Socio-Economic Status in Risk of Acute Adverse Events Following Radiotherapy

PURPOSE/OBJECTIVE(S)

Socio-economic status (SES) are known to influence cancer patient outcomes. The purpose of this study is to evaluate whether SES affected the short-term clinical experience of patients treated with radiotherapy (RT) during the pandemic.

MATERIALS/METHODS

This was a single institution, retrospective cohort quality improvement study. The primary endpoint consisted of adverse events (AEs) defined as an unplanned admission to a drop-in radiation-nursing clinic (RNC) or the institution's emergency department (ED) within 90 days of a radiation course. Adult cancer patients who received external beam RT from April 1, 2019, to March 31, 2022 were included. Patients were classified into two periods: treated prior to the pandemic (pre-COVID), and during the pandemic (COVID era), with a cutoff date of March 31, 2020. SES, age, RT intent (curative, palliative, SBRT), regimen (conventional fractionation and hypofractionation), disease site, and sex were included as co-variables. SES was obtained by matching a patient's postal code with a provincial data tool with four distinct dimensions: 1) residential instability, 2) material deprivation, 3) ethnic concentration, and 4) dependency. For each SES dimension, a score of 1-5 (best-worst) is assigned to individuals. A backward stepwise multivariable logistic regression analysis was performed to analyze the variables and identify the factors that were significantly associated (p<0.05) with increased risk of AEs. Institutional ethics review board exemption was obtained.

RESULTS

Across the 3-year period, 15715 patients (5499 pre-COVID and 10216 COVID era patients) were identified and included in the analyses, and 5756 AEs were observed. The analyses revealed that patient age (p<0.001), disease site (p<0.001), treatment intent (p<0.001) and treatment regimen (p = 0.005) were associated with the risk of developing AEs. AEs risk was correlated with the treatment period (pre-COVID vs. COVID era) (p<0.001) and material deprivation (p = 0.027). Adjusting for the other variables, patients who were least materially deprived were at lower risk (Odds Ratio (OR) = 0.88, 95% CI [0.78-0.98]) of developing AEs than patients who were most materially deprived. Patient sex (p>0.1), residential instability (p = 0.069), ethnic concentration (p>0.5) and dependency (p>0.5) were not associated with AEs risk. Patients with more (SES score 1-4 vs 5) residential instability (p<0.001; OR = 0.82, 95% CI [0.74-0.90]) and less (SES score 1 vs 2-5) material deprivations (p = 0.006; OR = 0.76, 95% CI [0.66-0.88]) were at reduced the risk of ED visits. SES was not associated with RNC visits.

CONCLUSION

In a universal health care system, SES (residential instability and material deprivation) were associated with the increased risk of ED within 90 days of RT. Proactive care and virtual monitoring during the 90-day period after RT in high-risk patients may reduce ED visits. ED visits beyond our tertiary institution are being gathered to address this study limitation.

Rural-Urban Differences in Vaccination and Hesitancy Rates and Trust: US COVID-19 Trends and Impact Survey on a Social Media Platform, May 2021-April 2022

Objectives. To analyze rural-urban differences in COVID-19 vaccination uptake, hesitancy, and trust in information sources in the United States. Methods. We used data from a large survey of Facebook users. We computed the vaccination, hesitancy, and decline rates and the trust proportions among individuals hesitant toward COVID-19 information sources for rural and urban regions in each state from May 2021 to April 2022. Results. In 48 states with adequate data, on average, two thirds of states showed statistically significant differences in monthly vaccination rates between rural and urban regions, with rural regions having a lower vaccination rate at all times. Far fewer states showed statistically significant differences when comparing monthly hesitancy and decline rates for urban versus rural regions. Doctors and health professionals received the highest level of trust. Friends and family were also among the most trusted sources in rural areas where the vaccination uptake was low. Conclusions. Rural-urban difference in hesitancy rates among those still unvaccinated was much smaller than the rural-urban difference in vaccination rates, suggesting that access to vaccines may be another contributor to the lower vaccination rates in rural areas. (Am J Public Health. Published online ahead of print April 13, 2023:e1-e9. https://doi.org/10.2105/AJPH.2023.307274).

