Virtual multi-institutional tumor board: a strategy for personalized diagnoses and management of rare CNS tumors

PURPOSE

Multidisciplinary tumor boards (MTBs) integrate clinical, molecular, and radiological information and facilitate coordination of neuro-oncology care. During the COVID-19 pandemic, our MTB transitioned to a virtual and multi-institutional format. We hypothesized that this expansion would allow expert review of challenging neuro-oncology cases and contribute to the care of patients with limited access to specialized centers.

METHODS

We retrospectively reviewed records from virtual MTBs held between 04/2020-03/2021. Data collected included measures of potential clinical impact, including referrals to observational or therapeutic studies, referrals for specialized neuropathology analysis, and whether molecular findings led to a change in diagnosis and/or guided management suggestions.

RESULTS

During 25 meetings, 32 presenters discussed 44 cases. Approximately half (n = 20; 48%) involved a rare central nervous system (CNS) tumor. In 21% (n = 9) the diagnosis was changed or refined based on molecular profiling obtained at the NIH and in 36% (n = 15) molecular findings guided management. Clinical trial suggestions were offered to 31% (n = 13), enrollment in the observational NCI Natural History Study to 21% (n = 9), neuropathology review and molecular testing at the NIH to 17% (n = 7), and all received management suggestions.

CONCLUSION

Virtual multi-institutional MTBs enable remote expert review of CNS tumors. We propose them as a strategy to facilitate expert opinions from specialized centers, especially for rare CNS tumors, helping mitigate geographic barriers to patient care and serving as a pre-screening tool for studies. Advanced molecular testing is key to obtaining a precise diagnosis, discovering potentially actionable targets, and guiding management.

Federated learning enables big data for rare cancer boundary detection

Although machine learning (ML) has shown promise across disciplines, out-of-sample generalizability is concerning. This is currently addressed by sharing multi-site data, but such centralization is challenging/infeasible to scale due to various limitations. Federated ML (FL) provides an alternative paradigm for accurate and generalizable ML, by only sharing numerical model updates. Here we present the largest FL study to-date, involving data from 71 sites across 6 continents, to generate an automatic tumor boundary detector for the rare disease of glioblastoma, reporting the largest such dataset in the literature (n = 6, 314). We demonstrate a 33% delineation improvement for the surgically targetable tumor, and 23% for the complete tumor extent, over a publicly trained model. We anticipate our study to: 1) enable more healthcare studies informed by large diverse data, ensuring meaningful results for rare diseases and underrepresented populations, 2) facilitate further analyses for glioblastoma by releasing our consensus model, and 3) demonstrate the FL effectiveness at such scale and task-complexity as a paradigm shift for multi-site collaborations, alleviating the need for data-sharing.

EPID-03. PATHOGENIC GERMLINE MUTATIONS IN GLIOMA PATIENTS

BACKGROUND

No consensus germline testing guidelines currently exist for glioma patients. Hence such testing is not routinely performed. The prevalence and type of germline pathogenic variants in these brain tumors remains unknown. DESIGN/

METHODS

A retrospective review of patients treated at Baylor College of Medicine with paired tumor/normal sequencing using the Tempus xT tumor/normal matched approach from August 2018- April 2022 was performed. Corresponding clinical data was collected for these patients.

RESULTS

We identified 152 glioma patients of which 15 (9.8%) had pathogenic germline variants. Pathogenic germline variants were seen in 11/84 (13.1%) of Glioblastoma, IDH wildtype, 3/42 (7.1%) of Astrocytoma, IDH mutant and 1/26 (3.8%) of Oligodendroglioma, IDH mutant and 1p/19q co-deleted patients. Pathogenic variants in BRCA2, MUTYH and CHEK2 were seen more commonly (3/15 or 20% each). BRCA1 variants were seen in 2/15 (13%) patients, with variants in NF1, ATM, MSH2, and MSH3 occurring in one patient (7%) each. Second hit somatic variants were seen in 3/15 patients (20%). A second somatic hit was seen in NF1, MUTYH and MSH2 in one patient (7%) each. Referral to genetics was performed in 6/15 (40%) patients with pathogenic germline variants. Median overall survival was 1.6 years for glioblastoma, IDH wildtype patients with a pathogenic germline variant compared to 1.79 years for glioblastoma, IDH wildtype patients without it (p = 0.67).

CONCLUSIONS

Although not routinely performed in glioma patients, pathogenic germline variants occurred in ~10% of our patients. Only 40% of these patients were referred to genetics. These findings suggest a possible overlooked opportunity for determination of hereditary cancer syndromes with impact on surveillance as well as potential broader treatment options. Further research to confirm the occurrence and types of pathogenic germline variants in patients with IDH wildtype compared to IDH mutant tumors is necessary.

Racial and Socioeconomic Disparities in Patients With Meningioma: A Retrospective Cohort Study

BACKGROUND

Meningiomas are the most common intracranial neoplasms. Although genomic analysis has helped elucidate differences in survival, there is evidence that racial disparities may influence outcomes. African Americans have a higher incidence of meningiomas and poorer survival outcomes. The etiology of these disparities remains unclear, but may include a combination of pathophysiology and other factors.

OBJECTIVE

To determine factors that contribute to different clinical outcomes in racial populations.

