# Plasma circulating tumor DNA in pancreatic cancer patients is a prognostic marker

Source: https://onco.cc/key-papers/paper-pietrasz-ctdna-prognostic-pancreatic-ccr-2017/  
OnCo record `paper-pietrasz-ctdna-prognostic-pancreatic-ccr-2017` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Among 135 patients, those with detectable tumour DNA in blood lived 6.5 months against 19, and the more of it there was the shorter the survival; after surgery, finding it predicted early recurrence.

## Summary

Blood samples were prospectively collected from consecutive pancreatic adenocarcinoma patients treated at one centre from 2011 to 2015, with circulating tumour DNA identified by targeted next-generation sequencing and picolitre droplet digital PCR. Of 135 patients (31 resectable, 36 locally advanced, 68 metastatic), 50 of 104 with advanced disease (48%) had detectable ctDNA at a median mutant allele fraction of 6.1%. Detection correlated strongly with poor overall survival (6.5 versus 19.0 months; multivariate hazard ratio 1.96), and allele-fraction tertiles gave 18.9, 7.8 and 4.9 months. Among 31 patients resected with curative intent, 6 had detectable ctDNA after surgery at a mean allele fraction of 4.4%, with shorter disease-free (4.6 versus 17.6 months) and overall survival (19.3 versus 32.2 months).

## Fields

- Kind: Key paper
- Last checked: 2026-09-24
- Journal: Clinical Cancer Research
- Year: 2017
- DOI: 10.1158/1078-0432.CCR-16-0806
- Authors: Pietrasz D, Pecuchet N, Garlan F, et al.
- Findings: ctDNA detectable in 48% of advanced patients; overall survival 6.5 versus 19.0 months.; Allele-fraction tertiles: 18.9, 7.8 and 4.9 months.; Post-resection ctDNA: disease-free survival 4.6 versus 17.6 months.
- What it means: ctDNA quantity, not just presence, grades prognosis, which is why trials now stratify by allele fraction rather than by a yes or no.
- Caveats: Single centre; assays differed between patients.; Only 31 resected patients.

## Sources

- Pietrasz et al., Clin Cancer Res 2017: plasma ctDNA is prognostic in 135 patients: https://doi.org/10.1158/1078-0432.CCR-16-0806
- PubMed: https://pubmed.ncbi.nlm.nih.gov/27993964/

## Connected records

- biomarkers: [ctDNA MRD positivity (molecular residual disease after curative treatment)](https://onco.cc/biomarkers/ctdna-mrd-positive/)
- cancers: [Metastatic pancreatic ductal adenocarcinoma](https://onco.cc/cancers/metastatic-pdac/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/), [Resectable pancreatic ductal adenocarcinoma](https://onco.cc/cancers/resectable-pdac/)
- technologies: [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/)
- terms: [Cell-free DNA (cfDNA)](https://onco.cc/terms/cfdna/), [Circulating tumour DNA (ctDNA)](https://onco.cc/terms/ctdna/), [Minimal / molecular residual disease (MRD)](https://onco.cc/terms/mrd/)
- journals: [Clinical Cancer Research](https://onco.cc/journals/clinical-cancer-research/)

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