Prognostic role of microsatellites in melanoma and implications in the American Joint Committee on Cancer classification system: A cohort study

Abstract

Background: There is limited information on microsatellite survival outcomes in patients with melanoma.

Objective: To evaluate survival outcomes in patients with microsatellites, assess their role within stage III stratification of the American Joint Committee on Cancer classification, and assess the results of sentinel lymph node biopsies in patients with microsatellites.

Methods: A retrospective bicenter cohort study from 1998 to 2019 included patients with a diagnosis of invasive cutaneous melanoma.

Results: Of a total of 5216 patients, 108 (2.1%) had microsatellites at initial staging. Survival analysis showed that microsatellites were an independent risk factor with decreased overall survival (OS), melanoma-specific survival (MSS), and disease-free survival, with hazard ratios of 1.57, 1.76, and 1.76, respectively. Stratified analysis in patients with stage III melanoma showed a 5-year OS of 35% (95% CI, 17.3%-73.4%) and a MSS of 45% (95% CI, 23.1-87.5) for patients with stage IIIB melanoma with microsatellites.

Limitations: Retrospective design of the study.

Conclusion: Microsatellites were associated with other adverse melanoma prognostic factors. A multivariate Cox regression analysis showed that they are an independent risk factor for worse OS, MSS, and disease-free survival. Patients with stage IIIB melanoma with microsatellites had worse OS and MSS, whereas patients with stage IIIC melanoma had worse OS but not MSS.

Keywords: clinical decision making; melanoma; microsatellites; prognosis; sentinel lymph node biopsy; staging.