METHODS

We retrospectively reviewed 305 patients who underwent resection for meningiomas at a single tertiary care facility. We used descriptive statistics and univariate, multivariable, and Kaplan-Meier analyses to study clinical, radiographical, and histopathological differences.

RESULTS

Minority patients were more likely to present through the emergency department than an outpatient clinic (P < .0001). They were more likely to present with more advanced clinical symptoms with lower Karnofsky Performance scores, more frequently had peritumoral edema (P = .0031), and experienced longer postoperative stays in the hospital (P = .0053), and African-American patients had higher hospitalization costs (P = .046) and were more likely to be publicly insured. Extent of resection was an independent predictor of recurrence freedom (P = .039). Presentation in clinic setting trended toward an association with recurrence-free survival (P = .055). We observed no significant difference in gross total resection rates, postoperative recurrence, or recurrence-free survival.

CONCLUSION

Minority patients are more likely to present with severe symptoms, require longer perioperative hospitalization, and generate higher hospitalization costs. This may be due to socioeconomic factors that affect access to health care. Targeting barriers to access, especially to subspecialty care, may facilitate more appropriate and timely diagnosis, thereby improving patient care and outcomes.

INNV-27. AN INNOVATIVE VIRTUAL MULTI-INSTITUTIONAL, MULTIDISCIPLINARY NEURO-ONCOLOGY TUMOR BOARD: THE NIH-NOB EXPERIENCE DURING THE COVID-19 PANDEMIC

BACKGROUND

The American Academy of Neurology Institute and Society for Neuro-Oncology recommend multidisciplinary tumor board (MTB) meetings as a quality metric in neuro-oncology. With the COVID-19 pandemic resulting in travel restrictions, we expanded our existing MTB by transitioning to a virtual format that maintained our commitment to providing consultation for primary CNS tumor cases. This transition permitted participation by neuro-oncology teams from over 30 Brain Tumor Trials Collaborative (BTTC)/National Cancer Institute-Comprehensive Oncology Network Evaluating Rare CNS Tumors (NCI-CONNECT) centers across the United States. Here, we describe results from opening our MTB remotely to these teams.

METHODS

We retrospectively reviewed records from remote MTB meetings held between April 2020 and March 2021. To gauge the impact of our MTB on clinical management, we administered a brief survey querying BTTC members.

RESULTS

Twenty-eight providers presented 41 cases during 24 virtual MTB meetings (range: 1-4 cases per meeting). Two cases (5%) were presented only for educational value. Approximately half (54%) of the cases discussed dealt with diagnosis/management of an NCI-CONNECT rare CNS tumor. During MTB discussions of the 39 cases seeking diagnosis/management recommendations, 32% received clinical trial recommendations, 10% were suggested to enroll in the NCI Neuro-Oncology Branch (NOB) Natural History Study (NCT02851706), 17% received a recommendation to obtain central neuropathology review, and 100% received recommendations for further disease management. Most BTTC survey respondents (83%) found these recommendations impactful in the management/treatment of their presented case or generally useful/informative for their clinical practice.

CONCLUSION

We describe the feasibility and utility of an innovative virtual multi-institutional MTB. These novel remote meetings allowed for discussion of complex neuro-oncology cases and recommendations from experts, particularly important for those with rare CNS tumors. Our study’s findings during the COVID-19 pandemic of the value of providing remote access to MTBs should apply post-pandemic.

Height in adolescence as a risk factor for glioma subtypes: a nationwide retrospective cohort study of 2.2 million subjects

BACKGROUND

Gliomas manifest in a variety of histological phenotypes with varying aggressiveness. The etiology of glioma remains largely unknown. Taller stature in adulthood has been linked with glioma risk. The aim of this study was to discern whether this association can be detected in adolescence.

METHODS

The cohort included 2 223 168 adolescents between the ages of 16 and 19 years. Anthropometric measurements were collected at baseline. Incident cases of glioma were extracted from the Israel National Cancer Registry over a follow-up period spanning 47 635 745 person-years. Cox proportional hazard models were used to estimate the hazard ratio (HR) for glioma and glioma subtypes according to height, body mass index (BMI), and sex.

RESULTS

A total of 1195 patients were diagnosed with glioma during the study period. Mean (SD) age at diagnosis was 38.1 (11.7) years. Taller adolescent height (per 10-cm increase) was positively associated with the risk for glioma of any type (HR: 1.15; P = .002). The association was retained in subgroup analyses for low-grade glioma (HR: 1.17; P = .031), high-grade glioma (HR: 1.15; P = .025), oligodendroglioma (HR: 1.31; P = .015), astrocytoma (HR: 1.12; P = .049), and a category of presumed IDH-mutated glioma (HR: 1.17; P = .013). There was a trend toward a positive association between height and glioblastoma, however this had borderline statistical significance (HR: 1.15; P = .07). After stratification of the cohort by sex, height remained a risk factor for men but not for women.

CONCLUSIONS

The previously established association between taller stature in adulthood and glioma risk can be traced back to adolescence. The magnitude of association differs by glioma subtype.

