Introduction

Cancer in dogs may occur in anatomical locations that are difficult or impossible to access by fine needle aspiration or surgical biopsy, making confirmation of malignancy difficult, or in some cases, impossible. These “difficult to diagnose” (DTD) cases may include: endocrine, bone, central nervous system (CNS), intra-thoracic, intra-abdominal, upper respiratory tract, and thymic tumors. In such cases, a noninvasive ‘aid in diagnosis’ test may prove valuable in establishing whether the mass is malignant.

Methods

Blood samples from 191 dogs with a variety of cancer diagnoses were subjected to DNA extraction, proprietary library preparation, and next-generation sequencing. Sequencing data were analyzed using an internally developed bioinformatics pipeline to detect genomic alterations associated with the presence of cancer. The testing laboratory was blinded to the cancer status and type of cancer present in these patients until after test results were issued.

Results

In an all-comers cohort of 191 cancer-diagnosed subjects, 33% (n=63) were designated as DTD cases, comprising over 20 distinct cancer types from the above-mentioned classes. In these DTD cases, the noninvasive test yielded a Cancer Signal Detected result in 25 cases, for an overall detection rate of 40%.

Conclusion

A noninvasive, blood-based cancer detection test has potential to serve as an aid in diagnosis for patients with DTD masses. This type of testing may provide clinical utility in situations where tissue-based diagnosis may not be available or achievable for masses that are suspected to be malignant.

Funding Information

This study received funding from PetDx.