Evaluating the Short-Term Environmental and Clinical Effects of a Radiation Oncology Department's Response to the COVID-19 Pandemic (STEER COVID-19)

Purpose/Objective(s)

During the COVID-19 pandemic, hypofractionated regimens and virtual care was adopted by our institution to preserve hospital capacity and reduce foot traffic. This study's primary objective was to assess the collective environmental impact of these strategic changes by identifying sources of carbon dioxide equivalents (CO₂e). As sustainable healthcare is only justifiable if the quality of the care is maintained, we also evaluated the rate of radiation-related acute adverse event.

Materials/Methods

All patients treated with external beam radiation therapy from April 1, 2019 to March 31, 2021 at our single institution were identified (n=10,175) along with their radiotherapy visits (176,423 fractions), and visits to the radiation nursing clinic (RNC) or emergency (ER) department. A treatment regimen was considered hypofractionated if the dose per fraction was ≥ 240 cGy. If the dose per fraction was ≥ 600 cGy and the total dose of the treatment regimen was > 2000 cGy, then the treatment regimen was classified as SBRT. Out-patient hospital and virtual visits (n=75,853) during this same period were also analyzed. Environmental impact measures, including linear accelerator power usage, patient travel distances, and personal protection equipment (PPE) consumption were all converted into CO₂e. A waiver of individual patient consent was granted for this study by our institution's Research Ethics Board (REB).

Results

The use of curative hypofractionated regimens increased from 17% to 27% during the pandemic year. Twelve out of 15 cancer sites increased their use of hypofractionated regimens. Carbon footprint was reduced by 39% during the pandemic year (1,332,388 kg CO₂e) as compared to the pre-pandemic year (2,024,823 kg CO₂e). For comparison, the 744 tonnes of CO₂e saved during the pandemic year equates to the CO₂e produced by the annual energy consumption of 182 Canadian households or the CO₂e sequestered by 12,000 seedling trees planted and grown for 10 years. On average 121 kg CO₂e and 100 kg CO₂e were emitted per radiation regimen delivered during the pre-pandemic and pandemic year, respectively. Comparing patients in the pre-pandemic vs. pandemic year, there was a significant reduction in the proportion of hypofractionated patients who needed a visit to either the RNC (39% vs. 25%; p<0.001) or ER (6% vs. 2%; p<0.001) during and within 90 days of radiotherapy.

Conclusion

This study demonstrated the environmental benefits of increased use of hypofractionated regimens and virtual care, while assuring that there was no added acute radiation-related adverse event. Our findings support their continued use as one of many long-term strategies to reduce the environmental footprint of healthcare delivery. Treatment efficacy and side-effects will need to be assessed in subsequent years to further support the sustainability of these strategies.

Prevalence, characteristics and mortality outcomes of obese, nonobese and lean NAFLD in the United States, 1999-2016

BACKGROUND

Updated prevalence and outcome data for nonobese NAFLD for the multi-ethnic US population is limited.

OBJECTIVES

We aimed to investigate the prevalence, clinical characteristics and mortality of obese and nonobese individuals with NAFLD in the United Sates.

METHODS

A retrospective study was conducted using the 1999-2016 NHANES databases. We determined hazard ratio stratified by obesity status in NAFLD individuals using Cox regression and log-rank test.