Window-of-opportunity clinical trial of pembrolizumab in patients with recurrent glioblastoma reveals predominance of immune-suppressive macrophages

BACKGROUND

We sought to ascertain the immune effector function of pembrolizumab within the glioblastoma (GBM) microenvironment during the therapeutic window.

METHODS

In an open-label, single-center, single-arm phase II "window-of-opportunity" trial in 15 patients with recurrent (operable) GBM receiving up to 2 pembrolizumab doses before surgery and every 3 weeks afterward until disease progression or unacceptable toxicities occurred, immune responses were evaluated within the tumor.

RESULTS

No treatment-related deaths occurred. Overall median follow-up time was 50 months. Of 14 patients monitored, 10 had progressive disease, 3 had a partial response, and 1 had stable disease. Median progression-free survival (PFS) was 4.5 months (95% CI: 2.27, 6.83), and the 6-month PFS rate was 40%. Median overall survival (OS) was 20 months, with an estimated 1-year OS rate of 63%. GBM patients' recurrent tumors contained few T cells that demonstrated a paucity of immune activation markers, but the tumor microenvironment was markedly enriched for CD68+ macrophages.

CONCLUSIONS

Immune analyses indicated that pembrolizumab anti-programmed cell death 1 (PD-1) monotherapy alone can't induce effector immunologic response in most GBM patients, probably owing to a scarcity of T cells within the tumor microenvironment and a CD68+ macrophage preponderance.

The concurrence of multiple sclerosis and glioblastoma

INTRODUCTION

Glioblastoma rarely coincides with multiple sclerosis. Although registries have reported a higher proportion of brain tumors-most of which are glial-these events appear to be underreported. The relative contribution of JC virus (an oncogenic virus) and disease modifying therapies that may facilitate JC virus neurotropism and tumor-specific immune evasion remain unknown.

CASE REPORT

We present the case of a 64-year-old woman who developed a primary glioblastoma eight years after diagnosis of multiple sclerosis while on dimethyl fumarate.

CONCLUSION

Systematic reporting may help answer whether JC virus seropositivity and certain disease modifying therapies confer higher risk for glioblastoma in patients with multiple sclerosis.

Intracranial Solitary Fibrous Tumor of the Skull Base: 2 Cases and Systematic Review of the Literature

BACKGROUND

Intracranial solitary fibrous tumors (ISFTs) are rare neoplasms of mesenchymal origin that originate from the meninges. ISFTs of the skull base can be challenging to treat, as resection can be complicated by skull base anatomy. We present 2 cases of ISFT, the first manifesting with compressive cranial neuropathy from Meckel cave involvement and the second a posterior fossa lesion causing symptomatic hydrocephalus.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed database was queried with title/abstract keywords "intracranial," "solitary fibrous tumor," "hemangiopericytoma," "SFT," and "HPC." Search results were reviewed to exclude cases not involving the skull base. References from all selected articles were reviewed for potential additional cases. Patient demographic and clinical data from 58 identified skull base cases were collected for qualitative synthesis.

RESULTS

Visual disturbances were the most common presenting symptom (30 cases, 52%) followed by headache (22 cases, 38%). The most common site of involvement was the sellar/parasellar region (18 cases, 31%) followed by middle fossa/temporal bone (14 cases, 24%). Resection was performed in 55 cases; gross total resection was reported in 26 cases (45%) and subtotal resection was reported in 21 cases (36%). Tumor recurrence was documented in 15 cases (26%) with median and mean follow-up periods of 16 and 29.9 months, respectively.

CONCLUSIONS

We discuss presentation, imaging, histopathology, and management considerations for ISFTs while highlighting the potentially complex nature of skull base lesions and need for multidisciplinary approach to treatment.

Multicentric non-enhancing lesions in glioblastoma: A retrospective study

Glioblastoma (GBM) typically presents as a single lesion. Multicentric GBM are defined as well separated lesions on MRI (enhancing and non-enhancing). Multicentric GBM with non-enhancing lesions (MNE-GBM) are rarely described in literature. We aimed at describing the radiologic characteristics, treatment, and clinical course of those patients. The institutional neuropathological database was searched for GBM patients diagnosed between 1/1/2015 and 31/05/2018. All pre-operative MRI brain scans were reviewed to identify patients with MNE-GBM. Electronic medical records and follow-up MRI scans were reviewed to assess progression-free survival (PFS) and overall survival (OS). Out of 149 adult patients with newly diagnosed GBM, 12 met the inclusion criteria of MNE-GBM, all of them presented at least one enhancing lesion. Median follow-up for the MNE-GBM patients was 16.1 months. At last follow-up, all patients had recurrence (median PFS 7.6 months) and eleven patients had deceased. Median OS was 16.2 months (95% CI, 4.1-27.5). Eleven patients received radiotherapy concomitant with temozolomide as initial treatment. Radiation field included all the disease foci (enhancing and non-enhancing lesions) in 8 patients, five of them progressed within the non-enhancing lesion. Three patients did not receive radiation for the entire non-enhancing lesions, and two of them progressed within the non-irradiated areas. In conclusion, MNE-GBM is not rare, and has high risk of aggressive progression within the separate non-enhancing lesion.

