# ctDNA MRD positivity (molecular residual disease after curative treatment)

Source: https://onco.cc/biomarkers/ctdna-mrd-positive/  
OnCo record `ctdna-mrd-positive` (Biomarker). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A ctDNA MRD test looks for the tumour's own mutations in blood after surgery. Detection predicts relapse months before scans, and in 2026 the FDA approved Signatera as the companion test selecting bladder cancer patients for adjuvant atezolizumab.

## Summary

Tumour-informed assays (Signatera, RaDaR, NeXT Personal) sequence the tumour first and track a personalised set of variants in plasma; tumour-naive assays (Guardant Reveal) use mutations and methylation without a tumour sample. A positive result is any detection above the assay's calling threshold, reported as detected or not detected with a level. IMvigor011 showed a survival benefit for atezolizumab over placebo in ctDNA-positive muscle-invasive bladder cancer after cystectomy, and the FDA list carries Signatera CDx as the companion diagnostic for Tecentriq in that setting (P260004, 15 May 2026); the Tecentriq label read on 20 May 2026 predates the indication text in the openFDA copy, so the threshold here is quoted from the FDA list. In colorectal cancer the DYNAMIC trial and the ongoing CIRCULATE trials use ctDNA to guide adjuvant chemotherapy. As a genome-wide readout it sits under no target.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: ctDNA MRD; ctDNA positive; ctDNA-positive; molecular residual disease; MRD-positive ctDNA; Signatera positive; ctDNA detected after surgery
- Tags: biomarker; genome-wide; ctdna

## Sources

- FDA: List of FDA-Authorized Companion Diagnostic Devices: https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools
- TECENTRIQ prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6fa682c9-a312-4932-9831-f286908660ee

## Connected records

- biomarkers: [ESR1 mutation (ligand-binding domain, usually in ctDNA)](https://onco.cc/biomarkers/esr1-mutation-ctdna/), [TMB-high (tumour mutational burden >= 10 mutations per megabase)](https://onco.cc/biomarkers/tmb-high/)
- cancers: [Bladder & urothelial cancer](https://onco.cc/cancers/urothelial/), [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- drugs: [Atezolizumab](https://onco.cc/drugs/atezolizumab/), [clonoSEQ](https://onco.cc/drugs/clonoseq/), [Guardant Reveal](https://onco.cc/drugs/guardant-reveal/), [Oncodetect](https://onco.cc/drugs/oncodetect/), [RaDaR](https://onco.cc/drugs/radar-mrd/), [Signatera](https://onco.cc/drugs/signatera/)
- 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/), [Tumour-informed versus tumour-naive ctDNA assays](https://onco.cc/terms/tumour-informed-assay/)

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