Surgical Excision Margins in Skin Melanomas with Breslow Thickness Greater than 2 mm: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to evaluate the efficacy of narrow compared to wide surgical excision margins in the treatment of cutaneous malignant melanomas (MM) with Breslow thickness greater than 2 mm. All prior meta-analyses included studies analyzing patients with a variety of Breslow indexes. There is no prior meta-analysis analyzing the survival of the subgroup of MM patients with MMs > 2 mm in Breslow thickness. Hence, the aim of the present meta-analysis and systematic review was to examine the survival of the subgroup of MM patients with MMs > 2 mm in Breslow thickness.

We followed the Cochrane Handbook for Systematic Reviews of Interventions and reported our findings in accordance with PRISMA guidelines. We included randomized controlled trials (RCTs) that compared narrow (1-2 cm) versus wide (3-4 cm) surgical excision margins for cutaneous melanomas thicker than 2 mm. Studies on non-cutaneous melanomas, observational studies, and non-randomized trials were excluded. Ten-year mortality rate and overall survival were the primary outcomes. Our searches were conducted in EMBASE and PUBMED databases.

Three RCTs were included, with a total of 2,304 randomized patients. This meta-analysis showed no significant difference in 10-year all-cause mortality between narrow (2 cm) and wide (4 cm) margins (risk difference: 3.3%, 95% CI: -1.7% to 8.2%, p=0.202). Similarly, there was no significant difference in overall survival between narrow (1-2 cm) and wide (3-4 cm) margins (hazard ratio: 1.09, 95% CI: 0.974-1.214, p=0.3). Heterogeneity was low and non-significant.

This meta-analysis supports the non-inferiority of narrow (1-2 cm) surgical margins compared to wide (3-4 cm) margins for localized cutaneous melanomas with Breslow thickness greater than 2 mm. These findings suggest that narrow margins could be considered in surgical practice, although a 1 cm margin may be inadequate based on the results of individual studies. Further RCTs focusing on patients with localized MM thicker than 2 mm and taking into account modern adjuvant therapies and sentinel lymph node biopsies are recommended to refine surgical guidelines.