Post-surgical ctDNA-based molecular residual disease detection in patients with stage I uterine malignancies.

INTRODUCTION: Among uterine malignancies, endometrial cancer (EC) is the most common cancer of the female reproductive tract. Traditionally, risk stratification in EC is determined by standard clinicopathological risk factors. Although circulating tumor DNA (ctDNA) has emerged as a prognostic biomarker in various malignancies, its clinical validity in EC remains to be established. METHODS: In this analysis of real-world data, 267 plasma samples from 101 patients with stage I EC were analyzed using a tumor-informed ctDNA assay (Signatera™ bespoke mPCR-NGS). Patients were followed post-surgically and monitored with ctDNA testing for a median of 6.8 months (range: 0.37-19.1). RESULTS: Patients who tested ctDNA-positive at both their first time point and longitudinally experienced inferior recurrence-free survival (RFS) (HR = 6.2; p = 0.0006 and HR = 15.5; p < 0.0001, respectively), and showed a recurrence rate of 58% and 52%, vs. 6% and 0%, respectively for the ctDNA-negative patients. Most ctDNA-positive patients had high-risk histologies or sarcoma, versus low-risk and high-intermediate risk (H-IR) EC. Furthermore, patients with high-risk histologies who were ctDNA-positive showed shorter RFS compared to those who tested negative (HR = 9.5; p = 0.007), and those who tested positive in the low/H-IR cohort (HR = 0.25; p = 0.04). Post-surgically, detectable ctDNA was highly prognostic of clinical outcome and remained the only significant risk factor for recurrence when adjusted for clinicopathological risk factors, such as histologic risk group, mismatch repair (MMR), and p53 status. CONCLUSION: Incorporating ctDNA monitoring along with traditional known risk factors may aid in identifying patients with stage I EC who are at highest risk of recurrence, and possibly aid in treatment stratification.

Association of Tumor-informed Circulating Tumor DNA Detectability Before and After Radical Cystectomy with Disease-free Survival in Patients with Bladder Cancer.

BACKGROUND AND OBJECTIVE: Despite curative-intent radical cystectomy (RC), patients with muscle-invasive bladder cancer (MIBC) are at high risk of recurrence. Biomarkers are urgently needed to refine prognostication and selection of appropriate perioperative systemic therapies. Our aim was to evaluate the prognostic and predictive value of tumor-informed circulating tumor DNA (ctDNA) results in a multicenter cohort of patients with bladder cancer who underwent RC. METHODS: We performed a retrospective analysis of real-world data for a commercial ctDNA test (Signatera; Natera, Austin, TX, USA) performed in 167 patients (852 plasma samples) before RC and during molecular residual disease (MRD; adjuvant decision) and surveillance windows. We assessed the correlation between recurrence and ctDNA status before and after RC using Cox regression analysis. RESULTS AND LIMITATIONS: During study-defined postoperative MRD and surveillance windows, detectable ctDNA was associated with shorter disease-free survival (DFS) when compared to undetectable ctDNA (MRD: hazard ratio 6.93; p < 0.001; surveillance: hazard ratio 23.02; p < 0.001). Of note, patients with undetectable ctDNA did not appear to benefit from adjuvant therapy (p = 0.34). Detectable ctDNA in the pre-RC (p = 0.045), MRD (p = 0.002), and surveillance (p < 0.001) windows was the only risk factor independently associated with shorter DFS. Limitations include the retrospective and nonrandomized nature of the study. CONCLUSIONS: ctDNA testing in patients with bladder cancer undergoing RC was prognostic and potentially predictive. Identification of patients at high risk of recurrence may aid in patient counseling and decision-making. PATIENT SUMMARY: We found that outcomes for patients with muscle-invasive bladder cancer are strongly linked to detection of tumor DNA in blood samples. The results show the value of tumor-informed testing for tumor DNA in blood for decisions on the best treatment for each individual patient.