Liquid Biopsy for Cancer Detection in Dogs

Joanne Intile, DVM, MS, DACVIM (Oncology), North Carolina State University

ArticleLast Updated November 20222 min read
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In the literature

Flory A, Kruglyak KM, Tynan JA, et al. Clinical validation of a next-generation sequencing-based multi-cancer early detection “liquid biopsy” blood test in over 1,000 dogs using an independent testing set: the CANcer Detection in Dogs (CANDiD) study. PLoS One. 2022;17(4):e0266623. doi:10.1371/journal.pone.0266623

The Research …

Liquid biopsy methods test for disease markers in blood and are used for early cancer detection in humans. Liquid biopsy can detect cell-free DNA (ie, portions of DNA shed from cells that circulate in the bloodstream).

This study* was designed to validate performance of a novel, commercially available liquid biopsy test for noninvasive detection and characterization of multiple cancers in dogs. An international heterogeneous population of dogs with and without cancer was enrolled. Plasma was collected from dogs that met inclusion criteria, with samples from 876 dogs used to test performance analysis. Cell-free DNA was extracted from plasma samples, and next-generation sequencing was used to compare DNA sequences from patient genomic DNA and cell-free DNA. Bioinformatic algorithms were used to determine whether patient samples showed a positive (ie, cancer signal detected) or negative (ie, cancer signal not detected) result.

Overall sensitivity was 54.7% and specificity was 98.5%. Although sensitivity was low, most dogs with cancer had local or locoregional disease; these patients may have inherently less cell-free DNA than dogs with widespread disease. Sensitivity was 85.4% in patients with cancers (ie, lymphoma, hemangiosarcoma, osteosarcoma) typically associated with systemic involvement at diagnosis.

… The Takeaways

Key pearls to put into practice:

  • Measuring cell-free DNA with a blood test may lead to improved outcomes in cancer patients, especially those with aggressive tumors.

  • Liquid biopsy can be used for cancer screening and may lead to earlier detection of disease and relapse and an improved outcome. In this study, 2 out of 10 presumed healthy dogs were diagnosed with cancer after undergoing a confirmatory cancer evaluation triggered by a positive liquid biopsy result.

  • A positive liquid biopsy result may be challenging to confirm due to limitations in imaging sensitivity and thus may not result in immediate therapeutic action.

*This study received funding from PetDx.