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

[OBJECTIVE/BACKGROUND] 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.

[METHODS] 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.

[RESULTS] 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.

[CONCLUSIONS] 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.