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Purpose: With proper beam setup and optimization constraints in the treatment planning system, volumetric modulated arc therapy (VMAT) can improve target dose coverage and conformity while reducing doses to adjacent structures for whole breast radiation therapy. However, the low‐dose bath effect on critical structures, especially the heart and the ipsilateral lung, remains a concern. In this study, we present a VMAT technique with the jaw offset VMAT (JO‐VMAT) to reduce the leakage and scatter doses to critical structures for whole breast radiation therapy. Materials and methods: The data of 10 left breast cancer patients were retrospectively used for this study. CT images were acquired on a CT scanner (GE, Discovery) with the deep‐inspiration breath hold (DIBH) technique. The planning target volumes (PTVs) and the normal structures (the lungs, the heart, and the contralateral breast) were contoured on the DIBH scan. A 3D field‐in‐field plan (3D‐FiF), a tangential VMAT (tVMAT) plan, and a JO‐VMAT plan were created with the Eclipse treatment planning system. An arc treatment field with the x‐jaw closed across the central axis creates a donut‐shaped high‐dose distribution and a cylinder‐shaped low‐dose volume along the central axis of gantry rotation. Applying this setup with proper multi‐leaf collimator (MLC) modulation, the optimized plan potentially can provide sufficient target coverage and reduce unnecessary irradiation to critical structures. The JO‐VMAT plans involve 5–6 tangential arcs (3 clockwise arcs and 2–3 counterclockwise arcs) with jaw offsets. The plans were optimized with objective functions specified to achieve PTV dose coverage and homogeneity; For organs at risk (OARs), objective functions were specified individually for each patient to accomplish the best achievable treatment plan. For tVMAT plans, optimization constraints were kept the same except that the jaw offset was removed from the initial beam setup. The dose volume histogram (DVH) parameters were generated for dosimetric evaluation of PTV and OARs. Results: The D95% to the PTV was greater than the prescription dose of 42.56 Gy for all the plans. With both VMAT techniques, the PTV conformity index (CI) was statistically improved from 0.62 (3D‐FiF) to 0.83 for tVMAT and 0.84 for JO‐VMAT plans. The difference in the homogeneity index (HI) was not significant. The Dmax to the heart was reduced from 12.15 Gy for 3D‐FiF to 8.26 Gy for tVMAT and 7.20 Gy for JO‐VMAT plans. However, a low‐dose bath effect was observed with tVMAT plans to all the critical structures including the lungs, the heart, and the contralateral breast. With JO‐VMAT, the V5Gy and V2Gy of the heart were reduced by 32.7% and 15.4% compared to 3D‐FiF plans. Significantly, the ipsilateral lung showed a reduction in mean dose (4.65–3.44 Gy) and low dose parameters (23.4% reduction for V5Gy and 10.7% reduction for V2Gy) for JO‐VMAT plans compared to the 3D‐FiF plans. The V2Gy dose to the contralateral lung and breast was minimal with JO‐VMAT techniques. Conclusion: A JO‐VMAT technique was evaluated in this study and compared with 3D‐FiF and tVMAT techniques. Our results showed that the JO‐VMAT technique can achieve clinically comparable coverage and homogeneity and significantly improve dose conformity within PTV. Additionally, JO‐VMAT eliminated the low‐dose bath effect at all OARs evaluation metrics including the ipsilateral/contralateral lung, the heart, and the contralateral breast compared to 3D‐FiF and tVMAT. This technique is feasible for the whole breast radiation therapy of left breast cancers. [ABSTRACT FROM AUTHOR]

Background: Optimal adjuvant chemotherapy after laparoscopic surgery in gastric cancer (GC) patients is still undefined. We aimed to evaluate the efficacy of S‐1 plus oxaliplatin (SOX) and capecitabine plus oxaliplatin (CAPOX) in patients with GC after laparoscopic gastrectomy. Methods: A non‐inferiority randomized controlled clinical trial was performed in China. Patients with advanced GC who underwent laparoscopic D2 gastrectomy were randomly assigned to receive SOX and CAPOX regimens. Results: In total, 191 patients were screened between May 2018 and June 2019, and 140 (73.3%) were included in the modified intent‐to‐treat analysis (mITT), of whom 69 and 71 were assigned to the SOX and CAPOX groups, respectively. The SOX group had similar 3‐year overall survival (OS) and disease‐free survival to the CAPOX group. Subgroup analysis revealed significantly better OS in the SOX group for male patients ([HR] = 0.395; 95% [CI], 0.153–1.019; p = 0.045), age >60 (HR = 0.219; 95% [CI], 0.064–0.753; p = 0.016), tumors in the gastric antrum (HR = 0.273; 95% [CI], 0.076–0.981; p = 0.047), and moderately differentiated tumors (HR = 0.338; 95% [CI], 0.110–1.041; p = 0.041). There were no significant differences observed in terms of adverse events and recurrence patterns between the two groups. Conclusion: Adjuvant SOX was non‐inferior to CAPOX treatments for patients with GC who underwent curative laparoscopic D2 gastrectomy. For male patients, aged >60 years, tumors in the gastric antrum, and moderately differentiated tumors, adjuvant SOX may achieve an improvement compared with CAPOX. [ABSTRACT FROM AUTHOR]

Grinding is a fundamental operation in craniotomy. Suitable grinding parameters will not only reduce force damage, but also ensure grinding efficiency. In this study, the regression equations of material removal rate and grinding force were obtained based on the theory of cortical bone grinding and full factorial test results, a multi-objective optimization based on the particle swarm algorithm was proposed for optimizing the grinding parameters: spindle speed, feed speed, and grinding depth in the grinding process. Two conflicting objectives, minimum grinding force and maximum material removal rate, were optimized simultaneously. The results revealed that the optimal grinding parameter combination and optimization results were as follows: spindle speed of 5000 rpm, feed rate of 60 mm/min, grinding depth of 0.6 mm, grinding force of 15.1 N, and material removal rate of 113.8 mm3/min. The parameter optimization result can provide theoretical guidance for selecting cortical bone grinding parameters in actual craniotomy. Graphical abstract [ABSTRACT FROM AUTHOR]