Circulating tumor DNA as a Predictive and Prognostic Biomarker in the Perioperative Treatment of Muscle-invasive Bladder Cancer: A Systematic Review

CONTEXT: Predictive and prognostic biomarkers in the perioperative treatment of muscle-invasive bladder cancer (MIBC) are an unmet need. Circulating tumor DNA (ctDNA) holds promise as a biomarker in this setting. OBJECTIVE: To review the evidence of ctDNA as a prognostic and predictive biomarker in the perioperative treatment of MIBC. EVIDENCE ACQUISITION: We systematically reviewed the literature using PubMed, MEDLINE, and Embase databases according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. We included prospective studies investigating neoadjuvant and/or adjuvant chemotherapy and/or immunotherapy for MIBC (T2-T4a, any N, and M0) treated with radical cystectomy. We reported ctDNA results to monitor and/or predict disease status, relapse, and progression. The research retrieved 223 records. Six papers were considered for this review based on prespecified inclusion criteria. EVIDENCE SYNTHESIS: Our review confirms the prognostic role of ctDNA after cystectomy and shows a potential predictive benefit in using neoadjuvant chemotherapy and preoperative immunotherapy. Circulating tumor DNA was used to monitor recurrence, and changes in ctDNA status anticipated radiological progression with a median difference of time from 101 to 932 d. A subgroup analysis of the phase 3 Imvigor010 trial showed that only ctDNA-positive patients treated with atezolizumab had an improvement in disease-free survival (DFS; hazard ratio [HR] = 3.36, 95% confidence interval [CI]: 2.44-4.62). Clearance of ctDNA after two cycles of adjuvant atezolizumab was associated with improved outcomes (DFS HR = 0.26, 95% CI: 0.12-0.56, p = 0.0014; overall survival HR = 0.14, 95% CI: 0.03-0.59). CONCLUSIONS: Circulating tumor DNA is a prognostic factor after cystectomy and may be used to monitor recurrence. In the adjuvant immunotherapy setting, ctDNA might select patients who benefit the most from this strategy. PATIENT SUMMARY: In the perioperative treatment of muscle-invasive bladder cancer, circulating tumor DNA (ctDNA) positivity correlates with the outcomes after cystectomy and might select patients who may benefit from neoadjuvant chemotherapy and/or immunotherapy. Changes in ctDNA status anticipated radiological progression.