Characterization of recurrence patterns and outcomes of medulloblastoma in adults: The University of Texas MD Anderson Cancer Center experience

Background

Medulloblastoma in adults is rare and treatment decisions are largely driven from pediatric literature. We sought to characterize recurrent medulloblastoma in adults.

Methods

From a single-institution dataset of 200 adult patients diagnosed with medulloblastoma during 1978-2017, those with recurrence were analyzed for clinical features, treatment, and outcome.

Results

Of the 200 patients, 82 (41%) with median age of 29 years (18-59) had recurrence after a median follow-up time of 8.4 years (95% CI = 7.1, 10.3). Of these, 30 (37%) were standard-risk, 31 (38%) were high-risk, and 21 (26%) had unknown-risk diseases at the time of initial diagnosis. Forty-eight (58%) presented with recurrence outside the posterior fossa, of whom 35 (43%) had distant recurrence only. Median Progression-free survival (PFS) and OS from initial surgery were 33.5 and 62.4 months, respectively. Neither PFS nor OS from initial diagnosis differed between the standard-risk and high-risk groups in those who experience recurrence (P = .505 and .463, respectively). Median OS from first recurrence was 20.3 months, also with no difference between the standard-risk and high-risk groups (P = .518). Recurrences were treated with combinations of re-resection (20 patients; 25%), systemic chemotherapy (61 patients; 76%), radiation (29 patients; 36%), stem cell transplant (6 patients; 8%), and intrathecal chemotherapy (4 patients; 5%). Patients who received radiation at recurrence had better OS (32.9 months) than those who did not (19.2 months) (P = .034).

Conclusions

Recurrent medulloblastoma in adults has a poor prognosis irrespective of initial risk stratification. Recurrence commonly arises outside the posterior fossa years after initial diagnosis.

Clinical characterization of adult medulloblastoma and the effect of first-line therapies on outcome; The MD Anderson Cancer Center experience

Background

Adult medulloblastoma (MB) is rare, and management guidelines are largely based on pediatric clinical trials and retrospective series. Limited data exist with respect to clinical characteristics, prognostic factors, and outcomes based on first-line treatments.

Methods

Two hundred adults with MB seen at a single institution from January 1978 to April 2017 were identified and followed for a median of 8.4 y (7.1, 10.3).

Results

Patient’s median age at diagnosis was 29 y (18, 63). One hundred eleven (55.5%) were standard-risk, 59 (29.5%) were high-risk, and 30 (15.0%) were indeterminate. Most received post-operative radiation (RT) (184 [92.0%]), and 105 (52.5%) received first-line chemotherapy. Median overall survival (OS) was 8.8 y (7.2, 12.2) and median progression-free survival (PFS) was 6.6 y (4.9, 11.2). High-risk patients had inferior OS (Hazard ratio [HR] = 2.5 [1.5, 4.2], P = .0006) and PFS (HR = 2.3 [1.3, 3.9], P = .002) compared to standard-risk patients. Age, sex, and metastatic disease were not associated with survival. After adjusting for risk status, those who received RT plus adjuvant chemotherapy had superior PFS compared to RT plus neoadjuvant chemotherapy [HR = 0.46 (0.22, 0.95), P = .0357]. Within a subgroup for whom detailed clinical data were available, those who received RT plus adjuvant chemotherapy had improved PFS compared to RT only [HR = 0.24 (0.074–0.76), P = .016]. The substitution of cisplatin for carboplatin and the elimination of vincristine did not negatively affect outcomes.

Conclusion

This is the largest single-institution retrospective study of adult MB to our knowledge and identifies standard-risk status, first-line RT and adjuvant chemotherapy as factors associated with improved outcomes.

Longitudinal molecular trajectories of diffuse glioma in adults

The evolutionary processes that drive universal therapeutic resistance in adult patients with diffuse glioma remain unclear1,2. Here we analysed temporally separated DNA-sequencing data and matched clinical annotation from 222 adult patients with glioma. By analysing mutations and copy numbers across the three major subtypes of diffuse glioma, we found that driver genes detected at the initial stage of disease were retained at recurrence, whereas there was little evidence of recurrence-specific gene alterations. Treatment with alkylating agents resulted in a hypermutator phenotype at different rates across the glioma subtypes, and hypermutation was not associated with differences in overall survival. Acquired aneuploidy was frequently detected in recurrent gliomas and was characterized by IDH mutation but without co-deletion of chromosome arms 1p/19q, and further converged with acquired alterations in the cell cycle and poor outcomes. The clonal architecture of each tumour remained similar over time, but the presence of subclonal selection was associated with decreased survival. Finally, there were no differences in the levels of immunoediting between initial and recurrent gliomas. Collectively, our results suggest that the strongest selective pressures occur during early glioma development and that current therapies shape this evolution in a largely stochastic manner.

The molecular landscape of glioma in patients with Neurofibromatosis 1

Neurofibromatosis type 1 (NF1) is a common tumor predisposition syndrome in which glioma is one of the prevalent tumors. Gliomagenesis in NF1 results in a heterogeneous spectrum of low- to high-grade neoplasms occurring during the entire lifespan of patients. The pattern of genetic and epigenetic alterations of glioma that develops in NF1 patients and the similarities with sporadic glioma remain unknown. Here, we present the molecular landscape of low- and high-grade gliomas in patients affected by NF1 (NF1-glioma). We found that the predisposing germline mutation of the NF1 gene was frequently converted to homozygosity and the somatic mutational load of NF1-glioma was influenced by age and grade. High-grade tumors harbored genetic alterations of TP53 and CDKN2A, frequent mutations of ATRX associated with Alternative Lengthening of Telomere, and were enriched in genetic alterations of transcription/chromatin regulation and PI3 kinase pathways. Low-grade tumors exhibited fewer mutations that were over-represented in genes of the MAP kinase pathway. Approximately 50% of low-grade NF1-gliomas displayed an immune signature, T lymphocyte infiltrates, and increased neo-antigen load. DNA methylation assigned NF1-glioma to LGm6, a poorly defined Isocitrate Dehydrogenase 1 wild-type subgroup enriched with ATRX mutations. Thus, the profiling of NF1-glioma defined a distinct landscape that recapitulates a subset of sporadic tumors.