Cooperative object transport with a swarm of e-puck robots: robustness and scalability of evolved collective strategies

Cooperative object transport in distributed multi-robot systems requires the coordination and synchronisation of pushing/pulling forces by a group of autonomous robots in order to transport items that cannot be transported by a single agent. The results of this study show that fairly robust and scalable collective transport strategies can be generated by robots equipped with a relatively simple sensory apparatus (i.e. no force sensors and no devices for direct communication). In the experiments described in this paper, homogeneous groups of physical e-puck robots are required to coordinate and synchronise their actions in order to transport a heavy rectangular cuboid object as far as possible from its starting position to an arbitrary direction. The robots are controlled by dynamic neural networks synthesised using evolutionary computation techniques. The best evolved controller demonstrates an effective group transport strategy that is robust to variability in the physical characteristics of the object (i.e. object mass and size of the longest object’s side) and scalable to different group sizes. To run these experiments, we designed, built, and mounted on the robots a new sensor that returns the agents’ displacement on a 2D plane. The study shows that the feedback generated by the robots’ sensors relative to the object’s movement is sufficient to allow the robots to coordinate their efforts and to sustain the transports for an extended period of time. By extensively analysing successful behavioural strategies, we illustrate the nature of the operational mechanisms underpinning the coordination and synchronisation of actions during group transport

Overdiagnosis and overtreatment of early detected prostate cancer

Early detection of prostate cancer is associated with the diagnosis of a considerable proportion of cancers that are indolent, and that will hardly ever become symptomatic during lifetime. Such overdiagnosis should be avoided in all forms of screening because of potential adverse psychological and somatic side effects. The main threat of overdiagnosis is overtreatment of indolent disease. Men with prostate cancer that is likely to be indolent may be offered active surveillance. Evaluation of active surveillance studies and validation of new biological parameters for risk assessment are expected

ctDNA-based detection of molecular residual disease in stage I-III non-small cell lung cancer patients treated with definitive radiotherapy

BackgroundSensitive and reliable biomarkers for early detection of recurrence are needed to improve post-definitive radiation risk stratification, disease management, and outcomes for patients with unresectable early-stage or locally advanced non-small cell lung cancer (NSCLC) who are treated with definitive radiation therapy (RT). This prospective, multistate single-center, cohort study investigated the association of circulating tumor DNA (ctDNA) status with recurrence in patients with unresectable stage I-III NSCLC who underwent definitive RT.MethodsA total of 70 serial plasma samples from 17 NSCLC patients were collected before, during, and after treatment. A personalized, tumor-informed ctDNA assay was used to track a set of up to 16 somatic, single nucleotide variants in the associated patient’s plasma samples.ResultsPre-treatment ctDNA detection rate was 82% (14/17) and varied based on histology and stage. ctDNA was detected in 35% (6/17) of patients at the first post-RT timepoint (median of 1.66 months following the completion of RT), all of whom subsequently developed clinical progression. At this first post-RT time point, patients with ctDNA-positivity had significantly worse progression-free survival (PFS) [hazard ratio (HR): 24.2, p=0.004], and ctDNA-positivity was the only significant prognostic factor associated with PFS (HR: 13.4, p=0.02) in a multivariate analysis. All patients who developed clinical recurrence had detectable ctDNA with an average lead time over radiographic progression of 5.4 months, and post-RT ctDNA positivity was significantly associated with poor PFS (p<0.0001).ConclusionPersonalized, longitudinal ctDNA monitoring can detect recurrence early in patients with unresectable NSCLC patients undergoing curative radiation and potentially risk-stratify patients who might benefit most from treatment intensification

18FDG-PET-Based Assessment of Local Failure Patterns in Non-Small Cell Lung Cancer (NSCLC) Treated with Definitive Radiotherapy

