INNV-17. NEXT GENERATION SEQUENCING IMPACTS OUTCOMES IN RECURRENT PRIMARY GLIOBLASTOMA: A SINGLE-CENTER RETROSPECTIVE ANALYSIS

BACKGROUND

GBM is driven by various genomic alterations. Next generation sequencing (NGS) may reveal targetable alterations. The goal of this study was to describe how NGS can inform targeted therapy (TT) selection.

METHODS

The medical records of patients (pts) with GBM from 2017–2019 were reviewed. Pts with actionable mutations were included in the analysis. At first progression (PD1), two cohorts of pts were defined: cohort A received TT, while cohort B received physician’s choice chemotherapy (PCC). Regression analyses were used to determine OS and PFS between cohorts. A stratified cox model was utilized to assess the effect of TT, where KPS level (low vs high) was utilized as a stratification factor. A heat map was generated describing the landscape of mutations. Disease response in cohort A was graded per RANO criteria.

RESULTS

There were 38 GBM pts with actionable alterations. Cohort A had 15 (39%) pts and cohort B had 23 (61%) pts. Of the 26 common alterations, 11 (42%) were deemed actionable. Pts with higher KPS were more likely to receive TT. Pts with a KPS ≥ 70 had a longer PFS while on TT. Although not well powered, pts in cohort A had a longer median OS relative to cohort B (HR 0.37 CI 0.10–1.38). The objective response rate (ORR) was 93%, with afatinib and cabozantinib resulting in complete response, one pt had progressive disease while on TT.

CONCLUSION

NGS for recurrent GBM yields a high rate of actionable alterations. Pts that go on TT are often younger and with higher KPS. This likely plays into their improved survival; however, it is notable that the high ORR reflects the value of NGS in deciding on TT to match alterations that are likely to respond. In conclusion, patient selection and availability of NGS impacts outcomes in recurrent GBM.

The diagnosis and management of primary and iatrogenic soft tissue sarcomas of the sella

PURPOSE

Soft tissue sarcoma (STS) of the sella is exceptionally rare. We conducted a case series, literature review, and nationwide analysis of primary and iatrogenic (radiation-associated) STS of the sella to define the clinical course of this entity.

METHODS

This study employed a multi-institutional retrospective case review, literature review, and nationwide analysis using the National Cancer Database (NCDB).

RESULTS

We report five patients who were diagnosed at three institutions with malignant STS of the sella. All patients presented with symptoms related to mass effect in the sellar region. All tumors extended to the suprasellar space, with the majority displaying extension into the cavernous sinus. All patients underwent an operation via a transsphenoidal approach with a goal of maximal safe tumor resection in four patients and biopsy for 1 patient. Histopathologic evaluation demonstrated STS in all patients. Post-operative adjuvant radiotherapy and chemotherapy were given to 2 and 1 out of 4 patients with known post-operative clinical course, respectively. The 1-year and 5-year overall survival rates were 100% (5/5) and 25% (1/4). Twenty-two additional reports of primary, non-iatrogenic STS of the sella were identified in the literature. Including the three cases from our series, treatment included resection in all cases, and adjuvant radiotherapy and chemotherapy were utilized in 50% (12/24) and 17% (4/24) of cases, respectively. The national prevalence of malignant STS is estimated to be 0.01% among all pituitary and sellar tumors within the NCDB.

CONCLUSIONS

We report the prevalence and survival rates of STS of the sella. Multimodal therapy, including maximal safe resection, chemotherapy, and radiotherapy are necessary to optimize outcomes for this uncommon pathology.

1-Year Mortality and Surgery Incidence in Older US Adults with Cervical Spine Fracture

BACKGROUND

Traumatic cervical spinal cord injuries (SCIs) can be lethal and are especially dangerous for older adults. Falls from standing and risk factors for a cervical fracture and spinal cord injury increase with age. This study estimates the 1-year mortality for patients with a cervical fracture and resultant SCI and compares the mortality rate with that from an isolated cervical fracture.

METHODS

We performed a retrospective cohort study of U.S. Medicare patients older than 65 years of age. International Classification of Diseases (ICD)-9 codes were used to identify patients with a cervical fracture without SCI and patients with a cervical fracture with SCI between 2007 and 2014. Our primary outcome was 1-year mortality cumulative incidence rate; our secondary outcome was the cumulative incidence rate of surgical intervention. Propensity weighted analysis was performed to balance covariates between the groups.

RESULTS

The SCI cohort had a 1-year mortality of 36.5%, compared with 31.1% in patients with an isolated cervical fracture (risk difference 5.4% (2.9%-7.9%)). Patients with an SCI were also more likely to undergo surgical intervention compared with those without a SCI (23.1% and 10.3%, respectively; risk difference 12.8% (10.8%-14.9%)).