BIOM-01. TYROSINE KINASE INHIBITORS AS A TREATMENT OF SYMPTOMATIC CNS METASTASES IN ONCOGENE-DRIVEN NSCLC

BACKGROUND

Central nervous system (CNS) metastases occur frequently in oncogene-driven non-small cell lung cancer (NSCLC). Standard treatment (i.e surgery, whole brain radiation therapy or stereotactic radiosurgery) approaches can potentially delay systemic treatment and/or result in neurocognitive impairment. Recently, next generation tyrosine kinase inhibitors (TKIs) have demonstrated a remarkable intracranial activity. However, most clinical trials did not enroll patients with neurological symptoms. Our study aims to assess the CNS activity of targeted therapy in this patient population.

METHOD

We present a case series of nine NSCLC patients with either EGFR mutation of ALK rearrangement and symptomatic CNS metastases that were treated with TKIs, without radiation therapy or surgery. Clinicopathological characteristics, treatment and outcome were analyzed.

RESULTS

Most patients presented with symptomatic CNS metastases at time of metastatic disease presentation (6/9 patients). Additionally, the majority of patients had leptomingeal disease (6/9 patients) and multiple parenchymal metastases. Patients presented with a variety of CNS symptoms with the most common being nausea, vomiting, headache and confusion. Five patients were treated with Osimertinib. One patient with ALK rearrangement was treated with Lorlatinib. The remaining 3 patients received either Gefitinib or Afatinib. Most patients (6/9 patients) responded rapidly both clinically and radiographically to the targeted treatment, with a marked correlation between systemic and intracranial radiographic response.

CONCLUSION

Upfront use of next generation TKIs in patients with oncogene-driver NSCLC with symptomatic CNS metastases is associated with reasonable intracranial activity and represents a valuable treatment option.

NCMP-10. IDH MUTATION STATUS AND THE DEVELOPMENT OF VENOUS THROMBOEMBOLISM IN ASTROCYTOMA PATIENTS

OBJECTIVE

Examine whether the status of the isocitrate dehydrogenase (IDH) gene is a risk factor for the development of venous thromboembolism (VTE) in astrocytoma patients.

BACKGROUND

The risk of venous thromboembolism (VTE) is high for patients with gliomas (10–30%). Unfortunately, biomarkers and predictive models for development of a VTE in brain cancer have not been validated. Prior research has suggested that IDH wildtype gliomas are at higher risk for development of VTE compared to IDH mutant tumors.

DESIGN/METHODS

We conducted a retrospective chart review of glioma patients enrolled in the PROACTIVE (Prospective Assessment of Correlative Biomarker) study at MD Anderson Cancer Center (MDACC). We obtained demographics, date of tumor diagnosis, initial pathology, IDH status (mutated or wildtype), extent of initial resection, KPS at time of initial resection, history of VTE, development of VTE, type of VTE (PE/DVT), KPS at time of VTE, treatment for VTE, bleeding complications, glioma treatments, date of last follow up and/or death.

RESULTS

We identified 282 astrocytoma patients consisting of 49 IDH mutant and 233 IDH wildtype astrocytomas. Glioblastoma was the histopathologic diagnosis in 30 (61.2%) of the IDH mutated astrocytomas compared to 227(97.4%) of the IDH wild type astrocytomas. VTE was identified in 52 (18.4%) of patients. VTE was diagnosed in 7 (14.3%) of the IDH mutated astrocytomas compared to 45 (19.3%) of the IDH wild type astrocytomas (p = 0.4094). Median time to VTE from diagnosis was 2.71 months. Median time to VTE from diagnosis was 2.6 months for IDH mutated astrocytomas compared to 3.06 months for the IDH wild type astrocytomas (p =0.8663).

CONCLUSIONS

IDH gene status did not appear as a significant risk factor for the development of venous thromboembolism (VTE) in our cohort of astrocytoma patients. Further research into potential biomarkers for VTE may be warranted.

Paraneoplastic syndromes in small cell lung cancer

Paraneoplastic syndromes can commonly occur due to lung cancer, especially small cell lung cancer. Frequently paraneoplastic syndromes can precede the diagnosis of the neoplasm or present with limited stage disease. However, these syndromes can also occur at the time of recurrence or metastasis of disease. This review focuses on the epidemiology, pathogenesis, clinical features, and current management of the most common paraneoplastic syndromes encountered in patients with small cell lung cancer. Manifestations of paraneoplastic syndromes in small cell lung cancer include endocrine syndromes with secretion of excess hormones, and neurologic syndromes due to the production of antibodies causing an autoimmune condition. Recent advances have allowed for greater understanding of these syndromes and for the development of improved diagnostic as well as therapeutic tools. Awareness of paraneoplastic syndromes in small cell lung cancer can lead to an earlier diagnosis and recognition of both the condition and in some cases the disease potentially improving the overall survival and prognosis for patients. Further research examining effective methods to improve recovery from neurologic deficits in patients with a paraneoplastic neurologic illness is warranted.

