Feasibility of intraoperative radiotherapy with X-rays for the treatment of superior sulcus tumours

Abstract

Background Preoperative concurrent chemoradiotherapy (CCRT) followed by surgery has become the standard treatment for potentially resectable superior sulcus (SS) tumours. To date, intraoperative radiotherapy (IORT) for SS tumour treatment is primarily performed via brachytherapy; it achieves high local control, but has no influence on overall survival. Therefore, a novel therapy is required to increase the local control of SS tumours. The purpose of this study was to evaluate the feasibility and safety of IORT with low-energy X-rays for treating SS tumours. Methods Patients diagnosed with stage IIB-IIIA SS tumours with chest wall invasion and scheduled to undergo surgery were eligible for this prospective pilot study. Every patient was discussed at a lung cancer multidisciplinary team meeting. Patients with potentially resectable tumour were scheduled for neoadjuvant chemoradiotherapy followed by surgery, while those with resectable tumour were scheduled to receive surgery alone. Neoadjuvant chemotherapy consisted of two cycles of platinum-based doublet chemotherapy. Concurrent radiotherapy of 50 Gy in 25 fractions over 5 weeks was performed via intensity-modulated radiation therapy. IORT was administered to the tumour bed with close margin. The primary endpoint was acute toxicity and secondary endpoints were late spinal cord and brachial plexus toxicity. Results Between August 22, 2014 and November 30, 2017, we enrolled nine patients (seven males and two females). Anaemia was the most common acute complication, with grade 3 anaemia occurring in three patients who received preoperative CCRT. Other side effects included pneumonia (1 patient), prolonged air leakage (1), and grade 1 brachial plexus injury (1). The average follow-up period was 29.4 (range; 13.3-50.4) months. All patients are alive. Distant metastasis was observed in two patients, one with contralateral lung metastasis and another with pericardial metastasis. Conclusions IORT with low-energy X-rays is a technically feasible and relatively safe treatment modality for patients with superior pulmonary sulcus tumours.

Construction of second-order six-dimensional Hamiltonian-conserving scheme

“…Some examples are the second-order implicit symplectic midpoint rule (Brown 2006), implicit schemes with adaptive step size control (Seyrich & Lukes-Gerakopoulos 2012), and explicit and implicit combined symplectic schemes (Preto & Saha 2009;Kopáček et al 2010;Lubich et al 2010;Zhong et al 2010;Mei et al 2013aMei et al , 2013b. There are extended phase-space explicit symplectic-like or symplectic methods (Liu et al 2016;Luo et al 2017;Li & Wu 2017;Christian & Chan 2021;Pan et al 2021), and explicit symplectic algorithms (Wang et al 2021a(Wang et al , 2021b(Wang et al , 2021cWu et al 2021). These loworder symplectic or symplectic-like integrations have been successfully applied to Hamiltonian systems describing the motions of particles in curved spacetimes and the motions of spinning compact binaries.…”