Margin Reanalysis With 3-Dimensional Micrographic Surgery Technique of Conventional Excision Specimens With Negative...

Area of Science:

• Dermatology
• Surgical Oncology
• Pathology

Background:

• Mohs micrographic surgery offers superior margin analysis for skin tumors, resulting in lower recurrence rates compared to conventional surgical methods.
• Routine processing of conventional excision specimens analyzes less than 0.5% of tumor margins.
• A direct comparison between conventional processing and Mohs micrographic technique for margin assessment has not been previously conducted.

Purpose of the Study:

• To compare the margin assessment accuracy of conventional nonmelanoma skin cancer excision with serial transverse sectioning ('bread-loafing') against Mohs micrographic technique.
• To identify discrepancies in margin readings between the two techniques for histopathologically confirmed negative margins via conventional methods.

Main Methods:

• Retrospective, descriptive, historical cohort study design.
• Inclusion of patients with nonmelanoma skin cancers treated with conventional excision and negative margin readings between 2010 and 2013.
• Dewaxing and processing of original surgical specimens using the 3-dimensional Mohs micrographic technique for comparative analysis.

Main Results:

• Analysis of 101 basal cell carcinomas and 26 squamous cell carcinomas revealed 13 positive fragments (11 patients, 8.7%) initially reported as negative.
• Lateral margins were the most frequently affected sites in false-negative cases (81.8%).
• No significant association was found between false-negative margin results and specific histopathologic types or subtypes of skin cancer.

Conclusions:

• The 'bread-loafing' technique for processing conventional surgical excisions can lead to inaccurate reporting of tumor margin status.
• Mohs micrographic surgery demonstrates superior accuracy in margin evaluation for nonmelanoma skin cancers.
• Mohs micrographic surgery should be considered the gold standard for margin assessment in skin cancer treatment.