Tyrosine Kinase Inhibitors as a Treatment of Symptomatic CNS Metastases in Oncogene-Driven NSCLC

Central nervous system (CNS) metastases occur frequently in oncogene-driven non-small cell lung cancer (NSCLC). Standard treatment approaches can potentially delay systemic treatment (surgical intervention) or result in neurocognitive impairment (radiotherapy). Recently, next-generation tyrosine kinase inhibitors (TKIs) have demonstrated remarkable intracranial activity. However, most clinical trials did not enroll patients suffering neurological symptoms. Our study aimed to assess the CNS activity of targeted therapies in this patient population. We present a case series of nine NSCLC patients with either EGFR mutation or ALK rearrangement and symptomatic CNS metastases that were treated with TKIs. Clinicopathological characteristics, treatment, and outcomes were analyzed. Most patients presented with symptomatic CNS metastases at time of metastatic disease presentation (6/9). Additionally, the majority of patients had leptomeningeal disease (6/9) and multiple parenchymal metastases. Patients presented with a variety of CNS symptoms with the most common being nausea, vomiting, headache, and confusion. Most patients (6/9) responded rapidly both clinically and radiographically to the targeted treatment, with a marked correlation between systemic and intracranial radiographic response. In conclusion, upfront use of next-generation TKIs in patients with oncogene-driven NSCLC with symptomatic CNS metastases is associated with reasonable intracranial activity and represents a valuable treatment option.

Height as a risk factor in meningioma: a study of 2 million Israeli adolescents

BACKGROUND

Meningiomas are the most common primary central nervous system tumors. Potential risk factors include obesity, height, history of allergy/atopy, and autoimmune diseases, but findings are conflicting. This study sought to assess the role of the different risk factors in the development of meningioma in adolescents/young adults.

METHODS

The cohort included 2,035,915 Jewish men and women who had undergone compulsory physical examination between 1967 and 2011, at age 16 to 19 years, prior to and independent of actual military enlistment. To determine the incidence of meningioma, the military database was matched with the Israel National Cancer Registry. Cox proportional hazard models were used to estimate the hazard ratios for meningioma according to sex, body mass index (BMI), height, and history of allergic or autoimmune disease.

RESULTS

A total of 480 subjects (328 females) were diagnosed with meningioma during a follow-up of 40,304,078 person-years. Median age at diagnosis was 42.1 ± 9.4 years (range 17.4-62.6). On univariate analysis, female sex (p < 0.01) and height (p < 0.01) were associated with risk of meningioma. When the data were stratified by sex, height remained a significant factor only in men. Spline analysis of the male subjects showed that a height of 1.62 m was associated with a minimum disease risk and a height of 1.85+ meters, with a significant risk.

CONCLUSIONS

This large population study showed that sex and adolescent height in males (> 1.85 m) were associated with an increased risk of meningioma in adulthood.

Spinal meningioma in a patient with multiple sclerosis

Background:

Multiple sclerosis (MS) is the most common immune-mediated inflammatory demyelinating disease of the central nervous system. Multiple brain and spinal tumors have been linked to MS, but a causal relationship between the two has not been determined. Here, we report a case of spinal meningioma in a patient with MS and review literature discussing the possible connection between these two disease entities.

Case Description:

A 58-year-old female with MS presented with a 1-year history of progressively worsening back pain in conjunction with worsening right upper and lower extremity weakness. The patient was diagnosed with MS 19 months prior and had multiple known demyelinating plaques in her cervical spine. New MRI revealed an intradural extramedullary thoracic tumor with characteristics consistent with meningioma. She underwent T6- T8 laminectomies for tumor resection and pathology confirmed the radiological diagnosis. At 3-month follow- up, the patient reported complete resolution of her back pain and persistence of weakness-related gait issues.

Conclusion:

CNS neoplasms including meningioma should be considered in MS patients presenting with newly onset neurological symptoms not entirely consistent with demyelinating disease. Both disease processes should be addressed with appropriate long-term follow-up.

Pineal parenchymal tumor of intermediate differentiation: a single-institution experience

Background

Pineal parenchymal tumors are exceedingly rare brain tumors responsible for less than 1% of all adult primary intracranial malignancies in the United States. In this study, we describe the clinicopathologic features, management, and outcomes of patients with pineal parenchymal tumor of intermediate differentiation (PPTID).

Methods

We describe a single-center, multidisciplinary team experience in managing PPTID patients over a 15-year period (January 2000 to January 2015) at The University of Texas MD Anderson Cancer Center (MDACC). Pathology was reviewed by the pathology collaborators (A.G. and G.N.F.) and retrospective chart review was performed for treatment and clinical outcomes.

Results

We identified 17 patients (9 male) with diagnosis of PPTID. Median age at diagnosis of PPTID was 37 years (range, 15-57 years). Follow-up ranged from 0.1 to 162.8 months with 6 reported deaths. Most patients presented with headaches and diplopia. Three patients had neuroaxial dissemination at initial diagnosis, and recurrence of tumor was common (7/16) despite treatment.

Conclusions

No clear prognostic factors were identified in this series. Extension of resection showed a trend toward improved survival. PPTID with neuroaxial dissemination benefits from aggressive initial treatment including craniospinal irradiation and adjuvant chemotherapy, whereas localized disease may be treated traditionally with maximum debulking followed by adjuvant radiotherapy alone. Long-term monitoring is recommended for neurotoxicity and/or late recurrence.