RESULTS

Overall NAFLD prevalence was 32.3%: 22.7% were obese and 9.6% were nonobese, with increasing trend over time for obese NAFLD, but not nonobese NAFLD. Amongst those with NAFLD, 29.7% (95% CI: 27.8%-31.7%) were nonobese, of which 13.6% had lean NAFLD. Nonobese NAFLD was more common in older (40.9% if ≥ 65 vs. 24.2% if < 65 years), male (34.0% vs. 24.2%) and foreign-born Asian people (39.8% vs. 11.4%) and uncommon in black (11.5% vs 30-35% in other ethnicities, P < 0.001). Metabolic comorbidities were common in nonobese NAFLD individuals who also had more advanced fibrosis. Nonobese NAFLD individuals had higher 15-year cumulative all-cause mortality (51.7%) than obese NAFLD (27.2%) and non-NAFLD (20.7%) (P < 0.001). However, DM and fibrosis, but neither obese nor nonobese NAFLD compared to non-NAFLD was independently associated with higher mortality.

CONCLUSION

Nonobese NAFLD makes up about one-third of the NAFLD in the United States (even higher in older, male and foreign-born individuals) and carries higher mortality than obese NAFLD. Screening for NAFLD should be considered in high-risk groups even in the absence of obesity.

Ethnic influence on nonalcoholic fatty liver disease prevalence and lack of disease awareness in the United States, 2011-2016

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a rising global disease associated with clinical and economic burdens.

OBJECTIVES

We aimed to quantify NAFLD prevalence and awareness to provide stakeholders necessary information to combat NAFLD burden.

METHODS

This study utilizes data from the National Health and Nutrition Examination Survey 2011-2016 and included 4538 adult participants who did not have heavy drinking or viral hepatitis history. The US fatty liver index defined NAFLD and NAFLD fibrosis score defined fibrosis. NAFLD awareness was captured by questionnaire.

RESULTS

Amongst the study population of 4538 persons, NAFLD prevalence was 32.5%, lowest in non-Hispanic Blacks (18.0%) and Asians (18.1%), highest amongst Mexican Americans (48.4%). Within the NAFLD group, advanced fibrosis was highest in non-Hispanic Blacks (28.5%) and lowest amongst non-Hispanic Asians (2.7%). Of the 1473 (97.5%) NAFLD participants who answered NAFLD awareness question, 90% visited a healthcare centre at least once in the past year, but only 5.1% were aware of having NAFLD. On weighted population estimates, 77.33 million persons had NAFLD, 17.63 million had advanced fibrosis, and 73.39 million NAFLD participants were not aware of having NAFLD.

CONCLUSIONS

Of 77.33 million people in the United States have NAFLD with 17.63 million having advanced fibrosis, with lowest prevalence in non-Hispanic Asians and highest in Mexican Americans. A conundrum exists amongst non-Hispanic Blacks who have low NAFLD prevalence but highest prevalence of advanced fibrosis. Awareness of NAFLD was low across all ethnicities. Effort is needed to improve disease awareness whilst addressing NAFLD clinical burden across ethnicities.

The 2014 Survey on Living with Chronic Diseases in Canada on Mood and Anxiety Disorders: a methodological overview

INTRODUCTION

There is a paucity of information about the impact of mood and anxiety disorders on Canadians and the approaches used to manage them. To address this gap, the 2014 Survey on Living with Chronic Diseases in Canada-Mood and Anxiety Disorders Component (SLCDC-MA) was developed. The purpose of this paper is to describe the methodology of the 2014 SLCDC-MA and examine the sociodemographic characteristics of the final sample.

METHODS

The 2014 SLCDC-MA is a cross-sectional follow-up survey that includes Canadians from the 10 provinces aged 18 years and older with mood and/or anxiety disorders diagnosed by a health professional that are expected to last, or have already lasted, six months or more. The survey was developed by the Public Health Agency of Canada (PHAC) through an iterative, consultative process with Statistics Canada and external experts. Statistics Canada performed content testing, designed the sampling frame and strategies and collected and processed the data. PHAC used descriptive analyses to describe the respondents' sociodemographic characteristics, produced nationally representative estimates using survey weights provided by Statistics Canada, and generated variance estimates using bootstrap methodology.

