Complete pathological response to neoadjuvant treatment is associated with better survival outcomes in patients with soft tissue sarcoma: Results of a retrospective multicenter study

[Background] Locally advanced soft tissue sarcoma (STS) management may include neoadjuvant or adjuvant treatment by radiotherapy (RT), chemotherapy (CT) or chemoradiotherapy (CRT) followed by wide surgical excision. While pathological complete response (pCR) to preoperative treatment is prognostic for survival in osteosarcomas, its significance for STS is unclear. We aimed to evaluate the prognostic significance of pCR to pre-operative treatment on 3-year disease-free survival (3y-DFS) in STS patients.[Methods] This is an observational, retrospective, international, study of adult patients with primary non-metastatic STS of the extremities and trunk wall, any grade, diagnosed between 2008 and 2012, treated with at least neoadjuvant treatment and surgical resection and observed for a minimum of 3 years after diagnosis. The primary objective was to evaluate the effect of pCR. (≤5% viable tumor cells or ≥95% necrosis/fibrosis) on 3y-DFS. Effect on local recurrence-free survival (LRFS), distant recurrence-free survival (MFS) overall survival (OS) at 3 years was also analyzed. Statistical univariate analysis utilized chi-square independence test and odds ratio confidence interval (CI) estimate, multivariate analysis was performed using LASSO.[Results] A total of 330 patients (median age 56 years old, range:19–95) treated by preoperative RT (67%), CT (15%) or CRT (18%) followed by surgery were included. pCR was achieved in 74/330 (22%) of patients, of which 56/74 (76%) had received RT. 3-yr DFS was observed in 76% of patients with pCR vs 61% without pCR (p < 0.001). Multivariate analysis showed that pCR is statistically associated with better MFS (95% CI, 1.054–3.417; p = 0.033), LRFS (95% CI, 1.226–5.916; p = 0.014), DFS (95% CI, 1.165–4.040; p = 0.015) and OS at 3 years (95% CI, 1.072–5.210; p = 0.033).[Conclusions] In a wide, heterogeneous STS population we showed that pCR to preoperative treatment is prognostic for survival.Nanobiotix S.A., Paris, France.Peer reviewe

Initial investigation of alternative propellants for use with a low-power cylindrical hall thruster

This paper describes the investigations into the useof alternative propellants for Hall Effect thrusters at the University of Southampton. A broad comparative study into all non-synthetic, non-radioactive atomic elements has been undertaken with an aim to identifying potentially viable alternative propellants to the current leading propellant, xenon. The characteristics of 81 elements, from hydrogen to bismuth, are examined with particular focus on five criteria; atomic mass, ionisation energy, heating power, cost, and toxicity. Krypton, nitrogen, oxygen, lead, bismuth, sodium, iodine, calcium, selenium, cadmium, zinc, and magnesium have all been identified as potential propellants. The results of recent experiments to characterise the performance of the CHT-100 thruster developed at the University of Southampton using krypton propellant are also presented. The peak performance displayed by the thruster was T = 5.43mN, Isp = 1254 s, at an anode power of 258 W and efficiency of 13%. This characterisation forms the baseline for further investigations into alternative propellants

Performance investigation of zinc propellant in sub kW class hall thrusters

Zinc was successfully integrated and tested in sub-kW class Hall thrusters as an alternative propellant to xenon. The advantages of zinc include a high storage density, low first ionization energy, potentially high specific impulse and low cost. The third iteration (Mark 3) of a novel propellant storage and delivery system (PSDS) for solid propellants was tested and experimentally characterised, demonstrating operational zinc outputs up to 0.36 mg/s in sublimation mode with a peak of 8.2 mg/s near the melting point of zinc. The PSDS power consumption was approximately 20-30 W during thruster operation and 50 W in the start-up sequence. A 100 W laboratory cylindrical Hall thruster (CHT-100) was modified structurally and magnetically to couple with the PSDS Mark 3. Performance was measured during thruster operation on xenon, krypton and zinc with a mass flow rate of 5 SCCM to 10 SCCM, a discharge power of 50-150 W and an electromagnet current of 0.8 A on the main solenoid and 1.0 A on the secondary solenoid. Measured thrust was 1 mN during operation on zinc at an input power of 80 W and 1.2 mN during operation on krypton at an input power of 98 W. At an input power of 80 W the maximum measured specific impulse was 448 s during operation on zinc and 371 s during operation on krypton. Demonstration of throttling and PSDS redundancy in failure mode operation is discussed, as well as deposition and channel erosion

