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Objective: Compared to microscopes, exoscopes have advantages in field-depth, ergonomics, and educational value. Exoscopes are especially well-poised for adaptation into fluorescence-guided surgery (FGS) due to their excitation source, light path, and image processing capabilities. We evaluated the feasibility of near-infrared FGS using a 3-dimensional (3D), 4 K exoscope with nearinfrared fluorescence imaging capability. We then compared it to the most sensitive, commercially-available near-infrared exoscope system (3D and 960 p). In-vitro and intraoperative comparisons were performed. Methods: Serial dilutions of indocyanine-green (1-2000 µg/mL) were imaged with the 3D, 4 K Olympus Orbeye (system 1) and the 3D, 960 p VisionSense Iridium (system 2). Near-infrared sensitivity was calculated using signal-to-background ratios (SBRs). In addition, three patients with brain tumors were administered indocyanine-green and imaged with system 1, with two also imaged with system 2 for comparison. Results: Systems 1 and 2 detected near-infrared fluorescence from indocyanine green concentrations of >250 µg/L and >31.3 µg/L, respectively. Intraoperatively, system 1 visualized strong near-infrared fluorescence from two, strongly gadoliniumenhancing meningiomas (SBR=2.4, 1.7). The high-resolution, bright images were sufficient for the surgeon to appreciate the underlying anatomy in the near-infrared mode. However, system 1 was not able to visualize fluorescence from a weakly-enhancing intraparenchymal metastasis. In contrast, system 2 successfully visualized both the meningioma and the metastasis but lacked high resolution stereopsis. Conclusion: Three-dimensional exoscope systems provide an alternative visualization platform for both standard microsurgery and near-infrared fluorescent guided surgery. However, when tumor fluorescence is weak (i.e., low fluorophore uptake, deep tumors), highly sensitive near-infrared visualization systems may be required. [ABSTRACT FROM AUTHOR]

In Gamma Knife (GK) radiosurgery, dose rate decreases during the life cycle of its radiation source, extending treatment times. Prolonged treatments influence the amount of sublethal radiation injury that is repaired during exposure, and is associated with decreased biologically-equivalent dose (BED). We assessed the impact of treatment times on clinical outcomes following GK of the trigeminal nerve - a rare clinical model to isolate the effects of treatment times. This is a retrospective analysis of 192 patients with facial pain treated across three source exchanges. All patients were treated to 80 Gy with a single isocenter. Treatment time was analyzed in terms of patient anatomy-specific dose rate, as well as BED calculated from individual patient beam-on times. An outcome tool measuring pain in three distinct domains (pain intensity, interference with general and oro-facial activities of daily living), was administered before and after intervention. Multivariate linear regression was performed with dose rate/BED, brainstem dose, sex, age, diagnosis, and prior intervention as predictors. BED was an independent predictor of the degree of improvement in all three dimensions of pain severity. A decrease in dose rate by 1.5 Gy/min corresponded to 31.8% less improvement in the overall severity of pain. Post-radiosurgery incidence of facial numbness was increased for BEDs in the highest quartile. Treatment time is an independent predictor of pain outcomes, suggesting that prescription dose should be customized to ensure iso-effective treatments, while accounting for the possible increase in adverse effects at the highest BEDs. [ABSTRACT FROM AUTHOR]

