Prognostic factors in malignant thymic neoplasms: A comprehensive real-world analysis from a Brazilian tertiary center.

Abstract

e20174 Background: Malignant thymic neoplasms are rare and biologically heterogeneous tumors, with limited prospective data to guide prognostic stratification. Real-world cohorts incorporating clinical, radiological, pathological, and laboratory variables may help clarify which factors truly drive outcomes. Methods: We conducted a retrospective single-center study including patients with malignant thymic neoplasms treated at a Brazilian tertiary cancer center. Variables collected included demographic and clinical characteristics, comorbidities (Charlson Comorbidity Index, CCI), autoimmune disease, radiological features, tumor stage, histological subtype, surgical treatment, and laboratory parameters (BMI, lactate dehydrogenase, neutrophil-to-lymphocyte ratio, and platelet count). Associations with surgery, recurrence, and death were assessed using chi-square or Fisher’s exact tests and non-parametric tests as appropriate. Overall survival (OS) was estimated using Kaplan–Meier and compared with the log-rank test. Results: Forty-eight patients were included, with balanced sex distribution and a high prevalence of autoimmune disease, particularly myasthenia gravis. Approximately 60% underwent surgical resection, most with complete (R0) margins. Surgery was significantly associated with myasthenia gravis, earlier stage, absence of nodal involvement, less aggressive histology, and smaller tumor size. Recurrence was infrequent and showed no consistent associations. Death was associated with higher CCI (≥2), symptomatic presentation, lower BMI, and aggressive histology. Median OS was 139 months. Patients with B3 thymoma or thymic carcinoma had significantly worse OS compared with other histological subtypes (log-rank p = 0.006), while cancer-specific death was rare among non-B3/C tumors. Conclusions: Histological subtype—particularly B3 thymoma and thymic carcinoma—emerged as the dominant prognostic determinant in malignant thymic neoplasms. Higher CCI, symptomatic presentation, and lower BMI were also associated with mortality. Cancer-specific death was uncommon outside aggressive subtypes, reinforcing the central role of histology and stage in risk stratification and clinical decision-making.