Similar local recurrence and survival in patients with T1 radial growth phase melanoma on head and neck treated with 5 or 10 mm margins: A retrospective study.

Abstract

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. 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. 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. 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). 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.