Langerhans cell histiocytosis is a neoplasm and consequently its recurrence is a relapse: In memory of Bob Arceci

Langerhans cell histiocytosis (LCH) remains a poorly understood disorder with heterogeneous clinical presentations characterized by focal or disseminated lesions that contain excessive CD1a+ langerin+ cells with dendritic cell features known as “LCH cells.” Two of the major questions investigated over the past century have been (i) the origin of LCH cells and (ii) whether LCH is primarily an immune dysregulatory disorder or a neoplasm. Current opinion is that LCH cells are likely to arise from hematopoietic precursor cells, although the stage of derailment and site of transformation remain unclear and may vary in patients with different extent of disease. Over the years, evidence has provided the view that LCH is a neoplasm. The demonstration of clonality of LCH cells, insufficient evidence alone for neoplasia, is now bolstered by finding driver somatic mutations in BRAF in up to 55% of patients with LCH, and activation of the RAS‐RAF‐MEK‐ERK (where MEK and ERK are mitogen‐activated protein kinase and extracellular signal‐regulated kinase, respectively) pathway in nearly 100% of patients with LCH. Herein, we review the evidence that recurrent genetic abnormalities characterized by activating oncogenic mutations should satisfy prerequisites for LCH to be called a neoplasm. As a consequence, recurrent episodes of LCH should be considered relapsed disease rather than disease reactivation. Mapping the complete genetic landscape of this intriguing disease will provide additional support for the conclusion that LCH is a neoplasm and is likely to provide more potential opportunities for molecularly targeted therapies.     

Equilibrium point control cannot be refuted by experimental reconstruction of equilibrium point trajectories

In the literature, it has been hotly debated whether the brain uses internal models or equilibrium point (EP) control to generate arm movements. EP control involves specification of EP trajectories, time series of arm configurations in which internal forces and external forces are in equilibrium; if the arm is not in a specified EP, it is driven toward this EP by muscle forces arising due to central drive, reflexes, and muscle mechanics. EP control has been refuted by researchers claiming that EP trajectories underlying movements of subjects were complex. These researchers used an approach that involves applying force perturbations during movements of subjects and fitting a mass-spring-damper model to the kinematic responses, and then reconstructing the EP trajectory using the estimated stiffness, damping, and measured kinematics. In this study, we examined the validity of this approach using an EP-controlled musculoskeletal model of the arm. We used the latter model to simulate unperturbed and perturbed maximally fast movements and optimized the parameter values of a mass-spring-damper model to make it reproduce as best as possible the kinematic responses. It was shown that estimated stiffness not only depended on the "true" stiffness of the musculoskeletal model but on all of its dynamical parameters. Furthermore it was shown that reconstructed EP trajectories were in agreement with those presented in the literature but did not resemble the simple EP trajectories that had been used to generate the movement of the model. It was concluded that the refutation of EP control on the basis of results obtained with mass-spring-damper models was unjust.     

Do Surrogate Endpoints Better Correlate with Overall Survival in Studies That Did Not Allow for Crossover or Reported Balanced Postprogression Treatments? An Application in Advanced Non–Small Cell Lung Cancer

Background

In previous studies, correlation between overall survival (OS) and surrogate endpoints like objective response rate (ORR) or progression-free survival (PFS) in advanced non-small cell lung cancer (NSCLC) was poor. This can be biased by crossover and postprogression treatments.

Assessing Lung Cancer Screening Programs under Uncertainty in a Heterogeneous Population

Background

Lung cancer screening can reduce cancer mortality. Most implementation studies focus only on low-dose computed tomography (LDCT) and clinical attributes of screening and do not include preferences of potential participants. In this study we evaluated the perceived value of screening programs based on LDCT, breath analysis (BA), or blood biomarkers (BB) according to the perspective of the target population.

Identifying viable theoretical frameworks with essential parameters for real-time and real world alcohol craving research: a systematic review of craving models

Background: Substance use is known to be episodic, dynamic, complex, and highly influenced by the environment, therefore a situational and momentary focus to alcohol craving research is appropriate. Current advances in mobile and wearable technology provide novel opportunities for craving research. However, the lack of consensus within craving theory impedes the identification and prioritization of parameters to be monitored. The aim of this study is to critically review current craving models in order to determine viable theoretical frameworks of alcohol craving and its essential parameters.

Methods: Eighteen models of craving were reviewed by applying a literature search with a five-step strategy that accounted for the momentary nature of craving and included a snowballing search and a key term extraction algorithm. Based on this review, multiple decision criteria were defined upon which to evaluate the models.

Results: Six models for alcohol craving were supported by sufficient empirical research to be eligible. The inferences drawn on these six models resulted in three decision criteria: the model should (1) incorporate negative affect as a predictor of relapse; (2) explain that dependent drinkers have a higher attentional bias towards alcohol cues than nondependent drinkers; (3) incorporate increased risk of relapse with heightened stress levels.

Conclusions: The affective processing model of negative reinforcement, the cognitive processing model, the incentive sensitization theory of addiction and the theory of neural opponent motivation are classified as viable theoretical frameworks, resulting in negative affect and stress as relevant parameters to include in real-time craving monitoring research.     

Non-surgical treatment for adult spinal deformity: results of an intensive combined physical and psychological programme for patients with adult spinal deformity and chronic low back pain—a treatment-based cohort study

Objectives

No evidence-based treatment exists for adult spinal deformity (ASD) patients with chronic low back pain (CLBP). Aim of this study: evaluate a combined physical and psychological programme (CPPP) for ASD patients with CLBP and to compare this with a non-ASD-cohort with CLBP.

Methods

Data were extracted from the database of CLBP-patients for whom surgery is not an option and completed CPPP. Two cohorts were selected: an ASD-cohort (n = 80) based on a Cobb angle of > 10° and a consecutive age- and gender-matched non-ASD-cohort (n = 240). Primary outcome: functional status (Oswestry Disability Index; ODI). Secondary outcomes: pain intensity, self-efficacy and quality of life. Assessments: pre and post treatment, one-month and one-year follow-up (FU). Clinical relevance: minimal important clinical change (MCIC; ODI 10 points), patient acceptable symptom state (PASS; ODI ≤ 22).

Results

Demographics ASD-cohort: 79% female, mean age 50.9 (± 14.1) years, mean CLBP duration 15.5 (± 12.5) years, mean Cobb angle 21.4 (± 9.4)°. Non-ASD-cohort: not significantly different. Both cohorts improved in functional status (F[1,318] = 142.982, p < .001; r = 0.31). The ASD-cohort improved from mean ODI 39.5(± 12.0) at baseline to mean ODI 31.8(± 16.5) at one-year FU. Clinical relevance: 51% of the ASD patients reached MCIC and 33% reached a PASS. An interaction effect is shown between time and both cohorts (F[1,318] = 8.2, p = .004; r = 0.03); however, not clinically relevant. All secondary outcomes: improvement at one-year FU.

Conclusion

This is the first study showing beneficial outcomes of a non-surgical treatment in selected ASD patients with longstanding CLBP. Improvement is shown in functional status, and appeared equivalent to the non-ASD cohort.

Level of Evidence 1

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.