CONCLUSIONS

Using well-adjusted population-level data in older adults, this study estimates the 1-year mortality after SCI in older adults to be 36.5%. The mortality after a cervical fracture with SCI was 5 percentage points higher than in patients without SCI, and this difference is smaller than one might expect, likely representing the frailty of this population and unmeasured covariates.

OR23-03 Post-Operative Day One Morning Cortisol Value as a Biomarker to Predict the Recurrence of Cushing Disease

Tumor removal by transsphenoidal surgery (TSS) is the first line treatment for Cushing disease (CD). However, recurrence is relatively common. A one week post-operative (post-op) nadir cortisol has been used as a biomarker to predict recurrence1. We identified 299 CD patients from our longitudinal multidisciplinary clinic or our institutional RPDR search tool who met biochemical diagnostic criteria1 and had undergone TSS between May 2008 and May 2018, to evaluate post-op cortisol levels as biomarkers to predict long-term remission and to characterize clinical features of Cushing syndrome. Predictors of recurrence were identified with logistic regression, using recurrence as the dependent variable, and a Kaplan-Meier survival curve analysis was performed to compare long-term remission after TSS among the 202 patients who reached initial remission and had at least 1 year of follow-up. The post-op day 1 morning (AM) cortisol had significant association with CD recurrence (OR=1.025, 95%CI:1.002-1.048, p=0.032). The time to recurrence was significantly longer in patients with post-op day 1 AM cortisol <5 μg/dL. In contrast, one week post-op nadir cortisol (OR=1.081, 95%CI: 0.989-1.181, p=0.086), urinary free cortisol (OR=1.032,95%CI: 0.994-1.07, p=0.098), or late night salivary cortisol (OR=1.383, 95%CI:0.841-2.274, p=0.201) had no significant correlation with recurrence. There were no significant differences in time to recurrence for post-op day 2 AM cortisol <5 μg/dL. Among patients who developed post-op adrenal insufficiency, recurrence was significantly lower if glucocorticoid replacement continued for more than one year. In addition, tumor proliferative index (MIB-1) had a significant correlation with recurrence (OR=1.287, 95%CI:1.106-1.498, p=0.001). The most common symptoms and signs of initial presentation of CD were weight gain (91.6%), central obesity (79.6%), menstrual disorders (77.9%), round face (65.9%), hypertension (63.2%), mood disorders (60.2%), dorsocervical fat deposition (59.9%), supraclavicular fat deposition (59.9%), osteoporosis (58.9%), fatigue (58.2%), bruising (55.9%) and facial hirsutism (54.2%). Most of the best discriminating CD features did not have high sensitivity, such as purple striae (31.4%), facial plethora (33.4%) and proximal muscle weakness (30.8%). Our data show that post-op day one morning cortisol level above 5 μg/dL had significant association with recurrence. In contrast, the one week post-op nadir cortisol level had no significant value to predict recurrence. Our data also suggest that nonspecific symptoms and signs of CD are more common than stereotypical signs. Reference: Nieman LK, et al. Treatment of Cushing’s Syndrome: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 2015; 100:2807-2831

SAT-LB57 The Spectrum of Genomic and Transcriptomic Alterations in ACTH-Producing and ACTH-Silent Corticotroph Adenomas

