Proton versus photon adjuvant radiotherapy: a multicenter comparative evaluation of recurrence following spinal chordoma resection.

OBJECTIVE: Chordomas are rare tumors of the skull base and spine believed to arise from the vestiges of the embryonic notochord. These tumors are locally aggressive and frequently recur following resection and adjuvant radiotherapy. Proton therapy has been introduced as a tissue-sparing option because of the higher level of precision that proton-beam techniques offer compared with traditional photon radiotherapy. This study aimed to compare recurrence in patients with chordomas receiving proton versus photon radiotherapy following resection by applying tree-based machine learning models. METHODS: The clinical records of all patients treated with resection followed by adjuvant proton or photon radiotherapy for chordoma at Mayo Clinic were reviewed. Patient demographics, type of surgery and radiotherapy, tumor recurrence, and other variables were extracted. Decision tree classifiers were trained and tested to predict long-term recurrence based on unseen data using an 80/20 split. RESULTS: Fifty-three patients with a mean ± SD age of 55.2 ± 13.4 years receiving surgery and adjuvant proton or photon therapy to treat chordoma were identified; most patients were male. Gross-total resection was achieved in 54.7% of cases. Proton therapy was the most common adjuvant radiotherapy (84.9%), followed by conventional or external-beam radiation therapy (9.4%) and stereotactic radiosurgery (5.7%). Patients receiving proton therapy exhibited a 40% likelihood of having recurrence, significantly lower than the 88% likelihood observed in those treated with nonproton therapy. This was confirmed on logistic regression analysis adjusted for extent of tumor resection and tumor location, which revealed that proton adjuvant radiotherapy was associated with a decreased risk of recurrence (OR 0.1, 95% CI 0.01-0.71; p = 0.047) compared with photon therapy. The decision tree algorithm predicted recurrence with an accuracy of 90% (95% CI 55.5%-99.8%), with the lowest risk of recurrence observed in patients receiving gross-total resection with adjuvant proton therapy (23%). CONCLUSIONS: Following resection, adjuvant proton therapy was associated with a lower risk of chordoma recurrence compared with photon therapy. The described machine learning models were able to predict tumor progression based on the extent of tumor resection and adjuvant radiotherapy modality used.

Two-Stage Resection of a Giant Trigeminal Schwannoma in a Non-Neurofibromatosis Type 2 Pediatric Patient: A Case Report, Systematic Review, and Intraoperative Video.

BACKGROUND: Trigeminal schwannoma is an uncommon tumor in pediatric patients. Several surgical approaches have been described in the literature. METHODS: The case of an 11-year-old boy with a giant dumbbell-shaped trigeminal schwannoma removed through a 2-stage approach was presented with an intraoperative video. Using PubMed and Scopus, the literature on trigeminal schwannoma in pediatric patients was searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. RESULTS: The search strategy yielded 312 titles, of which 13 were included in the review. Cases of trigeminal schwannoma were described, with a highly variable clinical presentation and anatomical arrangement in cranial fossae. Two-stage approaches were reported, although most studies described single-stage approaches. Common postoperative outcomes were a range of disturbances of cranial nerve V. CONCLUSIONS: The surgical approach varies based on the tumor conformation. However, a 2-stage pterional subtemporal and semisitting retrosigmoid approach is a safe, practical, and effective strategy for the removal of dumbbell-shaped trigeminal schwannoma in a pediatric patient.

Cerebral Amyloid Angiopathy and Atrial Fibrillation: An up to Date Case Report.

Concurrent Cerebral Amyloid Angiopathy (CAA) and Atrial Fibrillation are becoming an increasingly common dilemma in clinical practice due to the aging population and the comorbidities associated with it. In such patients, the physician must appreciate and strike the difficult balance between the risk of ischemic strokes from atrial fibrillation on one hand, and that of intracerebral hemorrhage from coexisting CAA on the other. Anticoagulation is necessary for the former but potentially deleterious for the latter. In this case report, we present the case of a 67-year-old woman with a long history of atrial fibrillation on rivaroxaban who recently began to experience recurrent transient neurological deficits that were later diagnosed as amyloid spells related to concomitant CAA. While there is no clear-cut consensus in published literature on how to best manage these patients regarding the use of anticoagulation, it is recommended to involve a multidisciplinary team for optimal management of these patients.

Crystal structures of a dodecameric multicopper oxidase from Marinithermus hydrothermalis.

Multicopper oxidases (MCOs) represent a diverse family of enzymes that catalyze the oxidation of either an organic or a metal substrate with concomitant reduction of dioxygen to water. These enzymes contain variable numbers of cupredoxin domains, two, three or six per subunit, and rely on four copper ions, a single type I copper and three additional copper ions organized in a trinuclear cluster (TNC), with one type II and two type III copper ions, to catalyze the reaction. Here, two crystal structures and the enzymatic characterization of Marinithermus hydrothermalis MCO, a two-domain enzyme, are reported. This enzyme decolorizes Congo Red dye at 70°C in the presence of high halide concentrations and may therefore be useful in the detoxification of industrial waste that contains dyes. In two distinct crystal structures, MhMCO forms the trimers seen in other two-domain MCOs, but differs from these enzymes in that four trimers interact to create a dodecamer. This dodecamer of MhMCO forms a closed ball-like structure and has implications for the sequestration of bound divalent metal ions as well as substrate accessibility. In each subunit of the dodecameric structures, a Trp residue, Trp351, located between the type I and TNC sites exists in two distinct conformations, consistent with a potential role in facilitating electron transfer in the enzyme.

Cardiac Screening to Mitigate the Risk of Sudden Cardiac Death in Middle Eastern and African Competitive Athletes. A Systematic Review.

OBJECTIVE: The study aims to review the literature regarding abnormalities predisposing to Sudden Cardiac Death (SCD) in young Middle Eastern and African competitive athletes between the years 2009-2019 and aims to assess cardiac pre-participation screening methods. METHODS: A PubMed search was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search targeted articles that reported the prevalence of cardiac abnormalities found in Middle Eastern and African athletes, and it also focused on comparing cardiac screening methods for assessment of athletes. RESULTS: our studies fell within the inclusion criteria and were included in the study. Results identified a shortage in the literature regarding prevalence rates of SCD in the Middle East and Africa. Additionally, there seems to be a lack of ethnicity-specific cardiac pre-participation screening programs in the region. Nevertheless, the prevalence of SCD-related abnormalities (HCM, ARVC, etc …) ranged from 0.47 to 4.29%. Included studies conveyed only male athletes with no reports on the female athletic population. CONCLUSION: The present study highlights a need to develop an efficient cardiac pre-participation screening program specific to Arab and African athletes due to their high false-positive rates in contrast to Caucasian athletes. Significant evidence proves that an adequate cardiac screening program can prevent SCD in young competitive athletes. Therefore, it is imperative that future studies highlight the prevalence of abnormalities directly related to SCD in order to create a valid screening program that can be implemented in the region to mitigate the risk of shocking events.