Clinical Versus Dermoscopic Evaluation of Tumor Margins Prior to Surgical Excision-A Systematic Review

Background/Objectives: Accurate surgical margin delineation is essential in the treatment of non-melanoma skin cancers (NMSCs), particularly basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC), to reduce recurrence and metastasis. Dermoscopy improves diagnostic accuracy for skin tumors, but its utility for preoperative margin assessment remains underexplored. To compare dermoscopy-guided versus clinical visual inspection for preoperative margin assessment in NMSC excision, focusing on histological clearance rates and surgical outcomes. Methods: This systematic review and meta-analysis followed PRISMA 2020 guidelines. MEDLINE, Cochrane CENTRAL, Scopus, and Web of Science were searched from inception to 1 July 2025. Eligible studies included adult patients undergoing surgical excision of histologically confirmed BCC or cSCC, with preoperative margin evaluation using either dermoscopy or clinical examination. The primary outcome was the rate of complete histological excision. Study quality was assessed using the Newcastle-Ottawa Scale. A random-effects meta-analysis using the Freeman-Tukey transformation was performed. Results: Nine cohort studies comprising 900 NMSC lesions were included. Dermoscopy-guided excision demonstrated pooled histological clearance of 98.7% (95% CI: 97-99.8%), compared to 80-94% with clinical assessment. Moderate heterogeneity was observed (I² = 42%). However, variability in study design and limited data for cSCC restricted broader conclusions. Conclusions: Dermoscopy may enhance margin assessment and histological clearance in NMSC surgery, especially for BCC. Further standardized, high-quality studies are needed to confirm its role in surgical planning and extend evidence to SCC.