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Circulating tumour DNA (ctDNA) consists of fragments of DNA shed by tumour cells into the blood, detectable with sensitive sequencing.
Circulating tumour DNA (ctDNA) is made up of DNA fragments shed by tumour cells into the bloodstream, where they form only a small fraction of all cell-free DNA and are detected with sensitive sequencing. Its uses span genotyping for companion diagnostics, tracking resistance mutations such as EGFR T790M and ESR1, molecular residual disease, early detection and response monitoring. Shedding varies with tumour type and burden, and clonal haematopoiesis can confound results. The term underpins the Liquid biopsy (ctDNA), MRD / molecular residual disease testing and Multi-cancer early detection (MCED) technologies, and it appears in the SERENA-6, CIRCULATE-Japan and IMvigor011 trials and in ideas on molecular-progression switching beyond ESR1 and HPV ctDNA to guide cervical cancer therapy.
Showing the technology this term belongs to: Liquid biopsy (ctDNA).
The glossary entry explains the word; the readout page carries the scoring rule, the thresholds approvals use, the companion diagnostics and the tests.
The 48 most recent of 57 papers; see them all →
Residual-disease testing may not need the tumour to be sequenced first, which would remove the slowest step of tumour-informed assays; the comparison with tumour-informed results in the same patients is the evidence that matters.
Together with the JCO Precision Oncology cohort this makes residual disease testing in biliary cancer prognostic to the same degree as in colon cancer. Nobody has yet shown that acting on it helps; that is the trial gap the ideas on this page name.
Very wide confidence intervals from a small cohort, but the direction matches the larger 2026 analysis. Gallbladder cancer recurs early and distantly after re-resection, which is exactly the setting where a residual disease test could pick who gets more than capecitabine.
HER2 is as frequent in India as in the West, so HER2 testing pays off in the highest-incidence population, while tumour-agnostic immunotherapy markers will rarely apply. The paper also shows plasma testing is feasible where tissue is scarce.
After bladder removal, a blood test can now tell who needs immunotherapy and who can safely be spared it. This is the model for MRD-guided adjuvant therapy across cancers: treat the blood-positive, watch the blood-negative.
Patients newly diagnosed with EGFR-mutated advanced lung cancer now have a first-line option that improves survival over osimertinib, particularly if they have high-risk features. The trade-off is intravenous (now subcutaneous) infusions and considerably more skin, nail and clotting toxicity, so osimertinib alone remains reasonable for those who prioritise convenience and tolerability. Both this regimen and osimertinib plus chemotherapy (FLAURA2) are approved; there is no direct comparison.
ctDNA and RCB measure different things and both should stratify post-neoadjuvant TNBC trials; an RCB-II patient with negative ctDNA has an 87% three-year event-free survival.
The blood test stratifies risk far better than stage or pathology. It supports treating ctDNA-positive patients and suggests ctDNA-negative patients gain little from chemotherapy, but because treatment was not randomised the de-escalation claim needs the randomised trials that are now under way.
Shares ESMO recommendations on the use of circulating tumour DNA assays for patients with cancer: a report from the ESMO Precision Medicine Working Group, Tracking early lung cancer metastatic dissemination in TRACERx using ctDNA, c-TRAK TN analysis: tissue-free versus tumour-informed ctDNA assays for residual disease in early triple-negative breast cancer, ctDNA and residual cancer burden are prognostic in triple-negative breast cancer patients with residual disease and the tag precision.
Shares Fund a biopsy at progression, every time, as standard care, Drop mandatory fresh biopsies where blood or archival tissue would do, Acquired EGFR C797S mutation mediates resistance to AZD9291 in non-small cell lung cancer harboring EGFR T790M, I-PREDICT and the tag precision.
Shares KIT exon 11-mutant GIST, Recurrent and metastatic nasopharyngeal carcinoma, Gastrointestinal stromal tumour (GIST), Borderline resectable pancreatic ductal adenocarcinoma and the tag precision.
Shares A test to tell true oligometastatic disease from hidden widespread spread, The metastatic cascade, Recurrent and metastatic nasopharyngeal carcinoma, Precision roadmap: margins measured in millimetres → tests that find a target → doses fitted to the person → precision that changes outcomes and the tag precision.
Shares DNA, Biomarker, Biopsy, Liquid biopsy (ctDNA) and the tag precision.
Shares National Cancer Center Hospital East, Recurrent and metastatic nasopharyngeal carcinoma, Precision roadmap: margins measured in millimetres → tests that find a target → doses fitted to the person → precision that changes outcomes, University College London Hospitals / UCL Cancer Institute and the tag precision.
Shares Blood-based tumor mutational burden as a predictor of clinical benefit in non-small-cell lung cancer patients treated with atezolizumab, Triple-negative breast cancer (TNBC), Pancreatic ductal adenocarcinoma, Colorectal cancer and the tag precision.
Shares Stage IIB and IIC melanoma, Precision roadmap: margins measured in millimetres → tests that find a target → doses fitted to the person → precision that changes outcomes, Metastasis is understood least and studied last, Triple-negative breast cancer (TNBC) and the tag precision.