TOPLINE:

In a retrospective cohort study, the anatomical site of the tumor predicted the initial route of metastasis in patients with early-stage acral lentiginous melanoma (ALM).

METHODOLOGY:

• Researchers conducted a retrospective cohort analysis of 281 patients (56.9% women) with early-stage ALM (77 with stage 0, 90 with stage I, and 114 with stage II disease), diagnosed between 1997 and 2024 at Asan Medical Center, Seoul, South Korea.
• A total of 83 upper-limb tumors (6 palms, 12 fingers, and 77 fingernails) and 198 lower-limb tumors (184 soles, 27 toes, and 53 toenails) were included.
• Participants underwent routine imaging surveillance including computed tomography and sentinel lymph node ultrasonography.
• The researchers evaluated first metastasis sites and prognostic factors for lymph node and systemic spread.

TAKEAWAY:

• First lymph node metastasis occurred more often in lower-limb melanomas vs upper-limb ALM (22.7% vs 10.8%; P = .021), whereas first distant metastasis was notably more common in upper-limb ALM (14.5% vs 4.5%; P = .004).
• Upper-limb location (hazard ratio [HR], 4.651; P = .003), ulceration (HR, 4.904; P = .005), and lymphovascular invasion (HR, 24.108; P < .001) were independent predictors of systemic metastasis-free survival.
• In patients with stage II disease, upper-limb vs lower-limb location was significantly associated with higher rates of first distant metastasis (36.0% vs 9.0%; P = .002), while first lymph node metastasis was more frequent in lower-limb cases (39.3% vs 20.0%; P = .074).
• In nail unit melanoma, fingernail vs toenail tumors showed higher systemic spread (first distant metastasis, 14.7% vs 0%; P = .013; final distant metastasis, 17.9% vs 2.6%; P = .029). Toenail vs fingernail tumors had greater lymph node involvement (30.0% vs 10.3%, P = .009).

IN PRACTICE:

“Our findings suggest that the first metastatic pattern differs significantly based on tumor location (upper limb vs lower limb) in early stage ALM, with the most notable differences seen” with nail unit melanomas, the authors concluded. “If validated in future prospective studies,” they added, “these location-based variations may support the implementation of tailored surveillance strategies, emphasizing either visceral or lymphatic surveillance during follow-up for patients with early-stage ALM.”

SOURCE:

The study was led by Myoung Eun Choi, MD, Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, and was published online on October 22 in the Journal of the American Academy of Dermatology.

LIMITATIONS:

This study was limited by the retrospective design, selection and referral bias, variations in follow-up duration and imaging protocols, and relatively small sample size.

DISCLOSURES:

The authors reported having no funding sources or relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.