Role of tumor-infiltrating lymphocytes in melanoma prognosis and treatment strategies: A systematic review and meta-analysis

Abstract

PurposeNumerous studies underscore the relevance of tumor-infiltrating-lymphocytes (TILs) as important prognostic factors for melanoma. This meta-analysis aims to provide a comprehensive literature overview elucidating their role in predicting patient outcomes, specifically investigating the association between TIL density and prognosis. MethodsFrom an initial pool of 6094 records, 16 met the eligibility criteria, encompassing a collective cohort of 16021 patients. Data on TIL counts, clinical characteristics, and survival metrics (5-year overall survival [5yOS], 10-year overall survival [10yOS], and 5-year melanoma-specific survival [5yMSS]) were extracted from each study and expressed as proportions. Results were graphically presented using forest plots, reporting the estimates from individual studies, summary estimates, and corresponding 95 % confidence intervals (CI). ResultsAnalysis revealed a statistically significant difference in 5yOS concerning subgroup differences However, 10yOS and 5yMSS did not exhibit statistical significance. Nonetheless, a consistent trend emerged indicating a higher survival rate corresponding to increased immune cell density, ranging from absent TILs to brisk levels. ConclusionsTILs present potential as a readily applicable prognostic factor. Yet, further investigations into their density and phenotypic subpopulation characteristics could enhance our understanding of their predictive value in tailoring optimal patient-specific therapies.