'Inverse association between the total naevus count and melanoma thickness'.

Area of Science:

• Dermatology
• Oncology
• Epidemiology

Background:

• High total naevus count (TNC) is a known risk factor for melanoma.
• Melanomas in patients with numerous nevi may be thinner, and nodular melanoma is linked to a low naevus count.

Purpose of the Study:

• To investigate the association between total naevus count (TNC) and melanoma Breslow thickness.
• To explore the relationship between TNC and melanoma invasiveness.

Main Methods:

• A retrospective study of 326 melanoma patients from two tertiary centers (2016-2018).
• Analysis of melanoma incidence (in situ vs. invasive) and correlation with TNC.
• Mean patient age was 58.3 years, with a majority being male.

Main Results:

• Patients with in situ melanoma had a higher mean TNC (57.2) compared to invasive melanoma (31.5).
• In situ melanoma showed a higher TNC across all ages.
• For invasive melanoma, TNC was inversely associated with Breslow thickness; each additional nevus decreased invasive disease likelihood by 4%.

Conclusions:

• Higher total naevus count (TNC) is associated with thinner melanomas.
• Increased TNC correlates with a higher incidence of in situ melanoma.
• These associations are independent of patient age and sex.