1. Identify patient-specific variants
Whole-exome sequencing of tumour tissue and a matched-normal blood sample identifies patient-specific somatic variants.
Tumour-informed ctDNA monitoring
Personalised molecular monitoring across the cancer care continuum
Signatera™ is a personalised, tumour-informed circulating tumour DNA (ctDNA) assay designed to support molecular residual disease assessment, recurrence monitoring and treatment response monitoring. By tracking patient-specific tumour variants in blood over time, Signatera provides molecular insights that can complement clinical, imaging and pathological assessment across selected tumour types and treatment settings.
When to consider Signatera™
Signatera can support molecular disease monitoring at different points across the cancer care continuum, from treatment response assessment to post-treatment surveillance. Its use should be considered according to tumour type, stage, treatment setting and the available clinical evidence.
Assess molecular response before surgery or further treatment decisions, where clinically appropriate.
Identify patients with MRD and support recurrence-risk assessment after curative-intent surgery.
Monitor for molecular recurrence during follow-up, alongside imaging, tumour markers and clinical assessment.
Track ctDNA kinetics over time to support assessment of response or progression during systemic treatment.
The role of ctDNA
Why ctDNA matters in molecular residual disease
Circulating tumour DNA (ctDNA) is shed by tumour cells into the bloodstream and can be used as a blood-based biomarker to monitor disease status over time. After curative-intent treatment, ctDNA detection may indicate molecular residual disease before clinical or radiological recurrence, helping support recurrence-risk assessment, treatment response assessment and recurrence monitoring.
Blood-based: enables minimally invasive molecular monitoring over time.
Tumour-informed: reflects molecular information originating from the tumour.
Longitudinal: repeated measurements can provide insight into changes in molecular disease status.
How Signatera works
Personalised, tumour-informed ctDNA monitoring
Signatera is individually designed from each patient’s tumour profile. By identifying patient-specific somatic variants and tracking them in plasma over time, the assay enables longitudinal monitoring of tumour-derived ctDNA.
2. Build a personalised assay
A personalised multiplex PCR assay, followed by NGS, is designed to track 16 selected clonal tumour variants in plasma.
3. Monitor ctDNA over time
Serial blood samples are used to monitor tumour-derived ctDNA longitudinally.
Designed for highly sensitive, specific ctDNA monitoring
Signatera is designed to detect very low levels of ctDNA in blood and determine the presence or absence of molecular residual disease under assay conditions. By tracking patient-specific tumour variants, the assay supports highly sensitive and specific longitudinal monitoring.
Interpreting results
Understanding ctDNA changes over time
Results should be interpreted alongside clinicopathological and imaging findings. A not-detected result does not exclude ctDNA below the assay’s detection limit.
Detected → decreasing / not detected
A decline in ctDNA may be consistent with molecular response.
Detected → increasing
Rising ctDNA may indicate persistent or progressive molecular disease and should prompt further clinical assessment.
Not detected → not detected
No ctDNA is detected under assay conditions; continued monitoring may still be appropriate depending on the clinical setting.
Not detected → detected
Newly detected ctDNA may indicate molecular recurrence and should be interpreted in conjunction with imaging and clinical assessment.
Evidence across tumour types
Published studies support tumour-informed ctDNA monitoring across multiple tumour types and treatment settings. Evidence demonstrates its potential to support recurrence-risk assessment, post-treatment surveillance and, in selected settings, treatment decisions. Clinical utility varies by tumour type, disease stage and available evidence.
In MIBC, ctDNA has demonstrated both prognostic and predictive value following cystectomy. The phase III IMvigor011 trial showed that Signatera-guided adjuvant atezolizumab significantly improved disease-free and overall survival in ctDNA-positive patients (overall survival HR 0.59).
Additional evidence from IMvigor010 and longitudinal monitoring studies has shown that post-cystectomy ctDNA status is strongly associated with recurrence risk. Molecular recurrence was detected up to 245 days before clinical recurrence (median 96 days) in a longitudinal study.
In resectable colorectal cancer, post-surgical ctDNA status is a strong prognostic marker for recurrence risk and survival. Data from the large prospective GALAXY study showed that ctDNA-positive patients had substantially poorer outcomes, with 36-month overall survival of approximately 72% compared with 96% in ctDNA-negative patients.
Longitudinal ctDNA monitoring may provide additional information on molecular recurrence and treatment response, complementing conventional follow-up and clinical assessment.
In breast cancer, emerging clinical evidence supports the prognostic value of ctDNA for identifying patients at increased risk of recurrence. In a longitudinal study, ctDNA-positive patients were 52 times more likely to experience relapse, with molecular recurrence detected a median of 10.5 months before clinical detection.
Ongoing interventional studies, including DARE, are investigating whether ctDNA-guided surveillance and treatment escalation can improve patient outcomes.
Emerging research suggests that ctDNA monitoring may provide prognostic information in DLBCL, including assessment of molecular response and identification of patients at increased risk of relapse. Its clinical utility and role in treatment decision-making continue to be investigated.
Evidence is also emerging across additional tumour types, including lung cancer and melanoma. Clinical utility should be considered according to tumour type, stage, treatment setting and available data.
Signatera testing requirements
Initial test
Samples / equipment
2 × Streck Cell-Free DNA tubes (10 mL) + 1 × EDTA blood tube (6 mL) + FFPE tumour tissue.
Purpose
Identifies patient-specific tumour variants and establishes the personalised Signatera assay for longitudinal ctDNA monitoring.
Turnaround time
Approximately 4–6 weeks from receipt of the required blood and tissue samples at the Natera laboratory, provided no additional material is required.
Important to know
Obtaining the biopsy or tumour tissue may add additional time. Where appropriate, the referring physician can contact the pathology laboratory in advance to help minimise delays.
Ordering
How to order Signatera™
Signatera kits can be requested directly from the Unilabs Genetics team. For questions about patient eligibility, testing logistics or sample requirements, the team can also provide support.
Kit orders
secretariat.genetics@unilabs.com
+41 21 321 40 51
Turnaround time
Initial test: 4–6 weeks
Follow-up test: 2 weeks
Billing information
Initial test: TARDOC JM.35.0160 — Next Generation Sequencing, big panel
Follow-up test: TARDOC JM.35.0150 — Next Generation Sequencing, middle panel
*Reimbursed according to TARDOC. Prices may vary slightly by canton due to TARDOC point conversion.
Resources for prescribers
Access practical information on Signatera™ testing, ordering procedures and blood sample collection. Technical requirements for tumour tissue samples are managed by Unilabs.
Current Unilabs information on initial and follow-up testing, turnaround times, kit ordering, reimbursement and indications.
Instructions for requisition, blood collection, pre-packing and shipping to Unilabs Genetics in Lausanne.