RESULTS

The final 2014 SLCDC-MA sample consists of a total of 3361 respondents (68.9% response rate). Among Canadian adults with mood and/or anxiety disorders, close to twothirds (64%) were female, over half (56%) were married/in a common-law relationship and 60% obtained a post-secondary education. Most were young or middle-aged (85%), Canadian born (88%), of non-Aboriginal status (95%), and resided in an urban setting (82%). Household income was fairly evenly distributed between the adequacy quintiles; however, individuals were more likely to report a household income adequacy within the lowest (23%) versus highest (17%) quintile. Forty-five percent reported having a mood disorder only, 24% an anxiety disorder only and 31% both kinds of disorder.

CONCLUSION

The 2014 SLCDC-MA is the only national household survey to collect information on the experiences of Canadians living with a professionally diagnosed mood and/or anxiety disorder. The information collected offers insights into areas where additional support or interventions may be needed and provides baseline information for future public health research in the area of mental illness.

Analysis of SEER Glassy Cell Carcinoma Data: Underuse of Radiotherapy and Predicators of Cause Specific Survival

BACKGROUND

This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) for glassy cell carcinoma data to identify predictive models and potential disparities in outcome.

MATERIALS AND METHODS

This study analyzed socio-economic, staging and treatment factors. For risk modeling, each factor was fitted by a generalized linear model to predict the cause specific survival. Area under the receiver operating characteristic curves (ROCs) were computed. Similar strata were combined to construct the most parsimonious models. A random sampling algorithm was used to estimate modeling errors. Risk of glassy cell carcinoma death was computed for the predictors for comparison.

RESULTS

There were 79 patients included in this study. The mean follow up time (S.D.) was 37 (32.8) months. Female patients outnumbered males 4:1. The mean (S.D.) age was 54.4 (19.8) years. SEER stage was the most predictive factor of outcome (ROC area of 0.69). The risks of cause specific death were, respectively, 9.4% for localized, 16.7% for regional, 35% for the un-staged/others category, and 60% for distant disease. After optimization, separation between the regional and unstaged/others category was removed with a higher ROC area of 0.72. Several socio-economic factors had small but measurable effects on outcome. Radiotherapy had not been used in 90% of patients with regional disease.

CONCLUSIONS

Optimized SEER stage was predictive and useful in treatment selection. Underuse of radiotherapy may have contributed to poor outcome.

Analysis of SEER Adenosquamous Carcinoma Data to Identify Cause Specific Survival Predictors and Socioeconomic Disparities

BACKGROUND

This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) adenosquamous carcinoma data to identify predictive models and potential disparities in outcome.

MATERIALS AND METHODS

This study analyzed socio-economic, staging and treatment factors available in the SEER database for adenosquamous carcinoma. For the risk modeling, each factor was fitted by a generalized linear model to predict the cause specific survival. An area under the receiver operating characteristic curve (ROC) was computed. Similar strata were combined to construct the most parsimonious models.

RESULTS

A total of 20,712 patients diagnosed from 1973 to 2009 were included in this study. The mean follow up time (S.D.) was 54.2 (78.4) months. Some 2/3 of the patients were female. The mean (S.D.) age was 63 (13.8) years. SEER stage was the most predictive factor of outcome (ROC area of 0.71). 13.9% of the patients were un-staged and had risk of cause specific death of 61.3% that was higher than the 45.3% risk for the regional disease and lower than the 70.3% for metastatic disease. Sex, site, radiotherapy, and surgery had ROC areas of about 0.55-0.65. Rural residence and race contributed to socioeconomic disparity for treatment outcome. Radiotherapy was underused even with localized and regional stages when the intent was curative. This under use was most pronounced in older patients.

CONCLUSIONS

Anatomic stage was predictive and useful in treatment selection. Under-staging may have contributed to poor outcome.

