18F-Fluorocholine PET uptake correlates with pathologic evidence of recurrent tumor after stereotactic radiosurgery for brain metastases.

PURPOSE: Radiographic changes of brain metastases after stereotactic radiosurgery (SRS) can signify tumor recurrence and/or radiation necrosis (RN); however, standard imaging modalities cannot easily distinguish between these two entities. We investigated whether 18F-Fluorocholine uptake in surgical samples of the resected lesions correlates with pathologic evidence of recurrent tumor and PET imaging. METHODS: About 14 patients previously treated with SRS that developed radiographic changes were included. All patients underwent a preoperative 40-min dynamic PET/CT concurrent with 392 ± 11 MBq bolus injection of 18F-Fluorocholine. 18F-Fluorocholine pharmacokinetics were evaluated by standardized uptake value (SUV), graphical analysis (Patlak plot; KiP) and an irreversible two-compartment model (K1, k2, k3, and Ki). 12 out of 14 patients were administered an additional 72 ± 14 MBq injection of 18F-Fluorocholine 95 ± 26 minutes prior to surgical resection. About 113 resected samples from 12 patients were blindly reviewed by a neuropathologist to assess the viable tumor and necrotic content, microvascular proliferation, reactive gliosis, and mono- and polymorphonuclear inflammatory infiltrates. Correlation between these metrics 18F-Fluorocholine SUV was investigated with a linear mixed model. Comparison of survival distributions of two groups of patients (population median split of PET SUVmax) was performed with the log-rank test. RESULTS: Exactly 10 out of 12 patients for which surgical samples were acquired exhibited pathologic recurrence. Strong correlation was observed between SUVmax as measured from a surgically removed sample with highest uptake and by PET (Pearson's r = 0.66). Patients with 18F-Fluorocholine PET SUVmax > 6 experienced poor survival. Surgical samples with viable tumor had higher 18F-fluorocholine uptake (SUV) than those without tumor (4.5 ± 3.7 and 2.6 ± 3.0; p = 0.01). 18F-fluorocholine count data from surgical samples is driven not only by the percentage viable tumor but also by the degree of inflammation and reactive gliosis (p ≤ 0.02; multivariate regression). CONCLUSIONS: 18F-Fluorocholine accumulation is increased in viable tumor; however, inflammation and gliosis may also lead to elevated uptake. Higher 18F-Fluorocholine PET uptake portends worse prognosis. Kinetic analysis of dynamic 18F-Fluorocholine PET imaging supports the adequacy of the simpler static SUV metric.

Factors associated with a primary surgical approach for sinonasal squamous cell carcinoma.

BACKGROUND AND OBJECTIVES: Primary surgery is the preferred treatment of T1-T4a sinonasal squamous cell carcinoma (SNSCC). METHODS: Patients with SNSCC in the National Cancer Data Base (NCDB) were analyzed. Factors that contributed to selecting primary surgical treatment were examined. Overall survival (OS) in surgical patients was analyzed. RESULTS: Four-thousand seven hundred and seventy patients with SNSCC were included. In T1-T4a tumors, lymph node metastases, maxillary sinus location, and treatment at high-volume centers were associated with selecting primary surgery. When primary surgery was utilized, tumor factors and positive margin guided worse OS. Adjuvant therapy improved OS in positive margin resection and advanced T stage cases. CONCLUSIONS: Tumor and non-tumor factors are associated with selecting surgery for the treatment of SNSCC. When surgery is selected, tumor factors drive OS. Negative margin resection should be the goal of a primary surgical approach. When a positive margin resection ensues, adjuvant therapy may improve OS.

The medial transorbital approach in cranioendoscopic skull base tumor resections for locally advanced tumors.