Corticotroph adenomas (CA) are rare pituitary tumors that impose several challenges in clinical management - CA are difficult to diagnose, often recur, and are associated with high morbidity and mortality. CA are characteristically Tpit-positive and PIT1-negative and comprise ACTH-producing (Cushing’s disease (CD)) and ACTH-silent (AS) classes. The molecular programs contributing to disease pathogenesis in CA are still poorly characterized, largely restricted to the identification of somatic mutations in USP8 in 40-60% of CD adenomas. To more fully characterize the mutational and transcriptional landscape driving both classes of CA, we performed whole-exome sequencing and RNA-seq in 19 CD and 16 AS adenomas. We identified USP8 mutations in 53% of CD (10/19) and 6% of AS (1/16) samples. Strikingly, in 19% of AS tumors (3/16), all exhibiting an unusually aggressive disease course, including two cases with brain metastases, we identified recurrent somatic pathogenic mutations in TP53 and novel loss-of-function mutations in telomere maintenance genes DAXX and ATRX. Furthermore, while all tumors with USP8 mutations (regardless of CD/AS status) exhibited no chromosomal abnormalities as measured by copy-number variation (CNV) and loss of heterozygosity (LOH) analysis, 33% of CD (4/12, including 1 tumor with a DAXX mutation) and 36% of AS (4/11, including all DAXX/ATRX-mutated cases) samples exhibited profound chromosomal instability, characterized by hyperdiploidy, widespread whole-chromosome LOH events, and arm-level breakpoints. Using transcriptome analysis (n=22), we identified three classes of tumors (C1-C3), reflecting these distinct somatic alteration profiles. C1 tumors (n=6) are characterized by chromosomal stability, includes exclusively USP8-mutated CD, and exhibits upregulation of genes involved in metabolic processes and protein acetylation. C2 tumors (n=10) are comprised exclusively of AS (including all TP53- and/or DAXX/ATRX-mutated cases), are characterized by chromosomal instability, and exhibits concordant upregulation of cell cycle programs. Finally, C3 (n=6) contains a mixture of AS and CD cases (including CD without mutations in USP8) and features an expression profile that partly overlap with C1 tumors, but also exhibit higher expression of inflammatory genes. Taken together, our data suggest that CD and AS are distinct molecular subtypes of CA, highlighting the dominant role of USP8 mutations in driving a unique transcriptional program and illustrate for the first time that unlike most cases of CD, AS cases are characterized by profound genomic instability and cell cycle activation, features associated with a more aggressive disease course.

INNV-43. IMPROVING POST OPERATIVE FOLLOW-UP AND TIME TO ADJUVANT TREATMENT FOR HIGH GRADE GLIOMA

BACKGROUND

High grade glioma patients are prone to lapses in treatment due to the complexities related to coordination of care, the timing of adjuvant treatment, and insurance barriers. The purpose of this study was to determine the impact of an institutional multidisciplinary protocol on transitions of care after surgery for high grade gliomas between 2015 and 2018.

METHODS

A retrospective cohort study was conducted using CPT codes for enrolled glioma patients between 2015–2018 with unplanned surgery. Historical controls were compared to the intervention group which began enrollment in November 2016. We used time-to-event analysis to compare time to neuro-oncology follow up and time to adjuvant treatment (radiation and/or chemotherapy). The effect of discharge disposition and insurance status was also assessed. The study incorporated an ad hoc analysis of survival outcomes.

RESULTS

The intervention and control groups had similar baseline characteristics. The intervention was associated with more patients following up with neuro-oncology within 2 weeks (51.1% in intervention group compared to 30.0% in control group), more patients starting radiation within 30 days (43.6% and 25.0%, respectively) and more patients starting chemotherapy within 30 days (59.0% and 35.0%, respectively). Time-to-event analysis revealed that the intervention trended toward earlier initiation of chemotherapy (p=0.076). Only 16.7% of patients discharge to a skilled nursing facility were able to initiate chemotherapy at the 30-day mark. Time-to-event analysis revealed that insurance status was significantly associated with initiating chemotherapy at the 30-day mark (p=0.023). Survival analysis is planned and will be reported in a future manuscript.

CONCLUSION

A multidisciplinary approach to capturing patients after surgery decreases time to follow up with neuro-oncology and initiation of adjuvant treatment. Timely follow up is associated with insurance status, discharge disposition, and multidisciplinary discussions between the treatment team and ancillary staff. Survival outcomes are being assessed and will be reported.

Contralateral Approach for Minimally Invasive Treatment of Upper Lumbar Intervertebral Disc Herniation: Technical Note and Case Series

BACKGROUND

Upper lumbar disc herniations comprise only 1%-2% of all lumbar disc herniations. Patients exhibit nonspecific signs and symptoms in comparison to predictable radiculopathies, as seen in lower lumbar disc herniations. The unique anatomic characteristics of the upper lumbar spine present several challenges for safe and effective surgical treatment of disc herniations. The authors review the anatomy of the upper lumbar spine, describe a novel approach to upper lumbar disc herniations, and present 3 cases with a focus on clinical outcome and technical pearls.

METHODS

Conventional techniques for upper lumbar discectomy require a near complete facetectomy and pars interarticularis resection for adequate bony exposure, possibly leading to spinal destabilization. A tubular retractor system was used to approach upper lumbar disc herniation using a contralateral minimally invasive technique, while completely preserving the facet complex and pars interarticularis.

RESULTS

We report 3 cases of minimally invasive discectomy from a contralateral approach. The patients experienced complete resolution of presenting symptoms, and the facet complexes were preserved. All cases were free of complications.

CONCLUSION

A contralateral approach to perform a minimally invasive discectomy for paracentral and central upper LDH is a safe, efficient, and effective technique. The approach that we describe in this study preserves the facet complex and may prevent future spinal instability.