2-Chloroacetamidine, a novel immunomodulator, suppresses antigen-induced mouse airway inflammation

BACKGROUND

Citrullination is a presently under-recognized posttranslational protein modification catalyzed by PAD enzymes. Immune responses to citrullinated neo-epitopes are identified in a growing number of inflammatory and autoimmune diseases. However, the involvement of hypercitrullination in the pathogenesis of bronchial asthma is still unknown.

METHODS

As main experimental tool, we examined the effect of 2-chloroacetamidine (2CA), a PAD enzyme inhibitor, on OVA-immunized and airway-challenged BALB/c mice; a commonly used model of allergic airway inflammation. We also measured the effect of 2CA on ex vivo lymphocytes and cell lines.

RESULTS

In vivo, 2CA dramatically suppressed lung tissue hypercitrullination, inflammatory cell recruitment, and airway-Th2 cytokine secretion. 2CA also suppressed systemic OVA-specific and total IgE production dramatically, effectively preventing de novo and diminishing established disease without measurably impacting general immunocompetence. In vitro, 2CA markedly inhibited the proliferation of mouse and human T cells with cell cycle block and apoptosis during a limited, postactivation phase.

CONCLUSIONS

2CA acts as narrow-spectrum immunosuppressant that selectively targets lymphocyte populations involved in active inflammatory tissue lesions. If hypercitrullination is generated in patients with asthma, 2CA may represent a novel disease modulator for human asthmatics/allergic diseases.

Comparative effectiveness of the hepatitis C virus protease inhibitors boceprevir and telaprevir in a large U.S. cohort

BACKGROUND

Limited data exist on the effectiveness of boceprevir and telaprevir in routine practice.

AIM

To assess the comparative effectiveness of boceprevir and telaprevir regimens.

METHODS

In this observational, intent-to-treat cohort analysis of hepatitis C genotype 1-infected veterans initiated on peginterferon/ribavirin and boceprevir (n = 661) or telaprevir (n = 198), we determined sustained virological response (SVR), treatment discontinuation rates and adverse haematological events. Inverse probability-of-treatment weighting (IPTW) was used to estimate the effect of one drug over the other, with matched pairs and unweighted logistic regression on the entire cohort for comparison.

RESULTS

Of 835 veterans, SVR occurred in 50% and 52% receiving boceprevir- and telaprevir-based treatment, respectively (P = 0.72). No significant differences occurred among subgroups: cirrhotics (37% vs. 39%, P = 0.94), null responders (23% vs. 18%, P = 0.81), partial responders (39% vs. 58%, P = 0.15) and relapsers (60% vs. 77%, P = 0.11). Early discontinuation rates for boceprevir and telaprevir, respectively, were 31% and 28% by week 24 (P = 0.46) and 54% and 45% by 48 weeks (in those completing at least 28 weeks) (P = 0.14). Choice of telaprevir over boceprevir was significantly associated with SVR in multivariate models (IPTW OR: 1.57, 95% CI: 1.10-2.25, P = 0.01; matched-pairs OR: 1.91, 95% CI: 1.23-3.00, P = 0.004; unweighted OR: 1.50 95% CI: 1.05-2.14, P = 0.02). Rates of haematological adverse events in boceprevir- and telaprevir-treated patients were as follows: anaemia 59% vs. 51%, P = 0.30, thrombocytopenia 41% vs. 48%, P = 0.26, neutropenia 41% vs. 27%, P = 0.04.

CONCLUSIONS

Sustained virological response was more likely with telaprevir-based regimens compared with boceprevir-based regimens in routine medical practice, after accounting for patient differences. Early discontinuation and haematological events, however, were similar.

Poor treatment outcome of neuroblastoma and other peripheral nerve cell tumors may be related to under usage of radiotherapy and socio-economic disparity: a US SEER data analysis

PURPOSE

This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) neuroblastoma (NB) and other peripheral nerve cell tumors (PNCT) outcome data. This study found under usage of radiotherapy in these patients.

