Improved survival in overweight and obese patients with aggressive B-cell lymphoma treated with rituximab-containing chemotherapy for curative intent.

The association between obesity and survival in non-Hodgkin lymphoma is unclear. Using the Ontario Cancer Registry we conducted a retrospective analysis of incident cases of aggressive-histology B-cell lymphoma treated with a rituximab-containing regimen with curative intent between 2008-2016. 6246 patients were included. On multivariable analysis the rate of all-cause mortality was lower for the overweight body mass index (BMI 25-29.9 kg/m2) (HR 0.85; 95%CI 0.77-0.95) and obese BMI (≥30 kg/m2) (HR 0.75; 95%CI 0.67-0.85) groups compared to the normal weight group (18.5-24.9 kg/m2). Binomial logistic regression analysis revealed a lower odds ratio (OR) of admission to hospital during treatment in the overweight (OR 0.84; 95%CI 0.75-0.95) compared to normal weight BMI group. In the largest cohort to date of aggressive-histology B-cell lymphoma patients treated with rituximab, increased BMI is associated with a survival advantage, and the magnitude of this effect increases from overweight to obese BMI.

Chinese and South Asian ethnicity, immigration status, and clinical cancer outcomes in the Ontario Cancer System.

BACKGROUND: In the United States, certain minority groups have been shown to have inferior cancer outcomes compared with the white majority population. However, to the authors' knowledge, the majority of research has not separated ethnicity from immigration status. The objective of the current study was to determine the impact of ethnicity, independent of immigration status, on cancer outcomes in Chinese and South Asian populations in Ontario, Canada. METHODS: The authors conducted a population-based retrospective cohort study using administrative databases in Ontario, Canada. Incident cancer cases were captured in Canadian-born Chinese and South Asian individuals, Chinese and South Asian immigrants, and the general Ontario reference population (non-Chinese/non-South Asian and non-immigrant) between 2000 and 2012. Subjects were followed until death (all-cause and cancer-specific), and Cox proportional hazard models were used to estimate the impact of Chinese and South Asian ethnicity on cancer outcomes after adjusting for explanatory variables. RESULTS: A total of 423,678 cancer cases were identified; at total of 6631 cases were identified in Canadian-born Chinese individuals and 2752 cases in Canadian-born South Asian individuals. After adjustment, the rate of all-cause mortality was lower for Canadian-born Chinese (hazard ratio [HR], 0.829; 95% confidence interval [95% CI], 0.795-0.865), Canadian-born South Asian (HR, 0.856; 95% CI, 0.797-0.919), and Chinese immigrant (recent immigrant: HR, 0.661 [95% CI, 0.610-0.716] and non-recent immigrant: HR, 0.853 [95% CI, 0.803-0.906]) populations compared with the general Ontario population. A similar effect was found for cancer-specific mortality. CONCLUSIONS: Chinese and South Asian ethnic groups appear to have lower cancer mortalities compared with the general Ontario population. After removing the well-documented protective effect of immigration, Chinese and South Asian ethnicities were found to be associated with a cancer survival advantage in Ontario, Canada. Cancer 2018;124:1473-82. © 2018 American Cancer Society.

Excessive Sensitivity to Uncertain Visual Input in L-DOPA-Induced Dyskinesias in Parkinson's Disease: Further Implications for Cerebellar Involvement.

