Utility of Prophylactic Cranial Irradiation for Limited Stage Small Cell Lung Cancer in the Modern Era with Magnetic Resonance Imaging Surveillance.

AIMS: To retrospectively analyse the impact of prophylactic cranial irradiation (PCI) on survival and intracranial progression in patients with limited stage small cell lung cancer (LS-SCLC) in the modern era of widespread magnetic resonance imaging brain screening. MATERIALS AND METHODS: Patients with LS-SCLC treated within our network between 2009 and 2020 who responded to initial therapy were stratified by receipt of PCI and stage of disease. A propensity score match analysis was carried out for stage II-III patients. Overall and neurological survival were defined as time to death and presumed death due to uncontrolled intracranial disease, respectively. Brain metastasis-free survival and symptomatic brain metastasis-free survival were defined as freedom from intracranial progression and symptomatic intracranial progression, respectively. The effect of PCI on these outcomes was assessed using Kaplan-Meier and Cox proportional hazards models. RESULTS: In total, 243 (69.6%) of 349 patients received PCI. On multivariate analysis in the propensity matched stage II-III cohort, PCI was a significant predictor of improved neurological survival (hazard ratio 0.23, 95% confidence interval 0.08-0.65; P = 0.01), brain metastasis-free survival (hazard ratio 0.25, 95% confidence interval 0.12-0.51; P < 0.01) and symptomatic brain metastasis-free survival (hazard ratio 0.21, 95% confidence interval 0.08-0.55; P < 0.01), but not improved overall survival. Two-year neurological survival estimates within the propensity matched cohort were 96.8% (95% confidence interval 87.6-99.2%) with PCI and 77.2% (95% confidence interval 63.0-86.4%) without PCI and 1- and 2-year estimates of incidence of brain metastases were 3.9% (95% confidence interval 1.3-11.7%) and 11.7% (95% confidence interval 5.6-23.5%) in the PCI group and 31.6% (95% confidence interval 22.1-43.9%) and 40.4% (95% confidence interval 29.2-54.0%) in the no PCI group, respectively. CONCLUSIONS: In the modern era of magnetic resonance imaging screening, PCI was associated with reduced incidence of intracranial progression in patients with stage II-III LS-SCLC who respond to initial therapy. This, importantly, translated to a decreased risk of neurological death within our propensity matched cohort, without significant improvement in overall survival.

Early outcomes after definitive chemoradiation therapy with Vienna/Venezia hybrid high-dose rate brachytherapy applicators for cervical cancer: A single-institution experience.

PURPOSE: The Vienna and Venezia (Elekta) are hybrid intracavitary/interstitial brachytherapy (BT) applicators for cervical cancers unsuitable for intracavitary BT alone to improve target coverage or reduce critical organ dose. There is limited outcome data with the use of these applicators outside published experience of the EMBRACE group. We report feasibility and early outcomes with the use of these hybrid applicators at our institution. METHODS AND MATERIALS: Hybrid applicators were used to treat 61 patients with cervical cancer from November 2011 to December 2019. Indications for hybrid applicator use were involvement of the vagina in 10 patients (16%), residual central or parametrial disease in 46 patients (75%), and a narrow introitus in 5 patients (9%). Toxicities were graded using the CTCAE v4.0. Outcomes were assessed with the Kaplan-Meier method. RESULTS: Median follow-up was 16 months (IQR 9-32 mos). Median HRCTV volume was 31.6 cm3 (IQR 25-48 cm3). Median HRCTV D90 was 86.1 Gy (IQR 84.3-88.0 Gy). In 54 patients with follow-up PET/CT at 3 months, complete initial imaging response locally was seen in 46 patients.Estimated 12-month Kaplan-Meier overall survival, locoregional control, distant control, and recurrence-free survival estimates were 86.9%, 80.6%, 73.8%, and 65.9%, respectively. The 12-month incidence of Grade 3+ GI/GU chronic toxicities was 5.7%, consisting of vesicovaginal fistula, rectovaginal fistula, and ureterovesical fistula. CONCLUSIONS: Our single-institution data support the use of the hybrid applicators, as an alternative to traditional BT applicators when clinically warranted. Use of hybrid applicators is feasible with adequate coverage of disease in the vagina and parametrium.

Luminescence concentration quenching mechanism in Gd2O3:Eu3+.

Luminescence concentration quenching in Gd2O3:Eu(3+) nanocrystals results from strong interactions among O(2-) ions and Eu(3+) ions. Because all synthesized Gd2O3:Eu(3+) nanocrystals present the same cubic crystalline phase regardless of Eu(3+) concentration, it is possible to study the optical properties as a function of the dopant concentration. The emission intensities and lifetime curves for Gd2O3:Eu(3+) were analyzed by a simple rate equation model to study the interaction between the O(2-) ions and Eu(3+) ions. The rate equation model considers that such interaction is driven by the following energy transfer processes: the direct energy transfer (O(2-) → Eu(3+)), back-transfer (Eu(3+) → O(2-)), and direct energy migration (Eu(3+) → Eu(3+)). The exact solution of this model agrees with the experimental results, luminescence concentration quenching is reproduced and the corresponding energy transfer rates are reported. Quantitative results suggest that the direct energy transfer and direct energy migration processes are the main responsible for the luminescence concentration quenching, whereas the back-transfer process promotes the Eu(3+) emission.

Surface reconstruction and decahedral structure of bimetallic nanoparticles.

We report on energetic surface reconstruction phenomena observed on bimetallic nanoparticle systems of AuPd and AuCu, similar to a resolidification effect observed during the cooling process in lead clusters. These binary alloy nanoparticles show the fivefold edges truncated, resulting in [100] facets on decahedral structures, an effect largely envisioned and reported theoretically, with no experimental evidence so far. We demonstrate experimentally as well as by computational simulations that this new eutectic structure is favored in such nanoalloy systems.