Risk of recurrence of nail unit melanoma after functional surgery versus amputation

Abstract

Background: Minimally invasive nail unit melanoma (NUM) can be treated with functional surgery (FS) instead of amputation. Objective: To determine risk factors associated with recurrence in NUM. Methods: We retrospectively reviewed patients with NUM between 2008 and 2022 at a tertiary referral center. Multivariable Cox regression models adjusted for male sex and Breslow thickness (BT) were generated. Receiver operating characteristic analysis was performed to determine optimal cut-off points of the BT for stratifying recurrence risk. Results: We evaluated 140 NUM cases (33 amputation and 107 FS). The mean BT values were 3.14 +/- 2.62 mm (amputation) and 0.70 +/- 1.36 mm (FS). Recurrence occurred in 10 (30.30%) patients with amputation and 23 (21.5%) with FS. Distant disease occurred in 10 (30.30%) patients with amputation and 8 (7.48%) with FS. Male sex, greater BT, amelanotic color, ulcers, and nodules were associated with greater risk for recurrence or distant disease. A BT of 0.8 mm was deemed the optimal cut-off for stratifying recurrence risk after surgery (odds ratio, 5.32; 95% CI, 2.04-13.85). Limitations: Small sample. Conclusion: FS can be considered for NUM with a BT \ 0.8 mm, providing an amputation-sparing benefit. However, NUM with risk factors for recurrence requires patient counselling and close follow-ups. ( J Am Acad Dermatol 2023;88:1017-23.)