To assess the pattern of local failure using (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) scans after radiotherapy (RT) in non-small-cell lung cancer (NSCLC) patients treated with definitive RT whose gross tumor volumes (GTVs) were defined with the aid of pre-RT PET data. METHOD AND MATERIALS: The data from 26 patients treated with involved-field RT who had local failure and a post-RT PET scan were analyzed. The patterns of failure were visually scored and defined as follows: (1) within the GTV/planning target volume (PTV); (2) within the GTV, PTV, and outward; (3) within the PTV and outward; and (4) outside the PTV. Local failure was also evaluated as originating from nodal areas vs. the primary tumor. RESULTS: We analyzed 34 lesions. All 26 patients had recurrence originating from their primary tumor. Of the 34 lesions, 8 (24%) were in nodal areas, 5 of which (63%) were marginal or geographic misses compared with only 1 (4%) of the 26 primary recurrences (p = 0.001). Of the eight primary tumors that had received a dose of or = 60 Gy, 6 (33%) of 18 had failure within the GTV and 11 (61%) at the GTV margin, and 1 (6%) was a marginal miss (p < 0.05). CONCLUSION: At lower doses, the pattern of recurrences was mostly within the GTV, suggesting that the dose might have been a factor for tumor control. At greater doses, the treatment failures were mostly at the margin of the GTV. This suggests that visual incorporation of PET data for GTV delineation might be inadequate, and more sophisticated approaches of PET registration should be evaluated

Immediate Dental Implants in Fibula Free Flaps to Reconstruct the Mandible: A Pilot Study of the Short-Term Effects on Radiotherapy for Patients with Head and Neck Cancer

OBJECTIVES: The current pilot study aims to report short-term experience as it relates to acute radiotherapy treatment outcomes comparing patients with immediate dental implants in fibula free flap reconstructions to a historical cohort of patients with fibula free flap reconstructions without dental implants. MATERIALS AND METHODS: A retrospective review of patients who underwent segmental mandibulectomy, reconstruction with fibula free flaps, and adjuvant radiotherapy with (n = 10) and without immediate dental implants (n = 10) at a tertiary cancer center from 2015 to 2018 was performed (IRB #17-271). Incidence of postoperative complications, time to initiation of radiation therapy, development of acute toxicity, and patient reported outcome data were recorded. The radiation plans were evaluated to identify the mean and maximum doses received by the mandible and oral cavity as well as the locations of radiation global hot spots. RESULTS: There was a similar number of postoperative complications in both cohorts, with three events in the case group and two events in the control group. Patients with dental implants reported less trismus than control patients. Evaluation of the radiation treatment plans revealed similar median radiation global hot spots in both groups. CONCLUSIONS: The current study suggests that the presence of dental implants does not increase the risk of complications following surgery or during radiation treatment. Implants do not alter radiation dosimetry but do appear to positively impact early patient quality of life. Although longer follow-up is needed, based on this preliminary experience, cancer patients should be offered this type of reconstruction without fear of impacting radiation timing or delivery

PIK3CA mutation is associated with increased local failure in lung stereotactic body radiation therapy (SBRT)

Objectives: Hyperactivation of the phosphatidylinositol-3-kinase (PI3K) pathway has been associated with radioresistance. It is unclear whether such mutations confer suboptimal local control for patients who receive lung stereotactic body radiation therapy (SBRT). Our objective was to examine whether mutations in the EGFR/AKT/PIK3CA signaling pathway are associated with local failure (LF) after lung SBRT. Methods: We retrospectively reviewed 166 patients who underwent SBRT to primary or metastatic lung lesions from 2007 to 2015 for whom genetic testing data was available for EGFR, AKT, and PIK3CA genes. Association between clinical factors, including molecular mutation status, and LF was evaluated. Results: Six patients (4%) had PIK3CA mutation, 36 patients (22%) had EGFR mutation, and one patient (0.6%) had AKT1 mutation. Median lesion size was 2.0â¯cm (range, 0.6â5.6â¯cm); median dose was 48â¯Gy in 4 fractions (range, 30â70â¯Gy in 3â10 fractions). Median follow-up for survivors was 27.3â¯months (range, 3.8â66.7â¯months). LF occurred in 16 patients (10%). On univariate analysis, PIK3CA mutation was associated with LF (HR 10.44 [95% CI 2.16â50.46], pâ¯=â¯.003), while tumor histology, tumor size, primary tumor site, BED and EGFR mutation were not. At one year, probability of LF in lesions with PIK3CA mutation was 20.0% vs. 2.9% in lesions without mutation (pâ¯<â¯.001 by log rank test). Conclusion: Although the number of patients affected was small, PIK3CA mutation was significantly associated with higher risk of LF in patients undergoing lung SBRT. This association has not previously been reported for lung SBRT and indicates the need for further validation. Keywords: Lung stereotactic body radiation therapy (SBRT), PIK3CA, Radiation resistance, Local failur