UNLABELLED: When faced with visual uncertainty during motor performance, humans rely more on predictive forward models and proprioception and attribute lesser importance to the ambiguous visual feedback. Though disrupted predictive control is typical of patients with cerebellar disease, sensorimotor deficits associated with the involuntary and often unconscious nature of l-DOPA-induced dyskinesias in Parkinson's disease (PD) suggests dyskinetic subjects may also demonstrate impaired predictive motor control. METHODS: We investigated the motor performance of 9 dyskinetic and 10 non-dyskinetic PD subjects on and off l-DOPA, and of 10 age-matched control subjects, during a large-amplitude, overlearned, visually guided tracking task. Ambiguous visual feedback was introduced by adding "jitter" to a moving target that followed a Lissajous pattern. Root mean square (RMS) tracking error was calculated, and ANOVA, robust multivariate linear regression, and linear dynamical system analyses were used to determine the contribution of speed and ambiguity to tracking performance. RESULTS: Increasing target ambiguity and speed contributed significantly more to the RMS error of dyskinetic subjects off medication. l-DOPA improved the RMS tracking performance of both PD groups. At higher speeds, controls and PDs without dyskinesia were able to effectively de-weight ambiguous visual information. CONCLUSION: PDs' visually guided motor performance degrades with visual jitter and speed of movement to a greater degree compared to age-matched controls. However, there are fundamental differences in PDs with and without dyskinesia: subjects without dyskinesia are generally slow, and less responsive to dynamic changes in motor task requirements, but in PDs with dyskinesia, there was a trade-off between overall performance and inappropriate reliance on ambiguous visual feedback. This is likely associated with functional changes in posterior parietal-ponto-cerebellar pathways.

Dyskinetic Parkinson's disease patients demonstrate motor abnormalities off medication.

The pathophysiology of L-dopa-induced dyskinesias (LIDs) in Parkinson's disease (PD) remains poorly understood. The presence of superimposed LIDs clearly differentiates motor performance of dyskinetic from non-dyskinetic PD subjects when they are on medication, but here, we investigated whether their respective motor performance differs while subjects are off L-dopa medication and LIDs are not apparent. We assessed the motor performance of nine dyskinetic and ten non-dyskinetic PD subjects off L-dopa, and of ten age-matched control subjects, during a visually guided tracking task. As previous studies have suggested that linear dynamical system (LDS) models are useful to assess motor performance in PD in addition to overall tracking error, we used LDS models to assess the damping ratio parameter of motor behavior while controlling for disease severity. While overall tracking error did not significantly differ across groups, dyskinetic PD subjects demonstrated a significantly decreased mean damping ratio compared with control and non-dyskinetic PD subjects. For both groups, greater disease severity significantly predicted a lower damping ratio, but even after controlling for disease severity, the damping ratio for dyskinetic subjects was significantly lower. Our results demonstrate, somewhat counter-intuitively, that motor performance of dyskinetic and non-dyskinetic PD subjects differ, even off L-dopa when no dyskinesias are seen. A decreased damping ratio is indicative of a tendency to overshoot a target during motor performance, similar to the dysmetria found in cerebellar patients. We discuss the possibility of motor abnormalities in dyskinetic PD patients off medication in relation to altered functional cerebellar changes described in PD.

Response to sensory uncertainty in Parkinson's disease: a marker of cerebellar dysfunction?

Motor performance is profoundly influenced by sensory information, yet sensory input can be noisy and uncertain. The basal ganglia and the cerebellum are important in processing sensory uncertainty, as the basal ganglia incorporate the uncertainty of predictive reward cues to reinforce motor programs, and the cerebellum and its connections mitigate the effect of ambiguous sensory input on motor performance through the use of forward models. Although Parkinson's disease (PD) is classically considered a primary disease of the basal ganglia, alterations in cerebellar activation are also observed, which may have consequences for the processing of sensory uncertainty. The aim of this study was to investigate the effect of visual uncertainty on motor performance in 15 PD patients and ten age-matched control subjects. Subjects performed a visually guided tracking task, requiring large-amplitude arm movements, by tracking with their index finger a moving target along a smooth trajectory. To induce visual uncertainty, the target position randomly jittered about the desired trajectory with increasing amplitudes. Tracking error was related to target ambiguity to a significantly greater degree in PD subjects off medication compared with control subjects, indicative of susceptibility to visual uncertainty in PD. l-Dopa partially ameliorated this deficit. We interpret our findings as suggesting an inability of PD subjects to create adequate forward models and/or de-weight less informative visual input. As these computations are normally associated with the cerebellum and connections, we suggest that alterations in normal cerebellar functioning may be a significant contributor to altered motor performance in PD.