OS05.5.A Methylation analysis of matched primary and recurrent IDHmt astrocytoma; an update from the Glioma Longitudinal Analysis NL (GLASS-NL) consortium

BACKGROUND

The evolutionary processes that drive progression in patients with IDH-mutant astrocytoma remain unclear. The GLASS-NL consortium, as part of the larger worldwide GLASS consortium, was initiated to gain insight into the molecular mechanisms underlying glioma evolution and to identify markers of progression in IDH-mutant astrocytomas. Such markers can ultimately assist clinical decision making. Here, we present the first results of genome wide methylation profiling of samples included in the GLASS-NL study.

MATERIAL AND METHODS

110 adult patients were identified with an IDH-mutant astrocytoma at first diagnosis. All patients underwent a surgical resection of the tumor at least twice, separated by at least 6 months with a median of 40.9 months (IQR: 24.0, 64.7), in 37% and 18% of the cases, patients were treated with radiotherapy or chemotherapy respectively, before surgical resection of the recurrent tumor. Methylation profiling was done on (macro dissected) DNA isolated of 235 samples from 103 patients (102 1st, 101 2nd, 29 3rd, and 3 4th resection), using the Infinium MethylationEPIC BeadChip array. Copy number variations were also derived from these data. Methylation classes were determined according to Capper et al. (2018). Overall survival (OS) was measured from date of first surgery.

RESULTS

Of all primary tumors, the methylation-classifier assigned 85 (87%) to the A_IDH (‘low grade’) subclass and 10 (10%) to the A_IDH_HG (‘high grade’) subclass. The relative proportion of high grade tumors increased ~three-fold at tumor recurrence (32/101, 32%) and even further in the second recurrence (15/29, 52%). The overall DNA-methylation levels of recurrent samples was lower than that of primary samples. This difference is explained by the increased number of high grade samples at recurrence, since near identical DNA-methylation levels were observed in samples that remained low grade. In an unsupervised analysis, methylation data derived from first and second resections of individual patients mostly (79%) cluster together. This indicates that variability between tumors is larger than temporal heterogeneity within tumors. Recurrent samples that do not cluster with their primary tumor, form a separate cluster and have relatively low genome-wide DNA-methylation.

CONCLUSION

Our data demonstrate that methylation profiling identifies a shift towards a higher grade at tumor progression coinciding with reduced genome-wide DNA-methylation levels.

OS09.4.A Health-related quality of life in low-grade glioma survivors 26 years after diagnosis

BACKGROUND

Many patients with low-grade gliomas (LGGs) continue to survive for many years, yet little is known about patients’ health-related quality of life (HRQOL) in long-term survivorship. We previously investigated HRQOL in LGG patients diagnosed on average 6 years prior to assessment (T1, N=195) with a follow-up in stable patients on average 12 years after diagnosis (T2, N=65). We present a final follow-up of LGG survivors (T3), now decades after diagnosis.

MATERIAL AND METHODS

We invited patients who participated in our previous assessment (N=65), regardless of disease status. Patients completed questionnaires to assess HRQOL, fatigue, and depressive symptoms: Short Form-36 Health Survey (SF-36), European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Brain Tumour Module (EORTC BN20), Checklist Individual Strength (CIS), and the Center for Epidemiological Studies Depression Scale (CES-D). Changes over time (T1-T2-T3) on group level and participant level were assessed.

RESULTS

Of the 65 patients, 18 (27.7%) were deceased, 3 (4.6%) experienced tumour progression to WHO III, 7 (10.8%) declined, and 3 (4.6%) could not be contacted. Thirty-four patients (52.3%) participated. Of these, 2 had missing HRQOL data, with 32 patients included in analysis. Survivors were M=52.0 (sd=11.3) years old and diagnosed M=26.2 (sd=3.7, range 19–35) years prior. On group level, a statistically significant (but not clinically relevant) improvement in mental health (p=0.049), and a clinically relevant (but not statistically significant) decline in emotional role functioning was found. No other group-level changes over time in HRQOL were found. Minimal detectable change in HRQOL scale scores over time was observed in individual participants (28.1% only improvement; 25.0% only decline; 21.9% both improvement and decline) with 25.0% remaining completely stable. At T3, 25.0% of survivors scored above the cut-off for high risk of clinical depression (≥16 CES-D), and 53.1% of survivors classed as severely fatigued (≥35 CIS).

CONCLUSION

In this cohort of LGG survivors, assessed decades after diagnosis and treatment, HRQOL does not appear to be greatly impacted during survivorship. However, depressive symptoms and fatigue remain relatively common. Findings can help inform patients, their families, and clinicians and can serve as a benchmark for treatment trials evaluating interventions that can have very long-term effects.

Solitary median maxillary central incisor and congenital nasal pyriform aperture stenosis combined with asymmetric crying facies and postaxial lower limb reduction defects: a unique combination of features

We report a boy with asymmetric crying facies and bilateral absence of the 5th ray of the feet. In addition, craniofacial computed tomography showed a solitary median maxillary central incisor in combination with a narrow apertura piriformis. To our knowledge this intriguing combination of congenital abnormalities has not been described before.