MATERIALS AND METHODS

This study analyzed socio-economic, staging and treatment factors available in the SEER database for NB and other PNCT. For the risk modeling, each factor was fitted by a generalized jinear model to predict the outcome (soft tissue specific death, yes/no). The area under the receiver operating characteristic curve (ROC) was computed. Similar strata were combined to construct the most parsimonious models. A random sampling algorithm was used to estimate the modeling errors. Risk of neuroendocrine (other endocrine including thymus as coded in SEER) death was computed for the predictors.

RESULTS

There were 5261 patients diagnosed from 1973 to 2009 were included in this study. The mean follow up time (S.D.) was 83.8 (97.6) months. The mean (SD) age was 18 (25) years. About 30.45% of patients were un-staged. The SEER staging has high ROC (SD) area of 0.58 (0.01) among the factors tested. We simplified the 4-layered risk levels (local, regional, distant, un-staged/others) to a simpler 3-tiered model with comparable ROC area of 0.59 (0.01). Less than 50% of PNCT patients received radiotherapy (RT) including the ones with localized disease. This avoidance of RT use occurred in adults and children.

CONCLUSION

The high under-staging rate may have prevented patients from selecting definitive radiotherapy (RT) after surgery. Using RT for, especially, adult PNCT patients is a potential way to improve outcome.

Impact of socioeconomic disparities on cause-specific survival of retinoblastoma

Retinoblastoma (RB) is a rare disease of infancy and early childhood. This study investigated the effects of socioeconomic factors on the cause-specific survival of RB. Data from patients diagnosed with RB between 1973 and 2009 were obtained from the Surveillance, Epidemiology and End Results (SEER) database. The study included 1,456 patients with a the mean follow-up time (SD) of 128.75 (113.74) months and a mean age (SD) of 1.4 (2.6) years. This study analyzed socioeconomic, staging and treatment factors available in the SEER database for RB. Kaplan-Meier analysis was used to analyze time-to-failure data. The two-sample Kolmogorov-Smirnov test was used for univariate analysis and the Cox proportional hazards model was used for multivariate analysis. The area under the receiver operating characteristic (ROC) curve was computed for predictors. SEER stage was the most significant predictive pretreatment factor. The identified socioeconomic barriers included ethnicity and rural-urban residence status that led to a 3% decrease in RB cause-specific survival. Thus, eliminating barriers to treatment is crucial for reducing the outcome disparities.

The water exchange method for colonoscopy-effect of coaching

The growing popularity of water immersion is supported by its long history as an adjunct to air insufflation; after facilitating colonoscope passage, the infused water is conveniently removed during withdrawal. Water exchange, a modification of water immersion to minimize discomfort in scheduled unsedated patients in the U.S. is new. Even though it may be superior in reducing pain and increasing adenoma detection, the paradigm shift to complete exclusion of air during insertion necessitates removal of infused water containing residual feces, a step often perceived as laborious and time-consuming. The nuances are the efficient steps to remove infused water predominantly during insertion to maintain minimal distension and deliver salvage cleansing. Mastery of the novel maneuvers with practice returns insertion time towards baseline. In this observational study the impact of direct verbal coaching on the primary outcome of intention-to-treat cecal intubation was assessed. The results showed that 14 of 19 (74%) experienced colonoscopists achieved 100% intention-to-treat cecal intubation. Initiation of the examination with water exchange did not preclude completion when conversion to the more familiar air insufflation method was deemed necessary to achieve cecal intubation (total 98%). The overall intention-to-treat cecal intubation rate was 88%, 90% in male and 87% in female. Only 2.7% of bowel preparation was rated as poor during withdrawal. The mean volume of water infused and cecal intubation time was 1558 ml and 18 min, respectively. Direct coaching appears to facilitate understanding of the nuances of the water exchange method. Studies of individual learning curves are necessary.

Implications of rapid virological response in hepatitis C therapy in the US veteran population

BACKGROUND

Early predictors of response to hepatitis C virus (HCV) therapy, such as rapid virological response, are valuable for the identification of patients with a higher likelihood of treatment success.

