in patients with muscle-invasive bladder cancer treated with trimodality therapy.

These results were presented by Dekuang Zhao, DO, PhD, University of South Florida, Tampa, Florida, at the 2026 ACRO Radiation Oncology Summit in Orlando, Florida. 

In this study, investigators collected data from 42 patients who underwent trimodality therapy. Patients were stratified based on post-treatment ctDNA status as either ctDNA-positive (n = 6) or ctDNA-negative (n = 36) and assessed for metastasis-free survival and recurrence-free survival using Kaplan-Meier estimates and Cox regression models.

At a median follow-up of 14.7 months, 83% of ctDNA-positive patients developed radiographic evidence of metastatic disease, whereas none of the ctDNA-negative patients experienced metastatic progression. ctDNA positivity identified all cases of metastatic progression with a sensitivity of 100% and a specificity of 95% at 1-year surveillance.

Detection of ctDNA preceded clinical or radiographic identification of metastasis by a median of 57 days, with a maximum lead time of 139 days. ctDNA-positive status was significantly associated with worse metastasis-free survival (P <.0001) and recurrence-free survival (P = .0005). In univariable analysis, ctDNA positivity was the only variable significantly associated with inferior recurrence-free survival (hazard ratio [HR], 6.36; 95% confidence interval [CI], 1.93 to 20.96; P = .0024).

“Our hypothesis-generating findings provide a basis for larger studies to evaluate the utility of ctDNA-guided surveillance post-[trimodality therapy],” concluded Dr Zhao et al. 

Source: 

Zhao, D. Early detection of metastatic progression by circulating tumor DNA in patients undergoing bladder-preserving trimodality therapy. Presented at the 2026 ACRO Radiation Oncology Summit. February 4 - 7, 2026. Orlando, Florida. Abstract 1598