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

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.)

Automated summary

This study retrospectively reviewed patients with Minimally invasive nail unit melanoma (NUM) and identified risk factors for recurrence. Male sex, greater Breslow thickness, amelanotic color, ulcers, and nodules were associated with higher risk of recurrence or distant disease. A Breslow thickness of 0.8 mm was determined to be the optimal cut-off point for predicting recurrence risk after surgery.