Survival between synchronous and non-synchronous multiple primary cutaneous melanomas-a SEER database analysis

Area of Science:

• Oncology
• Dermatology
• Biostatistics

Background:

• Distinguishing synchronous and non-synchronous multiple primary cutaneous melanomas (MPMs) lacks established criteria.
• Accurate differentiation is crucial for prognostic assessment and treatment planning in melanoma patients.

Purpose of the Study:

• To establish criteria for distinguishing synchronous from non-synchronous MPMs.
• To compare the survival outcomes between synchronous and non-synchronous MPMs.
• To identify the prognostic significance of synchronous MPM occurrence.

Main Methods:

• Utilized the Surveillance, Epidemiology, and End Results (SEER) database.
• Applied piecewise linear regression to the time interval between first and second primary cutaneous melanomas (TIFtS) distribution.
• Employed Kaplan-Meier and Cox proportional hazard models for survival analysis, treating synchronous MPM occurrence as a time-dependent variable.

Main Results:

• The time interval distribution suggested a 2-month threshold for defining synchronous MPMs.
• Synchronous MPMs demonstrated significantly inferior overall and melanoma-specific survival compared to non-synchronous MPMs (P < 0.0001).
• The occurrence of synchronous MPM was identified as a significant risk factor for overall survival in cutaneous melanoma (HR: 2.213, P < 0.0001).

Conclusions:

• Provides data-driven evidence supporting the use of a 2-month interval to differentiate synchronous MPMs.
• Confirms that synchronous MPM occurrence is a critical risk factor impacting patient prognosis in cutaneous melanoma.