AIM

To identify predictors of rapid virological response in a real world setting.

METHODS

Using the VA Clinical Case Registry, we identified patients with HCV mono-infection, without liver transplantation, who initiated peginterferon (PEG-IFN) and ribavirin (RBV) in 2007 or 2008 and had HCV RNA testing for RVR. Significant baseline characteristics from genotype specific univariate analyses were used in backwards stepwise models to identify significant independent predictors of RVR.

RESULTS

The final cohort consisted of 2424 patients with genotype 1 (G1), 666 patients with genotype 2 (G2), and 419 patients with genotype 3 (G3). Rapid virological response rates were 15% for G1, 71% for G2 and 57% for G3. Sustained virological response rates were significantly higher in patients with rapid virological response than without, increasing from 18% to 52% in G1, 39% to 71% in G2, and 40% to 60% in G3 (P < 0.0001). A baseline HCV RNA < 500,000 IU/mL positively predicted RVR across all genotypes studied. In addition, for G1, Black race, Hispanic ethnicity, aspartate aminotransferase/alanine aminotransferase (AST/ALT) ≥ 0.6, ferritin ≥ 350 ng/mL, LDL< 100 mg/dL and diabetes; for G2, BMI ≥ 30 kg/m(2), platelets < 150 K/μL, LDL< 100 mg/dL and the use of PEG-IFN alfa-2b; and for G3, AST/ALT ≥ 1.0, all negatively predicted rapid virological response.

CONCLUSION

We found several novel independent predictors of rapid virological response, including BMI, AST/ALT ratio, ferritin, platelets, LDL, diabetes and type of PEG-IFN prescribed, which may be useful in guiding treatment decisions in routine medical practice.

Effects of Confinement on Plastic Deformation in Passivated Al Films

Wafer curvature measurements of a trilayer (SiO2 / AlSiCu / Si) structure are compared to that predicted by a weighted sum of individual measurements of SiO2 and AISiCu films on Si, and significant differences are found to exist for temperatures above 200°C. A straightforward analysis of the stresses in each layer has been modeled using an extension of a model by Feng et al. which assumes uniform plastic deformation throughout the Al. The modeling results suggest a straightforeward method for determining stresses in deformable thin films that are confined by elastic overlayers. A comparison of the stress-temperature behavior for unpassivated and passivated AISiCu films reveals that the confined films exhibit less plastic deformation and both higher tension and compression during thermal cycling.

Study of the dispersion and electrical properties of carbon nanotubes treated by surfactants in dimethylacetamide

In this study, the effects of sodium dodecyl benzene sulfonate, polyvinylpyrrolidone, sodium dodecyl benzene sulfonate/polyvinylpyrrolidone, and Triton X-100 on the dispersion of 0.1 wt% carbon nanotubes in dimethylacetamide are reported. Sedimentation results show that except for sodium dodecyl benzene sulfonate, all the surfactant-assisted carbon nanotube solutions have visually-stable dispersions for at least two months, and even the samples without a surfactant gave no obvious deposition. UV-Vis spectra of the dispersions with and without acid-treatment proved that the carboxyl group attached to the carbon nanotubes positively improves the dispersion effect. The states of aggregation of carbon nanotubes treated by different surfactants are distinctive, and the electrical properties of carbon nanotubes are strongly related to these states of aggregation. The best dispersing and stabilizing effect was found in the sodium dodecyl benzene sulfonate/polyvinylpyrrolidone sample, which also gave the lowest resistance (2.15 x 10(4) omega at 20 V) among all the surfactant-treated stable suspensions.

A phase I/II dose-escalation trial of vitamin D3 and calcium in multiple sclerosis

OBJECTIVE

Low vitamin D status has been associated with multiple sclerosis (MS) prevalence and risk, but the therapeutic potential of vitamin D in established MS has not been explored. Our aim was to assess the tolerability of high-dose oral vitamin D and its impact on biochemical, immunologic, and clinical outcomes in patients with MS prospectively.

