The presence of microsatellites with primary melanomas was associated with a decreased overall survival, melanoma-specific survival, and disease free-survival (p<0.001).
Clinical Pearls
This was a retrospective bicenter cohort study which sought to evaluate survival outcomes in patients diagnosed with melanoma and microsatellites
Primary melanomas with microsatellites frequently occurred with nodal metastases detected using SLNB (25.9%), in-transit or nodal macrometastasis (28.7%), and distant metastasis (10.2%)
The presence of microsatellites with primary melanomas was associated with a decreased overall survival, melanoma-specific survival, and disease free-survival (p<0.001)
Discussion:
Microsatellites in cutaneous melanoma are included as a relevant prognostic factor in the current, eight edition of the American Joint Committee on Cancer (AJCC) guidelines. Although their presence has thought to indicate aggressive behavior of disease, there is currently limited data to support considering them as an independent risk factor.
The primary objectives of this study by Riquelme-Mc Loughlin et al. were to compare the basal characteristics of patients with melanoma with and without microsatellites, compare the survival outcomes of patients with melanoma with and without microsatellites, and evaluate the role of microsatellites in terms of outcomes in patients with stage III melanoma while also analyzing the relevance of microsatellites in the AJCC eight edition classification system as compared with the seventh edition. Finally, this study sought to evaluate the role of SLNB in melanoma with microsatellites.
This study analyzed 5,216 patients of which 108 had melanoma with microsatellites. The presence of microsatellites was frequently found with other conditions such as nodal metastases detected via SLNB (25.9%), in-transit or macrometastasis (28.7%), and distant metastasis (10.2%). In both univariate and multivariate Cox regression analysis, the presence of microsatellites was associated with worse overall survival, melanoma-specific survival, and disease-free survival (p<0.001 in all analyses). When looking at patients with stage 3b melanoma according to both the AJCC seventh and eight editions, the presence of microsatellites was associated with a worse 5-year overall survival than those without. Finally, when keeping in mind both the tumors with and without microsatellites and results of SLNB, the study found that the worst survival outcomes occurred in those with microsatellites and a positive SLNB.
Overall, this study provides data to support the consideration of microsatellite presence in invasive cutaneous melanomas as an independent adverse prognostic factor. Limitations include the retrospective design and that the definition of microsatellites has changed over the years of the study.
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