Total serum cholesterol by isotope dilution/mass spectrometry: a candidate definitive method

We describe a highly accurate and precise method for determination of total cholesterol in serum by isotope dilution/mass spectrometry. The method was developed for a Study Group of the Committee on Standards of the American Association for Clinical Chemistry, for use in establishing the accuracy of a candidate reference method for total cholesterol, and fulfills their criteria for a definitive method. Cholesterol-d7 is added to serum, with the weight ratio of cholesterol-d7 to total serum cholesterol kept near to 1:1. The esters are hydrolyzed and the cholesterol is separated and converted into the trimethylsilyl ether derivative for measurement by combined gas chromatography/mass spectrometry. The intensity ratio of the molecular ions at m/z 465 and 458 is measured for each sample and for two calibration mixtures, according to a prescribed bracketing protocol. A weight ratio for the sample is obtained by linear interpolation of the ion-intensity ratios, and the total cholesterol is then calculated. The method was applied four times over several weeks to each of five serum pools. Statistical analysis involving consideration of both replication error and variability between weeks gave a coefficient of variation for a single measurement of 0.36%. The absence of interferences in the method was demonstrated by measurements at several other masses.

QOLP-30. CLINICAL PREDICTIVE MODEL FOR THE DEVELOPMENT OF VENOUS THROMBOEMBOLISM IN GLIOBLASTOMA

INTRODUCTION

The risk of venous thromboembolism (VTE) remains high for patients with glioblastoma (GBM) throughout the disease trajectory. Our previous work demonstrated the Khorana scale lacks specificity in this population. We therefore constructed, and attempted to validate a predictive model specific for the development of VTE during adjuvant chemotherapy in glioblastoma patients.

METHODS

A prior study of GBM patients treated at MD Anderson (MDACC) during the years 2005–2011 found from a multivariate analysis that male sex, BMI ≥ 35, KPS ≤ 80, and steroid therapy were significantly associated with the development of VTE. A predictive model from the MDACC cohort was created using these risk factors, and we attempted to validate the model in an independent cohort of GBM patients treated at Henry Ford from 2010–2015.

RESULTS

To develop the model 315 patients from the MDACC cohort were randomly divided into two parts: training (75% of data) used for model building, and validation (25% of data) used for model validation. Using the predictive model, the MDACC validation cohort found 80% sensitivity and 80% specificity. We then validated the model in the Henry Ford cohort of 190 GBM patients of which 50 developed a VTE. In the external validation set, the predictive model was found to have a sensitivity = 78% and specificity = 49.3% (Fisher test p-value = 0.0008).

CONCLUSIONS

Our predictive model for the development of VTE during adjuvant chemotherapy in GBM patients retained high sensitivity in an external data set, however high specificity was lost. While the specificity in our model was higher than in previous studies examining the Khorona scale in GBM patients, further refinement to improve the models reliability to correctly identify people who will not later develop a VTE may be helpful.

HOUT-18. TREATMENT STRATEGIES FOR GLIOBLASTOMA IN OLDER PATIENTS: AGE IS JUST A NUMBER

BACKGROUND

Optimal care for elderly patients with glioblastoma (GBM) remains in question due to their exclusion from and underrepresentation in clinical trials (including EORTC 22981) as well as their historically-poor overall survival.

METHODS

Retrospective chart review was conducted at a single high-volume cancer center for newly-diagnosed elderly (65 years old or older) GBM patients diagnosed from 2011 through 2017.

RESULTS

A total of 158 newly-diagnosed GBM patients aged 65 years and older were identified. 144 patients (91.1%) underwent radiation therapy. One-hundred thirty patient (90.3%) received concurrent temozolomide with radiotherapy. A minority of patients (23%) discontinued temozolomide during concurrent or adjuvant treatment due to side effects or complications of chemotherapy. Sixty-one patients (38.6%) completed concurrent chemoradiation and 6 cycles of adjuvant temodar. The median overall survival (OS) time for our cohort was 18.6 months, with estimated OS rates of 74.8%, 35.9%, and 9.5% at 1, 2, and 5 years, respectively. On multivariable analysis, higher KPS (p=0.002, HR 0.46; 95% CI: 0.63–0.82), completing planned course of radiation (p=0.01, HR 0.29; 95% CI: 0.11–0.75), and completing 6 cycles of adjuvant temozolomide (p=0.01, HR 2.62; 95% CI: 1.67–4.12) were associated with improved OS.

CONCLUSIONS

Our cohort of elderly GBM patients were predominately treated with a standard of care based on EORTC 22981. Despite their age, these patients tolerated treatment well and had a favorable overall survival compared to outcomes reported for patients treated on EORTC 22981. Using age alone as the reason to de-escalate treatment or as an exclusionary criteria in clinical trials should be discouraged.

Alirocumab safety in people with and without diabetes mellitus: pooled data from 14 ODYSSEY trials

AIM

To evaluate the safety of the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor alirocumab according to diabetes mellitus status.

METHODS

Safety data from 14 trials (8-104-week durations) were analysed by treatment (alirocumab or placebo/ezetimibe control) and diabetes status (yes/no, defined by medical history). Adverse event data were assessed using descriptive statistics and Cox models.

