Seeing Below the Limit of Detection: A Censored-Poisson Bayesian Latent-Growth Change-Point Detector (the Span Detector) for Serial ctDNA in HR+/HER2- Metastatic Breast Cancer
arXiv:2606.11876v1 Announce Type: cross Abstract: Circulating-tumour DNA (ctDNA) carries evidence of drug resistance months before imaging shows it, but the earliest evidence lives below the assay's limit of detection (LoD): a nascent subclone is detected only intermittently, producing a flickering sequence of faint detects and non-detects. Commercial liquid biopsies treat each draw as an independent snapshot and a non-detect as nothing. We argue a non-detect is a left-censored observation, and the pattern of non-detects and faint detects over time carries actionable evidence of growth before
The convergence of advanced computational methods, Bayesian statistics, and increasing data availability from liquid biopsies enables new techniques for early disease detection.
This development allows for earlier and more nuanced detection of cancer recurrence and treatment resistance, offering a significant advantage in patient outcomes and drug development strategies.
Traditional diagnostic limitations of 'limit of detection' for biomarkers are being overcome, transforming how early-stage disease progression is monitored and intervention timelines are determined.
- · Oncology patients
- · Precision medicine companies
- · Biopharmaceutical companies (early intervention)
- · AI/ML in health tech
- · Traditional diagnostic imaging (recedes in importance for early detection)
- · Late-stage oncology treatment developers (as earlier detection becomes standard)
Earlier detection of drug resistance in cancer leads to more timely treatment adjustments and improved patient survival rates.
This methodology could reduce overall healthcare costs by preventing progression to more expensive, late-stage disease.
It may enable a shift towards a 'pre-emptive' oncology model, where treatments are initiated based on molecular signals rather than symptomatic presentation or imaging.
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Read at arXiv cs.LG