Recurrence and metastasis of cutaneous and subcutaneous tumors following excision with advanced surgical margin assessment.

Background: Surgical margin status can affect the risk for recurrence in dogs with cutaneous and subcutaneous masses. Histopathology is the current gold standard for margin assessment, despite evaluating small amounts of the surgical margin. Optical coherence tomography (OCT) has been described for surgical margin assessment following the excision of canine cutaneous and subcutaneous tumors.

Objective: To assess the rates of recurrence and metastasis following excision with an incomplete margin on OCT and confirmed with histopathology.

Animals and procedure: Seventy-one excised canine cutaneous and subcutaneous tumors underwent OCT imaging and histopathologic assessment.

Results: Of 61 tumors, 51 were malignant, including 21 soft tissue sarcomas and 21 mast cell tumors. Ten dogs experienced local tumor recurrence, with 7/10 and 8/10 having incomplete margins on OCT and histopathology, respectively. Ten dogs experienced distant metastasis, with 6/10 and 8/10 having incomplete margins on OCT and histopathology, respectively.

Conclusion and clinical relevance: Local recurrence occurred in tumors with predominately incomplete margins following advanced surgical margin assessment; however, not all tumors with incomplete margins developed local recurrence. Further prospective research is needed to assess the effect of entire surgical margin imaging on patient outcomes.