Multiple Primaries: Differences in Survival of Patients with Glioma with or Without Second Malignancies.

BACKGROUND AND OBJECTIVES: The biological behavior of gliomas is influenced by various factors including molecular features and treatment response. This study investigates the prognostic implications of a second tumor in patients with glioma at time of diagnosis. Given the increasing number of patients presenting with multiple primary malignancies due to improved cancer survival and diagnostic accuracy, understanding the influence of double tumor burden on glioma outcomes is of growing clinical relevance. METHODS: We retrospectively analyzed adult patients with intracranial gliomas (WHO grade 2-4), who were surgically treated between 2015 and 2022 at our institution. Patients were categorized into two groups: glioma only and glioma plus additional solid malignancy. We compared progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier and Cox regression analyses. RESULTS: Among 426 glioma patients, 75 (17.6%) harbored a second non-brain tumor. Patients with multiple primaries showed significantly poorer OS (median 6 vs. 14 months, p = 0.002). No significant difference in PFS or OS was observed for patients in case the systemic tumor was in complete remission as compared to those with sole glioma. However, patients with progressive or stable systemic tumor had significantly worse outcomes regarding OS (p < 0.05). CONCLUSIONS: Our findings suggest that the presence of a second systemic malignancy is an independent prognostic factor for worse outcome. Further studies are mandated to elucidate genetic situations and refine therapeutic strategies for these patients.