Abstract: Background- After a dog is diagnosed with cancer and receives therapy, physical examination and imaging are typically used to assess disease status and monitor for recurrence.
Hypothesis/Objectives- To evaluate the performance of a next-generation sequencing (NGS) based liquid biopsy test as an adjunct tool for cancer monitoring in dogs.
Animals- Client-owned dogs enrolled in the CANcer Detection in Dogs study that had confirmed cancer diagnoses and Cancer Signal Detected results at the pre-treatment visit.
Methods- Blood samples collected pre-treatment and following therapeutic intervention (e.g., surgery, chemotherapy, radiation, etc.) were subjected to DNA extraction, library preparation, and NGS. Sequencing data were analyzed for genomic alterations associated with the presence of cancer.
Results- Following excisional surgery, in the absence of clinical residual disease at the first post-operative visit, patients with Cancer Signal Detected (CSD) results at that visit were twice as likely to have clinical recurrence within 6 months, compared to patients with Cancer Signal Not Detected results. For patients that achieved complete response following therapy, a CSD result was issued prior to or concomitant with clinical recurrence in 70% of cases that experienced clinical recurrence during the study period. Overall, >95% of samples with CSD at a follow-up visit had clinical disease at that visit or at a later visit.
Conclusions and clinical importance- NGS-based liquid biopsy has the potential to improve monitoring of cancer in dogs. Patients with no clinical evidence of disease but with molecular evidence of disease may benefit from closer clinical evaluation and monitoring.
