A Simplified Classification System for In-Transit Melanoma Metastases

Area of Science:

• Oncology
• Dermatology
• Surgical Pathology

Background:

• In-transit metastases (ITMs) from cutaneous melanoma exhibit heterogeneous behavior and are difficult to manage.
• Current prognostic models lack specificity for ITMs, hindering optimal treatment and clinical trial design.

Purpose of the Study:

• To identify prognostic factors for disease-specific survival (DSS) in patients with cutaneous melanoma in-transit metastases.
• To develop criteria for a risk-stratification system for ITMs.

Main Methods:

• A prospective database of 142 melanoma patients with ITMs was analyzed.
• Disease-specific survival (DSS) and distant metastasis-free survival were primary outcomes.
• Multivariable analysis and threshold analysis identified key prognostic variables.

Main Results:

• A longer ITM-free interval correlated with improved DSS.
• Increased number of ITMs and greater Breslow thickness were associated with shorter DSS.
• Larger ITMs and synchronous regional disease predicted worse distant metastasis-free survival.

Conclusions:

• Patients with >2 ITMs, ITMs >30 mm, an ITM-free interval ≤18 months, or synchronous regional disease face higher risks.
• These factors can inform risk stratification for melanoma ITMs.