Objective  Radiation therapy represents an uncommon but important component of treatment plans for some pituitary adenomas (PAs). Although radiation therapy has been used to treat pituitary adenomas for over a century, general trends in the usage of radiation therapy for this purpose have not been reviewed. Additionally, there are few large studies evaluating how radiation therapy is used for the treatment of these benign tumors. Investigating these trends and identifying any variations in radiation therapy utilization would help to better inform treatment decisions and improve patient outcomes. Design  Present study is a retrospective analysis of cases using the National Cancer Database. Setting  The research was organized at a tertiary academic medical center. Participants  Patients were diagnosed with pituitary adenoma between 2004 and 2014 within the National Cancer Database (NCDB). Methods  Temporal trends in the usage of radiation therapy to treat pituitary adenoma were analyzed through a retrospective analysis of 77,142 pituitary adenoma cases from the NCDB between 2004 and 2014. Univariate and multivariate analyses were to examine the relationship between patient, tumor, and treatment factors, and the incorporation of radiation therapy into the treatment of pituitary adenomas. We adjusted for potential confounders such as age, sex, race, comorbidity score, facility type, and year of diagnosis. Results  A total of 77,142 patients met inclusion criteria. Inclusion of radiation therapy in pituitary adenoma treatment was 8.0% in 2004 and steadily declined to a low of 3.1% in 2014. Overall, patients were less likely to receive radiation for their pituitary adenoma over time (p  < 0.001). Similarly, patients were found to be less likely to receive any type of treatment for PA over time (p  < 0.001). Multivariable evaluation found patients who were female, between 54 and 64 years of age, or treated at either a Comprehensive Community Cancer Program or an Integrated Network Cancer Program were more likely to receive radiation as part of their pituitary adenoma treatment (p  < 0.001, odds ratio [OR] = 2.01, confidence interval [CI]: 1.54–2.63; p  < 0.001, OR = 1.84, CI: 1.38–2.44, respectively). Patients were less likely to receive radiation for their PA if they were African American (p  < 0.001, OR = 0.81, CI: 0.72–0.91). Logistic regression also identified a progressive increase in the likelihood of receiving radiation after a PA diagnosis with increasing tumor size starting with microscopic tumors, peaking at 4 to 5 cm (p  < 0.001; OR = 15.57; CI: 12.20–19.87). Conclusion  In this sample of pituitary adenoma patients treated at NCDB institutions between 2004 and 2014, we found a steady decline in the incorporation of radiation therapy in treatment, as well as in the use of any type of intervention for PA treatment, suggesting a rise in noninterventional observation of PA. [ABSTRACT FROM AUTHOR]

Introduction  Olfactory groove meningiomas (OGMs) are often associated with loss of smell following resection. Loss of smell has a measurable impact on quality of life. Smell preservation has been previously described in open approaches for early stage or unilateral OGMs. Evidence of smell preservation in endoscopic approaches is lacking. Design  A multi-institutional retrospective review was performed on consecutive patients who underwent unilateral endoscopic endonasal resection of OGM. A gross total resection was achieved with preservation of the contralateral olfactory cleft and bulb. Olfactory function was assessed with a six-point olfactory symptom score and the Sniffin' Sticks 12-item smell identification test (SS-12). Contralateral olfactory bulb volume was measured on postoperative magnetic resonance imaging. Results  Four patients (age 42.0 ± 7.5, 75% female) were assessed. Olfactory function was assessed at 21.8 ± 5.6 months following surgery. All patients reported some degree of smell preservation (75% described a slight/mild impairment in smell or better). Olfactory identification was preserved with an SS-12 score of 9 ± 1.4 (anosmia defined as ≤6). The olfactory bulb volume was calculated to be 47.4 ± 15.9 mm 3 (normal >40 mm 3). Conclusion  Smell preservation is possible following unilateral endoscopic endonasal resection of carefully selected OGM. [ABSTRACT FROM AUTHOR]

Introduction: Patients with small cell lung cancer (SCLC) brain metastasis (BM) typically receive whole brain radiotherapy (WBRT) as data regarding upfront radiosurgery (SRS) in this setting are sparse. Methods: Patients receiving SRS for SCLC BM without prior brain radiation were identified at three U.S. institutions. Overall survival (OS), freedom from intracranial progression (FFIP), freedom from WBRT (FFWBRT), and freedom from neurologic death (FFND) were determined from time of SRS. Results: Thirty-three patients were included with a median of 2 BM (IQR 1-6). Median OS and FFIP were 6.7 and 5.8 months, respectively. Median FFIP for patients with =2 versus >2 BM was 7.1 versus 3.6 months, p=0.0303. Eight patients received salvage WBRT and the 6-month FFWBRT and FFND were 87.8%. and 90.1%, respectively. Conclusions: Most SCLC patients with BM who received upfront SRS avoided WBRT and neurologic death, suggesting that SRS may be an option in select patients. [ABSTRACT FROM AUTHOR]

Introduction We sought to identify factors associated with increased length of stay (LOS) and morbidity in patients undergoing resection of pituitary macroadenomas. Methods We reviewed records of 203 consecutive patients who underwent endoscopic endonasal resection of a pituitary macroadenoma (mean age = 55.7 [16-88]) years, volume = 11.3 (1.0-134.3) cm3. Complete resection was possible in 60/29.6% patients. Mean follow-up was 575 days. Multivariate logistic regression was performed using MATLAB. Results Mean LOS was 4.67 (1-66) days and was associated with CSF leak (p = 0.025), lumbar drain placement (p = 0.041; n = 8/3.9% intraoperative, n = 20/9.9% postoperative), and any infection (p = 0.066). Age, diabetes insipidus (n = 17/8.37%), and syndrome of inappropriate antidiuretic hormone secretion (n = 12/5.9%) were not associated with increased LOS (p > 0.2). Postoperative CSF leak in the hospital (n = 21/ 10.3%) was associated with intraoperative CSF leak (p = 0.002; n = 82/40.4%) and complete resection (p = 0.012). There was no significant association (p > 0.1) between postoperative CSF leak in the hospital following surgery and the use of a fat graft (n = 61/30.1%), nasoseptal flap (155/76.4%), or perioperative lumbar drain placement (n = 8/3.94%). Conclusion Complete resection is associated with increased risk of CSF leak and LOS. Operative strategies including placement of fat graft, nasoseptal flap, or intraoperative lumbar drain placement may have limited value in reducing the risk of postoperative CSF leak. [ABSTRACT FROM AUTHOR]

