RESUMEN
BACKGROUND: Melanoma guidelines recommend surgical excision with 10 mm margins for T1 melanomas (invasive melanomas with Breslow thickness ≤1 mm), including those in radial growth phase, which are without metastatic potential; however, such margins may be problematic on head-and-neck. OBJECTIVE: We compared outcomes of wide (10 mm margins) versus narrow (5 mm margins) excisions in patients with radial growth phase T1 melanoma on head-and-neck including face. METHODS: We retrospectively examined 610 consecutive patients excised with wide versus narrow margins, from 2001 to 2018, at six European centres. In all cases, radial growth phase, and clear margins with 5 or 10 mm of clearance, were ascertained histologically. Multivariable models investigated associations of margins and other factors with overall survival and local recurrence. RESULTS: Three hundred and sixteen (51.8%) patients received wide excision, 219 (69.3%) with primary wound closure, 97 (30.7%) with reconstruction; 294 (48.2%) patients received narrow excision, 264 (89.8%) with primary wound closure, 30 (10.2%) with reconstruction (p < 0.001). Median follow-ups were 88 months (wide) and 187 months (narrow) (inter-quartile ranges 43-133 and 79-206, respectively). Ten-year overall survival (95% confidence interval) was 96.7% (94.2%-99.3%) in wide and 98.2% (96.4%-100%) in narrow patients. Ten-year local recurrence incidence was 6.4% (4.1%-10.1%) in wide and 7.8% (5.3%-11.6%) in narrow groups. Lentigo maligna melanoma subtype appeared associated with increased risk of local recurrence in narrow versus wide patients (15.0% vs. 7.5%; p = 0.190). CONCLUSIONS: Narrower excision margins for T1 radial growth phase melanoma are not associated with worse overall survival (hazard ratio 0.97, p = 0.996) or increased local recurrence (subdistribution hazard ratio: 0.87; p = 0.751) compared to wider margins, and may be safely applied to such lesions, although caution may be required in the presence of lentigo maligna melanoma.