BACKGROUND: Orbital structure preservation and avoidance of facial incisions without compromising oncological outcome are key to maintaining function and quality of life in locally advanced sinonasal tumor surgery. A transorbital approach at our institution has proven invaluable during cranioendoscopic skull base tumor resections and there are few descriptions of this in the literature. METHODS: An IRB-approved retrospective chart review was conducted at a tertiary cancer center for patients between 2020 and 2022 undergoing cranioendoscopic tumor resections utilizing a transorbital approach. Data collected included histopathology, sinus origin, disease extent, stage, operative details, length of stay, neo-adjuvant treatment and adjuvant treatment. Recurrence, survival, and complication rates were assessed. RESULTS: Four patients were identified for inclusion, including a SMARCB1-deficient carcinoma, esthesioneuroblastoma, squamous cell carcinoma and meningioma. All patients had resection of gross and microscopic disease with preservation of orbital contents. Post-operatively, one patient had mild diplopia on inferior gaze, all other patients had normal vision. Median follow-up was 9.5 months. One patient had recurrence of disease intracranially. CONCLUSIONS: The cranioendoscopic approach with a medial transorbital incision has multiple benefits. It avoids the need for a Weber-Ferguson incision with associated facial scar, allows for early intra-operative assessment for orbital invasion using tactile feedback and safe dissection of disease while protecting the globe and rectus muscles. This leads to preservation of eye function while ensuring an oncological resection. Other advantages include ligation of the anterior ethmoid artery and access for reconstruction of the medial orbital wall.

Prognostic and radiographic correlates of a prospectively collected molecularly profiled cohort of IDH1/2-wildtype astrocytomas.

BACKGROUND: In the molecular era, the relevance of tumor grade for prognostication of IDH1/2-wildtype (WT) gliomas has been debated. It has been suggested that histologic grade II and III astrocytomas with molecular features of glioblastoma, IDH1/2-WT have a similar prognosis to glioblastoma and should be considered for the same clinical trials. METHODS: We integrated prospective clinical sequencing from 564 patients with IDH1/2-WT gliomas (26 grade II, 71 grade III and 467 grade IV) with clinical and radiographic data to assess associations between molecular features, grade and outcome. RESULTS: Compared to histologic grade IV IDH1/2-WT astrocytomas, histologic grade II astrocytomas harbor fewer chromosome 7/10 alterations (P = 0.04), EGFR amplifications (P = 0.022) and alterations in cell-cycle effectors (P = 1.9e-11), but a similar frequency of TERT promoter mutations. In contrast, there is no difference in the frequency of these canonical molecular features in histologic grade III vs. IV IDH1/2-WT disease. Progression-free (PFS) and overall survival (OS) for histologic grade II tumors were significantly longer than grade III tumors (P = 0.02 and P = 0.008, respectively), whereas there was no difference in PFS and OS for histologic grade III compared to grade IV tumors. Median PFS for histologic grade II, III and IV tumors was 19, 11 and 9 months, respectively. Median OS for the same tumors was 44, 23 and 23 months, respectively. In histologic grade II and III IDH1/2 WT tumors, gliomatosis is associated with the absence of cell-cycle alterations (P = 0.008) and enriched in grade II features (P = 0.1) and alterations in the PI3K-AKT pathway (P = 0.09). CONCLUSIONS: Grade II histology has genotypic and phenotypic associations with prognostic implications in IDH1/2-WT astrocytomas.

Genomic Correlates of Disease Progression and Treatment Response in Prospectively Characterized Gliomas.

PURPOSE: The genomic landscape of gliomas has been characterized and now contributes to disease classification, yet the relationship between molecular profile and disease progression and treatment response remain poorly understood.Experimental Design: We integrated prospective clinical sequencing of 1,004 primary and recurrent tumors from 923 glioma patients with clinical and treatment phenotypes. RESULTS: Thirteen percent of glioma patients harbored a pathogenic germline variant, including a subset associated with heritable genetic syndromes and variants mediating DNA repair dysfunctions (29% of the total) that were associated with somatic biallelic inactivation and mechanism-specific somatic phenotypes. In astrocytomas, genomic alterations in effectors of cell-cycle progression correlated with aggressive disease independent of IDH mutation status, arose preferentially in enhancing tumors (44% vs. 8%, P < 0.001), were associated with rapid disease progression following tumor recurrence (HR = 2.6, P = 0.02), and likely preceded the acquisition of alkylating therapy-associated somatic hypermutation. Thirty-two percent of patients harbored a potentially therapeutically actionable lesion, of whom 11% received targeted therapies. In BRAF-mutant gliomas, response to agents targeting the RAF/MEK/ERK signaling axis was influenced by the type of mutation, its clonality, and its cellular and genomic context. CONCLUSIONS: These data reveal genomic correlates of disease progression and treatment response in diverse types of glioma and highlight the potential utility of incorporating genomic information into the clinical decision-making for patients with glioma.

