Surgeon experience in glioblastoma surgery of the elderly : a multicenter, retrospective cohort study

Purpose To assess the impact of individual surgeon experience on overall survival (OS), extent of resection (EOR) and surgery-related morbidity in elderly patients with glioblastoma (GBM), we performed a retrospective case-by-case analysis. Methods GBM patients aged≥65 years who underwent tumor resection at two academic centers were analyzed. The experience of each neurosurgeon was quantifed in three ways: (1) total number of previously performed glioma surgeries (lifetime experience); (2) number of surgeries performed in the previous fve years (medium-term experience) and (3) in the last two years (short-term experience). Surgeon experience data was correlated with survival (OS) and surrogate parameters for surgical quality (EOR, morbidity). Results 198 GBM patients (median age 73.0 years, median preoperative KPS 80, IDH-wildtype status 96.5%) were included. Median OS was 10.0 months (95% CI 8.0–12.0); median EOR was 89.4%. Surgery-related morbidity afected 19.7% patients. No correlations of lifetime surgeon experience with OS (P=.693), EOR (P=.693), and surgery-related morbidity (P=.435) were identifed. Adjuvant therapy was associated with improved OS (PConclusion Less experienced neurosurgeons achieve similar surgical results and outcome in elderly GBM patients within the setting of academic teaching hospitals. Adjuvant treatment and avoidance of surgery-related morbidity are crucial forgenerating a treatment beneft for this cohort.Peer reviewe

Theoretical Considerations about Total Reflection X-Ray Fluorescence for Light Element Analysis at Various Excitation Energies and Experimental Results.

TXRF with a special energy dispersive spectrometer is well suited for analyzing light elements, such as C, N, O, F, Na, Mg and Al. The elemental sensitivity is mainly influenced by the energy of the exciting radiation. Different excitation energies from 1.7 to 17.5keV and the resulting background due to scattering on the reflector substrate under total reflection conditions were studied theoretically. The angular dependence of the fluorescence signal from low-Z atoms implanted in Si, excited by monoenergetic radiation of various energies, was calculated. The same was also done for Ti atoms implanted in Si, and compared with the measured results. The excitation energy in the experiments was monochromatized Cr-Kα radiation. In addition, results obtained with synchrotron radiation as the excitation source are presented. A detection limit of 200fg for Mg has been obtained