Age is a major determinant for poor prognosis in patients with pilocytic astrocytoma: a SEER population study

Tectal glioma: clinical, radiological, and pathological features, and the importance of molecular analysis

Tectal glioma (TG) is a rare lower grade glioma (LrGG) that occurs in the tectum, mainly affecting children. TG shares pathological similarities with pilocytic astrocytoma (PA), but recent genetic analyses have revealed distinct features, such as alterations in KRAS and BRAF. We conducted a retrospective review of cases clinically diagnosed as TG and treated at our institute between January 2005 and March 2023. Six cases were identified and the median age was 30.5 years. Four patients underwent biopsy and two patients underwent tumor resection. Histological diagnoses included three cases of PA, one case of astrocytoma, and two cases of high-grade glioma. The integrated diagnosis, according to the fifth edition of the World Health Organization Classification of Tumours of the central nervous system, included two cases of PA and one case each of diffuse high-grade glioma; diffuse midline glioma H3 K27-altered; glioblastoma; and circumscribed astrocytic glioma. Among the three patients who underwent molecular evaluation, two had KRAS mutation and one had H3-3A K27M mutation. Our results demonstrate the diverse histological and molecular characteristics of TG distinct from other LrGGs. Given the heterogeneous pathological background and the risk of pathological progression in TG, we emphasize the importance of comprehensive diagnosis, including molecular evaluation.

Efficacy of various extent of resection on survival rates of patients with pilocytic astrocytoma: based on a large population

Pilocytic astrocytoma (PA) is classified as a Grade I benign neuroglial tumor. The extent of surgical resection is a critical factor influencing the prognosis for patients with PA. In prior researches of PA, the extent of surgical resection is generally categorized into GTR, STR and biopsy. In some researches on brain tumor surgeries, the extent of resection also includes GTL. There is no existing research specifically comparing the efficacy of GTR versus GTL in PA treatment. In this study, the data we used are from the SEER database. We categorized the extent of resection into GTL, GTR, STL, STR, biopsy, and no surgery based on SEER classification of surgical procedures, to investigate the impact of extent of resection on PA patient survival. A multivariate logistic regression model was utilized to acquire odds ratios (OR) for different extent of resection. Survival outcomes across different extent of resection (GTL, GTR, STL, STR, biopsy, no surgery) were assessed using Kaplan-Meier survival curve analysis, with curve comparisons conducted via log-rank tests. The impact of various risk factors on survival was assessed using the Cox proportional hazards model. The hazard ratio (HR) was employed to quantify the influence of one or more factors on overall survival throughout the follow-up period. Multivariate Cox analysis revealed that age, tumor location, extent of resection, as well as the application of radiotherapy and chemotherapy, all significantly impacted prognosis. Compared to GTL, GTR did not significantly increase the risk of mortality (HR 1.17; 95% CI 0.73-1.86, p = 0.5). Furthermore, there was no statistically significant difference between the Kaplan-Meier survival curves of the two groups (p = 0.18). We employed propensity score matching (PSM) to balance the differences in baseline characteristics of patients receiving chemotherapy or radiotherapy. A total of 4429 patients were included in this study. Age, diagnosis period, race, tumor size, and tumor location as influential on the extent of resection. Age, tumor location, extent of resection, and application of radiotherapy and chemotherapy influenced the survival of PA patients. The Kaplan-Meier survival curves revealed that the long-term survival rate for GTR is slightly higher than that for GTL. The PSM analysis revealed that the application of radiotherapy and chemotherapy was associated with the reduction of overall survival in PA patients. In conclusion, there was no significant difference in survival between GTR and GTL, so GTR with less damage was preferred. The application of radiotherapy and chemotherapy can reduce overall survival of patients with PA.

Integrative multi-omics reveals two biologically distinct groups of pilocytic astrocytoma

Pilocytic astrocytoma (PA), the most common pediatric brain tumor, is driven by aberrant mitogen-activated protein kinase signaling most commonly caused by BRAF gene fusions or activating mutations. While 5-year overall survival rates exceed 95%, tumor recurrence or progression constitutes a major clinical challenge in incompletely resected tumors. Here, we used similarity network fusion (SNF) analysis in an integrative multi-omics approach employing RNA transcriptomic and mass spectrometry-based proteomic profiling to molecularly characterize PA tissue samples from 62 patients. Thereby, we uncovered that PAs segregated into two molecularly distinct groups, namely, Group 1 and Group 2, which were validated in three non-overlapping cohorts. Patients with Group 1 tumors were significantly younger and showed worse progression-free survival compared to patients with group 2 tumors. Ingenuity pathways analysis (IPA) and gene set enrichment analysis (GSEA) revealed that Group 1 tumors were enriched for immune response pathways, such as interferon signaling, while Group 2 tumors showed enrichment for action potential and neurotransmitter signaling pathways. Analysis of immune cell-related gene signatures showed an enrichment of infiltrating T Cells in Group 1 versus Group 2 tumors. Taken together, integrative multi-omics of PA identified biologically distinct and prognostically relevant tumor groups that may improve risk stratification of this single pathway driven tumor type.