Tumor characteristics associated with detectable circulating tumor DNA preoperatively in patients with renal masses suspicious for RCC.

Abstract

461 Background: Understanding the specific tumor characteristics associated with detectable ctDNA in the blood of patients with renal cell carcinoma (RCC) is critical to informing future studies seeking to establish the clinical utility of such testing. We characterized pathological and clinical characteristics associated with ctDNA detected preoperatively in patients with renal masses suspicious of RCC. Methods: Using our single institution prospectively maintained database, we identified consecutive patients who underwent partial or radical nephrectomy for non-metastatic suspected RCC (stages cT1b-cT3) during 2022-2023. Included were patients who had undergone tumor-informed ctDNA testing using the commercial Signatera assay (Natera). Baseline characteristics, pathology results, imaging study results, and oncological treatment and follow-up data were collected from the electronic medical records. ctDNA results were collected through the Natera portal. Study findings were reported using descriptive statistics. A p-value of <0.05 was considered statistically significant. R programming language version 4.3 was used for all statistical analyses. Results: A total of 54 patients with a median age of 63 years (IQR 51-71) were included in the study. Twenty-one (39%) were women. The median follow-up time was 4 months (range: 1-21 months). Among the 54 patients, 27 (50%) had detectable ctDNA pre-operatively Post-operative results were available for 33 patients, and 3 (9%) had detectable tDNA (of those 2 had Inferior vena cava involvement). The first patient developed metastatic disease. The two other patients are receiving adjuvant immunotherapy. Analysis of 50 patients with solely malignant RCC revealed that patients with detectable versus undetectable ctDNA were older 67 vs. 54 years (p=0.03), had a higher pathological stage (p= 0.002), larger tumors (7.2 vs. 4.7 cm, p = 0.004), and higher pathological grade (grade 3-4 vs. grade 1-2; p=0.035) (Table 1). All the patients with renal vein or inferior vena cava involvement had detectable ctDNA (n=8). Conclusions: In our cohort, preoperative ctDNA was detectable in 50% of patients with suspected clinically localized RCC. Detectable ctDNA preoperatively correlated with clinically relevant features. The ability of preoperative ctDNA to predict recurrence and survival in patients with clinically localized RCC warrants further evaluation. [Table: see text]