RESULTS

Of the 5234 trial participants, 1554 (29.7%) had diabetes. Overall, treatment-emergent adverse events were similar in the alirocumab and control groups, except for more frequent local injection site reactions with alirocumab. Fewer people with diabetes experienced local injection site reactions [alirocumab, 3.5%, control, 2.9%; hazard ratio 1.24 (95% CI 0.68-2.25)] than those without diabetes [alirocumab, 7.5%; control, 4.9%; hazard ratio 1.51 (95% CI 1.13-2.01)]. Those with diabetes reported a greater number of serious adverse events (alirocumab, 19.4%; control, 19.7%) than those without diabetes (alirocumab, 14.5%; control, 13.5%). In people with diabetes, major adverse cardiac events occurred in 2.7% of alirocumab-treated people [control, 3.3%; hazard ratio 0.74 (95% CI 0.41-1.35)]; in those without diabetes, 1.8% of alirocumab-treated people had major adverse cardiac events [control, 1.7%; hazard ratio 0.95 (95% CI 0.56-1.62)]. Overall, no increase in HbA1c or fasting plasma glucose vs control treatment groups was observed, regardless of diabetes status.

CONCLUSION

This pooled analysis across 14 trials demonstrated similar safety for alirocumab vs control treatment, irrespective of diabetes status, except for more frequent local injection site reactions with alirocumab. People with diabetes reported fewer local injection site reactions than those without diabetes.

Neurologic complications of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICPIs) have recently emerged as a novel treatment for cancer. These agents, transforming the field of oncology, are not devoid of toxicity and cause immune-related side effects which can involve any organ including the nervous system. In this study, we present 9 patients (7 men and 2 women) with neurologic complications secondary to ICPI treatment. These included meningoencephalitis, limbic encephalitis, polyradiculitis, cranial polyneuropathy, myasthenic syndrome and myositis. Four patients received dual ICPI therapy comprised of programmed cell death-1 and cytotoxic lymphocyte associated protein-4 blocking antibodies. Median time to onset of neurologic adverse event during immune checkpoint inhibitor treatment was 8 weeks (range 5 days-19 weeks). In all patients ICPIs were stopped and corticosteroids were initiated, resulting in a marked improvement in seven out of nine patients. Two patients, one with myositis and one with myasthenic syndrome, died. In two patients ICPI therapy was resumed after resolution of the neurological adverse event with no additional neurologic complications. This series highlights the very broad spectrum of neurological complications of ICPIs, emphasizes the need for expedited diagnosis and suggests that withholding treatment early, accompanied with steroid therapy, carries the potential of complete resolution of the neurological immune-mediated condition. Thus, a high level of suspicion and rapid initiation of corticosteroids are mandatory to prevent uncontrolled clinical deterioration, which might be fatal.

Follow-up care for survivors of lymphoma who have received curative-intent treatment

OBJECTIVE

This evidence summary set out to assess the available evidence about the follow-up of asymptomatic survivors of lymphoma who have received curative-intent treatment.

METHODS

The medline and embase databases and the Cochrane Database of Systematic Reviews were searched for evidence published between 2000 and August 2015 relating to lymphoma survivorship follow-up. The evidence summary was developed by a Working Group at the request of the Cancer Care Ontario Survivorship and Cancer Imaging programs because of the absence of evidence-based practice documents in Ontario for the follow-up and surveillance of asymptomatic patients with lymphoma in complete remission.

RESULTS

Eleven retrospective studies met the inclusion criteria. The proportion of relapses initially detected by clinical manifestations ranged from 13% to 78%; for relapses initially detected by imaging, the proportion ranged from 8% to 46%. Median time for relapse detection ranged from 8.6 to 19 months for patients initially suspected because of imaging and from 8.6 to 33 months for those initially suspected because of clinical manifestations. Only one study reported significantly earlier relapse detection for patients initially suspected because of clinical manifestations (mean: 4.5 months vs. 6.0 months, p = 0.042). No benefit in terms of overall survival was observed for patients depending on whether their relapse was initially detected because of clinical manifestations or surveillance imaging.

SUMMARY

Findings in the present study support the importance of improving awareness on the part of survivors and clinicians about the symptoms that might be associated with recurrence. The evidence does not support routine imaging for improving outcomes in this patient population.

Wound healing complications in brain tumor patients on Bevacizumab

Bevacizumab (BEV) is commonly used for treating recurrent glioblastoma (GBM), and wound healing is a well-established adverse event. Retrospective analysis of GBM patients with and without wound healing complications while on BEV treatment is reported. 287 patients identified, majority were males (60 %) with median age of 52.5 years. 14 cases identified with wound healing problems, related to either craniotomy (n = 8) or other soft tissue wounds (n = 6). Median duration of BEV treatment to complication was 62 days (range 6-559). Majority received 10 mg/kg (n = 11) and nine (64.3 %) were on corticosteroids, with median daily dose of 6 mg (range 1-16 mg) for median of 473 days before starting BEV. For dehisced craniotomy wounds, median time for starting BEV from last surgery was 29 days (range 27-345). Median time from starting BEV to developing wound complication was 47 days (range 16-173). Seven (87.5 %) had infected wounds requiring antibiotics, hospitalization. Four (50 %) required plastic surgery. BEV stopped and safely resumed in 6 (75 %) patients; median delay was 70 days (range 34-346). Soft tissue wounds included decubitus ulcer, dehisced striae, herpes simplex, trauma to hand and back, and abscess. Median time from starting BEV to wound issues was 72 days (range 6-559). Five (83.3 %) were infected, requiring antibiotics. While three (50 %) required hospitalization, none required plastic surgery. Treatment stopped in five (83.3 %) and restarted in two (median delay 48 days, range 26-69). Wound healing complications are uncommon but associated with significant morbidity. Identifying those at risk and contributing factors warrants further investigation.

