Is head and neck melanoma a distinct entity? A clinical registry-based comparative study in 5702 patients with melanoma.

BACKGROUND: The head and neck region is more heavily exposed to ultraviolet (UV) radiation than any other body site. Therefore, cutaneous malignant melanoma (CMM) of the head and neck area is proposed to have notable differences from melanoma at other body sites regarding clinicopathological features and survival of patients.

OBJECTIVES: The present retrospective study based on clinical registry data aims to compare clinical features and prognostic factors of head and neck melanoma (HNM) vs. melanoma at other anatomical regions (MOR) in order to detect differences which may be associated to the mode of sun exposure.

METHODS: The clinical records and histopathological findings of 844 patients with clinical stage I and II invasive HNM were compared with the data of 4858 patients with MOR. Survival analysis was performed using the Kaplan-Meier estimate, and the multivariate Cox proportional hazard model was used to evaluate independent prognostic factors.

RESULTS: Melanoma density was clearly higher for HNM than for MOR: this was particularly true for the face, where it was elevated by a factor of 2.6. There was a higher male/female ratio in patients with HNM and they were significantly older than patients with MOR (P < 0.0001). Breslow tumour thickness did not differ between HNM and MOR. However, CMMs at the scalp were significantly thicker and to a higher degree ulcerated. Concerning clinicopathological CMM subtypes, there was an increased proportion of lentigo maligna melanoma among HNM and of nodular melanoma in the scalp and neck regions. Excision margins were narrower and the rate of complete primary excision was lower in HNM than in MOR. Overall, there was no significant statistical difference in cumulative 10-year survival rates according to Kaplan-Meier estimates among patients with HNM (84.6%) and MOR (87.8%). Tumour thickness turned out to be the variable with the highest prognostic impact followed by ulceration in both HNM and MOR.

CONCLUSIONS: In relation to the skin surface significantly more CMMs were found in the head and neck area than in other anatomical regions. This might indicate, but does not prove, that UV exposure promotes the development of CMM. Although HNM showed specific clinicopathological features, prognosis remained unaffected. Thus HNM seems not to be a distinct subtype of CMM.