Pilot study tests liquid biopsy for lymphoma monitoring in dogs

Version 2

A small pilot evaluation is pointing to a possible new role for liquid biopsy in canine lymphoma care: monitoring dogs over time while they’re on treatment. The study assessed IDEXX Cancer Dx in 10 dogs with multicentric lymphoma undergoing a 25-week CHOP chemotherapy protocol and found that test results generally tracked with clinical response, turning negative during remission in dogs that had initially tested positive. Still, the investigators and IDEXX both stop well short of positioning the assay as a replacement for conventional monitoring, emphasizing that larger studies are needed before it could be used as a reliable stand-alone tool. (idexx.com)

That matters because IDEXX launched Cancer Dx for canine lymphoma in January 2025 as a blood-based test aimed at earlier detection and diagnostic support, not as a validated monitoring platform. The company said at launch that the assay was designed to fit routine veterinary workflows and provide qualitative lymphoma results, with B-cell and T-cell phenotype classification when available. In other words, this pilot sits within a broader push to make liquid biopsy part of everyday canine oncology workups, while the evidence base is still expanding from screening and aid-in-diagnosis into treatment monitoring and recurrence surveillance. (ir.idexx.com)

The pilot itself was prospective but small. Twelve client-owned dogs with suspected multicentric lymphoma were enrolled, and 10 met inclusion criteria for analysis. Eligible dogs had treatment-naive lymphoma, confirmed by cytology or histology reviewed by a boarded pathologist, plus phenotype or genotype determination by flow cytometry or PARR, and all were treated with CHOP. According to the study summary, all 10 analyzed dogs had positive Cancer Dx results at the initial visit, all achieved complete remission, and all became negative during treatment according to the assay. Three dogs progressed during the protocol, and two of those three had positive Cancer Dx results at the time of progression. At an interim follow-up reported in August 2025, seven of 10 dogs remained in complete remission, with one of those seven showing a positive Cancer Dx result, while both dogs that had relapsed or progressed were positive on the test. (idexx.com)

Those findings line up with the study abstract’s main takeaway: good concordance with clinical response criteria, but not enough performance to support the test as a sole monitoring method. That nuance is important. A blood-based assay that trends with remission status could be clinically useful as an adjunct, especially when serial lymph node measurements, cytology, imaging, and client logistics don’t provide a clean picture. But the fact that not every progression event was captured, and that at least one dog in clinical remission remained test-positive at follow-up, underscores the unresolved question of how molecular signals should be interpreted in real time. It’s possible, though not yet proven here, that some discordant results could reflect minimal residual disease or impending relapse rather than simple test error. (idexx.com)

Outside this pilot, the broader field has been moving in the same direction. A 2023 study of next-generation sequencing-based liquid biopsy in dogs reported potential utility for detecting residual disease and monitoring recurrence, including longitudinal follow-up samples in some patients. Earlier validation work in the CANDiD study established that liquid biopsy can detect several canine cancers, including lymphoma, but explicitly noted that post-diagnosis longitudinal uses such as minimal residual disease detection and recurrence monitoring had not yet been determined. Reviews from academic and professional sources have similarly described liquid biopsy as promising for monitoring treatment efficacy and recurrence, while stressing that evidence is still developing. (pubmed.ncbi.nlm.nih.gov)

Industry and clinical commentary has largely focused on screening and early detection so far, but it helps frame where monitoring could fit. In a dvm360 interview published in January 2026, oncologist Pamela D. Jones said Cancer Dx is a true liquid biopsy blood test and argued that its best current use is targeted screening in older or at-risk dogs, where pretest probability is higher and false positives are less disruptive. That’s a useful reminder for clinicians: enthusiasm around liquid biopsy is real, but practical adoption still depends on matching the test to the right use case and understanding where evidence is strongest today. (dvm360.com)

Why it matters: For veterinary professionals, this pilot is less about changing protocol tomorrow and more about where oncology diagnostics may be heading. If future studies show that serial liquid biopsy can reliably identify remission, residual disease, or relapse earlier than physical exam and conventional follow-up, it could become a valuable adjunct in lymphoma case management and client communication. It may be especially attractive in general practice and shared-care settings, where a simple blood draw is easier to repeat than more invasive or specialist-dependent assessments. For now, though, the evidence supports cautious interest, not substitution: clinicians should view this as an emerging add-on to established monitoring tools, rather than a replacement for them. (idexx.com)

What to watch: The next key milestones are larger prospective validation studies, peer-reviewed publication beyond conference or company materials, and clearer evidence on whether a positive liquid biopsy during apparent remission predicts clinical relapse early enough to change management. IDEXX has also signaled broader ambitions for Cancer Dx beyond lymphoma, so veterinary teams should expect more data on where the platform fits across screening, diagnosis, and longitudinal cancer care. (idexx.com)