# A clone report from blood at every treatment cycle

Source: https://onco.cc/ideas/idea-bio1-ctdna-clone-report/  
OnCo record `idea-bio1-ctdna-clone-report` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Blood tests can already detect tumour DNA. Reporting which sub-populations of the tumour are growing or shrinking, cycle by cycle, would turn the test into an evolution monitor.

## Summary

Phylogenetic ctDNA analysis, as developed in TRACERx, assigns plasma variants to tumour subclones and tracks their relative abundance. The proposal is a standardised clinical report in which each ctDNA draw lists clone fractions, emergent clones, and clone-specific drug sensitivities, rather than a flat list of variants and allele frequencies.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: Clone-level ctDNA reporting detects the expansion of a resistant subclone a median of three or more months before radiographic progression and changes management in at least a fifth of patients on targeted therapy.
- Rationale: Resistance is subclone expansion. Existing panels report VAFs without the phylogenetic context that distinguishes clonal shrinkage from branch escape. The maths exists; the reporting format does not.
- Proposed test: Retrospective analysis on serial plasma from a completed TKI trial to compute lead time; then a prospective single-arm study in EGFR or ALK lung cancer where clinicians receive clone reports and act on pre-specified rules.
- Maturity: early-clinical
- Actor: data

## Sources

- Bottleneck evidence (Tumour heterogeneity and clonal evolution): Gerlinger et al., Intratumor heterogeneity and branched evolution (NEJM 2012): https://doi.org/10.1056/NEJMoa1113205

## Connected records

- ideas: [Molecular-progression switching beyond ESR1](https://onco.cc/ideas/idea-ctdna-switch-generalised/)
- cancers: [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/)
- technologies: [Liquid biopsy (ctDNA)](https://onco.cc/technologies/liquid-biopsy/), [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/)
- drugs: [Osimertinib](https://onco.cc/drugs/osimertinib/)
- terms: [Circulating tumour DNA (ctDNA)](https://onco.cc/terms/ctdna/), [Variant allele frequency (VAF)](https://onco.cc/terms/vaf/)
- bottlenecks: [Acquired resistance to every therapy](https://onco.cc/bottlenecks/b-resistance/), [Tumour heterogeneity and clonal evolution](https://onco.cc/bottlenecks/b-tumor-heterogeneity/)
- key papers: [Gerlinger: a single biopsy misses most of the mutations in a kidney tumour](https://onco.cc/key-papers/paper-gerlinger-intratumour-heterogeneity-nejm-2012/)

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