Microsatellitosis in Patients with Melanoma

Area of Science:

• Oncology
• Dermatology
• Surgical Pathology

Background:

• Microsatellitosis (mS) in melanoma is often linked to poor prognosis, but studies are limited.
• Current staging (IIIB/C/D) may not fully capture mS behavior.
• This study aimed to clarify outcomes and prognostic factors in mS with comprehensive nodal staging.

Purpose of the Study:

• To characterize outcomes and prognostic factors in patients with melanoma microsatellitosis (mS).
• To compare melanoma-specific survival (MSS) in mS patients with a larger registry cohort.
• To evaluate the impact of sentinel lymph node (SLN) status on mS prognosis.

Main Methods:

• Analysis of a multi-institutional cohort of 414 patients with mS undergoing sentinel lymph node (SLN) biopsy.
• Utilized Cox regression to identify prognostic factors for melanoma-specific survival (MSS).
• Compared MSS of mS patients with 3002 similarly staged patients from the SEER Program.

Main Results:

• Key prognostic factors for poorer MSS included increasing tumor thickness, male sex, and SLN positivity.
• Five-year MSS rates for stages IIIB, IIIC, and IIID were 86.3%, 54.1%, and 44.2%, respectively.
• Stage IIIB mS patients demonstrated significantly better survival than a comparable SEER cohort, unlike stages IIIC/D.

Conclusions:

• Sentinel lymph node metastases are frequent and significantly impact prognosis in melanoma with mS.
• Stage IIIB melanoma with mS has a more favorable survival than predicted by current staging.
• Findings suggest a need to reconsider adjuvant therapy decisions for stage IIIB mS patients.