Ibrutinib Unmasks Critical Role of Bruton Tyrosine Kinase in Primary CNS Lymphoma.

Bruton tyrosine kinase (BTK) links the B-cell antigen receptor (BCR) and Toll-like receptors with NF-κB. The role of BTK in primary central nervous system (CNS) lymphoma (PCNSL) is unknown. We performed a phase I clinical trial with ibrutinib, the first-in-class BTK inhibitor, for patients with relapsed or refractory CNS lymphoma. Clinical responses to ibrutinib occurred in 10 of 13 (77%) patients with PCNSL, including five complete responses. The only PCNSL with complete ibrutinib resistance harbored a mutation within the coiled-coil domain of CARD11, a known ibrutinib resistance mechanism. Incomplete tumor responses were associated with mutations in the B-cell antigen receptor-associated protein CD79B. CD79B-mutant PCNSLs showed enrichment of mammalian target of rapamycin (mTOR)-related gene sets and increased staining with PI3K/mTOR activation markers. Inhibition of the PI3K isoforms p110α/p110δ or mTOR synergized with ibrutinib to induce cell death in CD79B-mutant PCNSL cells.Significance: Ibrutinib has substantial activity in patients with relapsed or refractory B-cell lymphoma of the CNS. Response rates in PCNSL were considerably higher than reported for diffuse large B-cell lymphoma outside the CNS, suggesting a divergent molecular pathogenesis. Combined inhibition of BTK and PI3K/mTOR may augment the ibrutinib response in CD79B-mutant human PCNSLs. Cancer Discov; 7(9); 1018-29. ©2017 AACR.See related commentary by Lakshmanan and Byrd, p. 940This article is highlighted in the In This Issue feature, p. 920.

Cox-2-derived PGE2 induces Id1-dependent radiation resistance and self-renewal in experimental glioblastoma.

BACKGROUND: In glioblastoma (GBM), Id1 serves as a functional marker for self-renewing cancer stem-like cells. We investigated the mechanism by which cyclooxygenase-2 (Cox-2)-derived prostaglandin E2 (PGE2) induces Id1 and increases GBM self-renewal and radiation resistance. METHODS: Mouse and human GBM cells were stimulated with dimethyl-PGE2 (dmPGE2), a stabilized form of PGE2, to test for Id1 induction. To elucidate the signal transduction pathway governing the increase in Id1, a combination of short interfering RNA knockdown and small molecule inhibitors and activators of PGE2 signaling were used. Western blotting, quantitative real-time (qRT)-PCR, and chromatin immunoprecipitation assays were employed. Sphere formation and radiation resistance were measured in cultured primary cells. Immunohistochemical analyses were carried out to evaluate the Cox-2-Id1 axis in experimental GBM. RESULTS: In GBM cells, dmPGE2 stimulates the EP4 receptor leading to activation of ERK1/2 MAPK. This leads, in turn, to upregulation of the early growth response1 (Egr1) transcription factor and enhanced Id1 expression. Activation of this pathway increases self-renewal capacity and resistance to radiation-induced DNA damage, which are dependent on Id1. CONCLUSIONS: In GBM, Cox-2-derived PGE2 induces Id1 via EP4-dependent activation of MAPK signaling and the Egr1 transcription factor. PGE2-mediated induction of Id1 is required for optimal tumor cell self-renewal and radiation resistance. Collectively, these findings identify Id1 as a key mediator of PGE2-dependent modulation of radiation response and lend insight into the mechanisms underlying radiation resistance in GBM patients.