An international survey characterizing Mohs tissue processing techniques and Mohs margin thresholds: how close is too...

Area of Science:

• Dermatology
• Surgical Oncology
• Pathology

Background:

• Identified heterogeneity in Mohs micrographic surgery (MMS) specimen tissue processing and histological tumor clearance assessment.
• Variations exist among Mohs surgeons regarding tissue handling and interpretation of surgical margins.

Purpose of the Study:

• To characterize the variation in margin threshold assessment among an international cohort of Mohs surgeons.
• To determine the number of tumor-free sections required to declare clearance in Mohs micrographic surgery.

Main Methods:

• An international online questionnaire was distributed to Mohs surgeons.
• Assessed surgeon demographics, Mohs micrographic surgery tissue processing techniques, and margin threshold definitions.
• Presented three clinical scenarios to evaluate margin assessment practices.

Main Results:

• 114 surgeons from 20 countries responded.
• Significant variation in the number of clear sections required for tumor clearance was observed across different tumor types and presentations (e.g., basal cell carcinoma, squamous cell carcinoma).
• Standardization in tissue processing (5-10 μm sections) and trimming intervals (20-200 μm) was reported by a majority of respondents.

Conclusions:

• International Mohs surgeons exhibit diverse approaches to margin threshold assessment and tissue processing.
• Highlighting surgeon background characteristics and peer-comparison of margin assessment practices.
• Delineates variations in tissue processing and intraoperative decision-making in Mohs micrographic surgery.