Survival outcome of early versus delayed bevacizumab treatment in patients with recurrent glioblastoma

2042

Background: Bevacizumab (BEV) is widely used for treatment of patients with recurrent glioblastoma (GB). Differences in outcome between early versus delayed BEV treatment of recurrent GB are not well defined. We examined the relationship between the time of start of BEV treatment and outcomes in patients with recurrent GB. Methods: In this retrospective chart review derived from our longitudinal database, we identified patients with recurrent GB between 2001 and 2011, who were treated with BEV alone or BEV-containing regimens. Data was analyzed to determine overall survival (OS) from time of diagnosis and progression free survival (PFS) from time of BEV start. Early BEV was defined as start of BEV treatment at first recurrence, while delayed BEV was defined as start of treatment at second recurrence or later. Results: A total of 298 patients with recurrent GB who received BEV were identified, of whom 149 patients received early BEV, 134 patients received delayed BEV, and 15 patients who were excluded because they received BEV upfront. There were no significant differences in the age, sex, performance status and extent of resection between patients treated with early BEV and those treated with delayed BEV. The median time from diagnosis to first recurrence was more than 6 months (mos.) for both groups (6.5 mos. for early BEV and 7.6 mos. for delayed BEV, p = 0.01). The median time from diagnosis to start of BEV was 7.9 mos. for patients with early BEV and 15.6 mos. for patients with delayed BEV (p<0.001). There was no significant difference in PFS between patients that received early BEV and those that received delayed BEV (5.73 mos. vs. 4.33 mos., p = 0.07). Patients who were treated with delayed BEV had longer OS when compared to those treated with early BEV (25.9 mos. vs. 19.7 mos., p = 0.0002). Conclusions: In patients with recurrent GB, there was no significant difference in PFS between early and delayed BEV; however, patients treated with delayed BEV have longer OS when compared to those treated with early BEV. These results indicate that delaying treatment with BEV is not detrimental and may be associated with a favorable survival outcome.

Probabilities for separating sets of order statistics

Consider a set of order statistics that arise from sorting samples from two different populations, each with their own, possibly different distribution functions. The probability that these order statistics fall in disjoint, ordered intervals and that of the smallest statistics, a certain number come from the first populations is given in terms of the two distribution functions. The result is applied to computing the joint probability of the number of rejections and the number of false rejections for the Benjamini-Hochberg false discovery rate procedure.

Fast Computation by Block Permanents of Cumulative Distribution Functions of Order Statistics from Several Populations

The joint cumulative distribution function for order statistics arising from several different populations is given in terms of the distribution functions of the populations. The computational cost of our formula in the case of two populations is still exponential in the worst case, but it is a dramatic improvement compared to the general formula by Bapat and Beg. In the case when only the joint distribution function of a subset of the order statistics of fixed size is needed, the complexity is polynomial, for the case of two populations.

Pre-clinical development of cord blood-derived progenitor cell graft expanded ex vivo with cytokines and the polyamine copper chelator tetraethylenepentamine

BACKGROUND

We have previously demonstrated that the copper chelator tetraethylenepentamine (TEPA) enables preferential expansion of early hematopoietic progenitor cells (CD34+CD38-, CD34+CD38-Lin-) in human umbilical cord blood (CB)-derived CD34+ cell cultures. This study extends our previous findings that copper chelation can modulate the balance between self-renewal and differentiation of hematopoietic progenitor cells.

METHODS

In the present study we established a clinically applicative protocol for large-scale ex vivo expansion of CB-derived progenitors. Briefly, CD133+ cells, purified from CB using Miltenyi Biotec's (Bergisch Gladbach, Germany) CliniMACS separation device and the anti-CD133 reagent, were cultured for 3 weeks in a clinical-grade closed culture bag system, using the chelator-based technology in combination with early-acting cytokines (SCF, thrombopoietin, IL-6 and FLT-3 ligand). This protocol was evaluated using frozen units derived from accredited cord blood banks.

RESULTS

Following 3 weeks of expansion under large-scale culture conditions that were suitable for clinical manufacturing, the median output value of CD34+ cells increase by 89-fold, CD34+CD38- increase by 30-fold and CFU cells (CFUc) by 172-fold over the input value. Transplantation into sublethally irradiated non-obese diabetic (NOD/SCID) mice indicated that the engraftment potential of the ex vivo expanded CD133+ cells was significantly superior to that of unexpanded cells: 60+/-5.5% vs. 21+/-3.5% CD45+ cells, P=0.001, and 11+/-1.8% vs. 4+/-0.68% CD45+CD34+ cells, P=0.012, n=32, respectively.

DISCUSSION

Based on these large-scale experiments, the chelator-based ex vivo expansion technology is currently being tested in a phase 1 clinical trial in patients undergoing CB transplantation for hematological malignancies.