A new single-centre study has demonstrated a significant link between circulating tumour DNA (ctDNA) and tumour volume in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). The findings strengthen ctDNA’s role as a non-invasive biomarker that could refine prognosis and guide treatment in advanced pancreatic cancer
Understanding ctDNA as a Prognostic Marker
ctDNA, fragments of tumour-derived DNA circulating in the bloodstream, has become an important focus for cancer detection and monitoring. Despite its promise, about one-third of patients with mPDAC have no detectable ctDNA. Researchers at a French oncology centre sought to understand whether tumour size and burden influence ctDNA levels, particularly looking at both total and liver tumour volumes.
Study Findings
In a cohort of 71 chemotherapy-naïve patients with mPDAC, ctDNA quantity was measured at baseline using droplet digital PCR targeting two methylated genes, HOXD8 and POU4F1. Tumour volumes were calculated in three dimensions from CT scans of both primary and metastatic lesions. ctDNA was found in 66.2% of patients, showing a moderate but statistically significant correlation with both total and liver tumour volumes. The correlation coefficients were 0.353 (p = 0.01) for total tumour volume and 0.500 (p < 0.001) for liver tumour volume. On average, patients with detectable ctDNA had considerably higher total and liver tumour volumes—129.5 mL versus 31.8 mL and 18 mL versus 1 mL, respectively. Detection thresholds of 90.1 mL for total tumour volume and 3.7 mL for liver metastases were identified.
Implications for Pancreatic Cancer Management
The study highlights that ctDNA is more likely to be detected in patients with larger tumour burdens, especially when liver metastases are present. This moderate correlation underscores ctDNA’s potential as a complementary biomarker alongside imaging in metastatic pancreatic cancer, improving patient monitoring and informing treatment decisions. Integrating ctDNA analysis with volumetric imaging could enhance disease assessment and enable more personalised therapeutic strategies.
Reference
Caliez O et al. Correlation between circulating tumor DNA quantity assessed by methylated markers and tumor volume in patients with metastatic pancreatic adenocarcinoma. Scientific Reports. 2025;15:34865.
