Master Student: Michael Wessel
Project: ”Surgical Margins in Canine Mast Cell Tumors - A Systematic Review"
Background: Mast cell tumors (MCTs) are the most common potential malignant cutaneous tumors in dogs. MCTs tend to be well-circumscribed, solitary, and slow growing tumors. Surgery is the treatment of choice whenever it is possible. The surgical goal is wide margins, making complete excision more likely.
Objective: To evaluate the literature for evidence of the surgical margins in MCTs. Can margins less than 3 cm and 1 facial plane be accepted and still give the patient a comparable life expectancy and disease free interval?
Method: A systematic search of various electronic databases was performed to identify studies published before September 2019. Included studies were peer-reviewed articles investigating surgical and histological margins in relation to MCT removal.
Results: 12 studies were included containing 501 dogs with 578 MCTs. Among all tumors, clean histologic margins were found in 470 (81,6%) cases, dirty margins in 94 (16,3%) and unknown margins in 12 (2,1%) cases. Meta-analysis showed that the overall chance of clean histologic margins was 85,2% and the risk of recurrence was 2,9%. Removing grade I or II MCT with a surgical margin of ≤2 cm, the chance of clean histologic margins was 94,6%. For surgical margins >2 cm the chance was 82,6%.
Conclusion: Considering the unpredictable nature of which clean vs. dirty margins recur, and the potential complications and pain the patient must endure following a 3 cm surgical margin - excising a MCT with 2 cm surgical margin or less seems to be a reasonable and adequate choice.