The operation of a low-power cylindrical Hall thruster with zinc as the propellant

There is a strong interest to develop electric propulsion systems that utilize alternative propellants to xenon, both forsmaller platforms with tighter budget, mass, and volume constraints, or for larger satellites that may otherwise depletethe world market resource. This is leading to the development of high performance electric propulsion systems, forexample Hall Effect Thrusters, which can operate on alternative propellants. Hall Thrusters (HTs) have been shownto function with a wide range of propellants including xenon, krypton, iodine, and more exotic propellants such aszinc, magnesium and bismuth. Their relatively simple annular topology makes them well suited to miniaturisation,however reduced component size has implications for the strength of the magnetic field, erosion of the channel, andthe level of heating present. The Cylindrical Hall Thruster (CHT) was proposed to address these issues, using arecessed annular channel to reduce the surface-to-volume ratio and a cusp magnetic field to contain the electrons. Acollaborative project between the University of Southampton and OHB Sweden has begun to characterise a low-powerCHT using firstly Krypton, and then to compare the performance to when using zinc as the propellant.The paper presents the results of the characterisation of the CHT-100 thruster using krypton, and development of thethruster for operating with zinc. The design of the CHT-100 is described, and also the setup of the test campaign usedto evaluate the thruster performance, with a pendulum thrust balance used to accurately record the thrust producedand therefore efficiency. Results from operating the CHT-100 on krypton are discussed.The in depth characterization of a propellant delivery system using zinc as the propellant are described. This involvesthermal analysis of the system,Further, the design of a low power (100 – 200 W) Hall Effect Thruster is discussed. The design process is described,including validation that it is capable of operating on alternative propellants. The manufactured thruster is illustratedand the magnetic field demonstrated to be that which is required

Complete pathological response to neoadjuvant treatment is associated with better survival outcomes in patients with soft tissue sarcoma: Results of a retrospective multicenter study

Background: Locally advanced soft tissue sarcoma (STS) management may include neoadjuvant or adjuvant treatment by radiotherapy (RT), chemotherapy (CT) or chemoradiotherapy (CRT) followed by wide surgical excision. While pathological complete response (pCR) to preoperative treatment is prognostic for survival in osteosarcomas, its significance for STS is unclear. We aimed to evaluate the prognostic significance of pCR to pre-operative treatment on 3-year disease-free survival (3y-DFS) in STS patients. Methods: This is an observational, retrospective, international, study of adult patients with primary non-metastatic STS of the extremities and trunk wall, any grade, diagnosed between 2008 and 2012, treated with at least neoadjuvant treatment and surgical resection and observed for a minimum of 3 years after diagnosis. The primary objective was to evaluate the effect of pCR. (≤5% viable tumor cells or ≥95% necrosis/fibrosis) on 3y-DFS. Effect on local recurrence-free survival (LRFS), distant recurrence-free survival (MFS) overall survival (OS) at 3 years was also analyzed. Statistical univariate analysis utilized chi-square independence test and odds ratio confidence interval (CI) estimate, multivariate analysis was performed using LASSO. Results: A total of 330 patients (median age 56 years old, range:19–95) treated by preoperative RT (67%), CT (15%) or CRT (18%) followed by surgery were included. pCR was achieved in 74/330 (22%) of patients, of which 56/74 (76%) had received RT. 3-yr DFS was observed in 76% of patients with pCR vs 61% without pCR (p < 0.001). Multivariate analysis showed that pCR is statistically associated with better MFS (95% CI, 1.054–3.417; p = 0.033), LRFS (95% CI, 1.226–5.916; p = 0.014), DFS (95% CI, 1.165–4.040; p = 0.015) and OS at 3 years (95% CI, 1.072–5.210; p = 0.033). Conclusions: In a wide, heterogeneous STS population we showed that pCR to preoperative treatment is prognostic for survival