Comparison of 1-cm Versus 2-cm Excision Margins for Cutaneous Melanoma: A Systematic Review and Meta-Analysis.

Surgical intervention is the primary treatment for localised cutaneous melanoma, with wide local excision being the gold standard. However, optimal excision margins remain a point of debate amongst clinicians. This systematic review and meta-analysis evaluated the outcomes of 1 cm versus 2 cm excision margins for intermediate to thick melanomas. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a search of databases including PubMed, Medline, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and the Cochrane Central Register of Controlled Trials (CENTRAL) was conducted. The World Health Organization International Clinical Trials Registry, ClinicalTrials.gov, the ISRCTN registry and Science Direct were also screened. Seven studies met the inclusion criteria. Primary outcomes included overall, locoregional, and distant melanoma recurrence rates between 1 cm and 2 cm margins. Secondary outcomes assessed five-year disease-free survival and reconstruction complexity. The results were presented with forest plots at 95% confidence interval.  No significant difference in overall recurrence rate was observed between 1 cm and 2 cm margins (0.846; 0.649, 1.103, p=0.216). Three studies reported no significant difference in disease-free survival at final follow-up. Primary closure was more achievable with a 1 cm margin (1.300; 1.053, 1.605, p value <0.015), while 2 cm margins required more complex reconstructions such as local flaps or skin grafts (0.772; 0.625, 0.955, p< 0.017). This systematic review and meta-analysis suggests that a 1 cm margin is as safe as a 2 cm margin for intermediate to thick melanomas, reducing the need for complex reconstructions. Further randomised controlled trials are recommended to solidify these findings, but this study provides a strong foundation for adopting smaller excision margins.