An abstract of a study which examined patients undergoing extended endoscopic approach (EEA) for skull base tumors is presented.

Purpose: The purpose of this study was to evaluate the feasibility and safety of dose-escalated proton beam therapy for treating chordomas and chondrosarcomas of the skull base and spine. Methods: A prospective cohort of 54 patients (42 with chordomas and 12 with chondrosarcomas) was enrolled between 2010 and 2018. The primary endpoints were feasibility and <20% rate of acute grade ≥3 toxicity, and secondary endpoints included cancer-specific outcomes and toxicities. Patients were followed with magnetic resonance imaging or computed tomography at 3-month intervals. Proton beam therapy was delivered with doses up to 79.2 Gy using protons only, combination protons/intensity modulated radiation therapy (IMRT), or IMRT only., Results: Feasibility endpoints were met, with only 2 out of 54 patient radiation therapy plans failing to meet dosimetric constraints with protons, and 4 out of 54 experiencing a delay or treatment break >5 days, none for toxicities related to treatment. There were no grade 4 acute toxicities and 1 grade 3 acute toxicity (sensory neuropathy). The only 2 grade 3 late toxicities recorded, osteoradionecrosis and intranasal carotid blowout (mild and not emergently treated), occurred in a single patient. We report overall survival as 83% at 5 years, with local failure-free survival and progression-free survival rates of 72% and 68%, respectively. Five patients developed distant disease, and among the 9/54 patients who died, 4 deaths were not attributed to treatment or recurrence., Conclusions: Our findings suggest that high-dose proton therapy alone or in combination with IMRT is a safe and effective treatment option for chordomas and chondrosarcomas of the skull base and spine., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

Accurate differentiation between tumor progression (TP) and pseudoprogression remains a critical unmet need in neurooncology. 18 F-fluciclovine is a widely available synthetic amino acid PET radiotracer. In this study, we aimed to assess the value of 18 F-fluciclovine PET for differentiating pseudoprogression from TP in a prospective cohort of patients with suspected radiographic recurrence of glioblastoma. Methods: We enrolled 30 glioblastoma patients with radiographic progression after first-line chemoradiotherapy for whom surgical resection was planned. The patients underwent preoperative 18 F-fluciclovine PET and MRI. The relative percentages of viable tumor and therapy-related changes observed in histopathology were quantified and categorized as TP (≥50% viable tumor), mixed TP (<50% and >10% viable tumor), or pseudoprogression (≤10% viable tumor). Results: Eighteen patients had TP, 4 had mixed TP, and 8 had pseudoprogression. Patients with TP/mixed TP had a significantly higher 40- to 50-min SUV max (6.64 + 1.88 vs. 4.11 ± 1.52, P  = 0.009) than patients with pseudoprogression. A 40- to 50-min SUV max cutoff of 4.66 provided 90% sensitivity and 83% specificity for differentiation of TP/mixed TP from pseudoprogression (area under the curve [AUC], 0.86). A maximum relative cerebral blood volume cutoff of 3.672 provided 90% sensitivity and 71% specificity for differentiation of TP/mixed TP from pseudoprogression (AUC, 0.779). Combining a 40- to 50-min SUV max cutoff of 4.66 and a maximum relative cerebral blood volume of 3.67 on MRI provided 100% sensitivity and 80% specificity for differentiating TP/mixed TP from pseudoprogression (AUC, 0.95). Conclusion: 18 F-fluciclovine PET uptake can accurately differentiate pseudoprogression from TP in glioblastoma, with even greater accuracy when combined with multiparametric MRI. Given the wide availability of 18 F-fluciclovine, larger, multicenter studies are warranted to determine whether amino acid PET with 18 F-fluciclovine should be used in the routine posttreatment assessment of glioblastoma., (© 2023 by the Society of Nuclear Medicine and Molecular Imaging.)