METHODS

An open-label randomized prospective controlled 52-week trial matched patients with MS for demographic and disease characteristics, with randomization to treatment or control groups. Treatment patients received escalating vitamin D doses up to 40,000 IU/day over 28 weeks to raise serum 25-hydroxyvitamin D [25(OH)D] rapidly and assess tolerability, followed by 10,000 IU/day (12 weeks), and further downtitrated to 0 IU/day. Calcium (1,200 mg/day) was given throughout the trial. Primary endpoints were mean change in serum calcium at each vitamin D dose and a comparison of serum calcium between groups. Secondary endpoints included 25(OH)D and other biochemical measures, immunologic biomarkers, relapse events, and Expanded Disability Status Scale (EDSS) score.

RESULTS

Forty-nine patients (25 treatment, 24 control) were enrolled [mean age 40.5 years, EDSS 1.34, and 25(OH)D 78 nmol/L]. All calcium-related measures within and between groups were normal. Despite a mean peak 25(OH)D of 413 nmol/L, no significant adverse events occurred. Although there may have been confounding variables in clinical outcomes, treatment group patients appeared to have fewer relapse events and a persistent reduction in T-cell proliferation compared to controls.

CONCLUSIONS

High-dose vitamin D (approximately 10,000 IU/day) in multiple sclerosis is safe, with evidence of immunomodulatory effects.

CLASSIFICATION OF EVIDENCE

This trial provides Class II evidence that high-dose vitamin D use for 52 weeks in patients with multiple sclerosis does not significantly increase serum calcium levels when compared to patients not on high-dose supplementation. The trial, however, lacked statistical precision and the design requirements to adequately assess changes in clinical disease measures (relapses and Expanded Disability Status Scale scores), providing only Class level IV evidence for these outcomes.

VITATOPS, the VITAmins TO prevent stroke trial: rationale and design of a randomised trial of B-vitamin therapy in patients with recent transient ischaemic attack or stroke (NCT00097669) (ISRCTN74743444)

BACKGROUND

Epidemiological studies suggest that raised plasma concentrations of total homocysteine (tHcy) may be a common, causal and treatable risk factor for atherothromboembolic ischaemic stroke, dementia and depression. Although tHcy can be lowered effectively with small doses of folic acid, vitamin B(12) and vitamin B(6), it is not known whether lowering tHcy, by means of B vitamin therapy, can prevent stroke and other major atherothromboembolic vascular events.

AIM

To determine whether the addition of B-vitamin supplements (folic acid 2 mg, B(6) 25 mg, B(12) 500 microg) to best medical and surgical management will reduce the combined incidence of stroke, myocardial infarction (MI) and vascular death in patients with recent stroke or transient ischaemic attack (TIA) of the brain or eye.

DESIGN

A prospective, international, multicentre, randomised, double blind, placebo-controlled clinical trial.

SETTING

One hundred and four medical centres in 20 countries on five continents.

SUBJECTS

Eight thousand (6600 recruited as of 5 January, 2006) patients with recent (<7 months) stroke (ischaemic or haemorrhagic) or TIA (brain or eye).

RANDOMISATION

Randomisation and data collection are performed by means of a central telephone service or secure internet site.

INTERVENTION

One tablet daily of either placebo or B vitamins (folic acid 2 mg, B(6) 25 mg, B(12) 500 mug).

PRIMARY OUTCOME

The composite of stroke, MI or death from any vascular cause, whichever occurs first. Outcome and serious adverse events are adjudicated blinded to treatment allocation.

SECONDARY OUTCOMES

TIA, unstable angina, revascularisation procedures, dementia, depression. STATISTICAL POWER: With 8000 patients followed up for a median of 2 years and an annual incidence of the primary outcome of 8% among patients assigned placebo, the study will have at least 80% power to detect a relative reduction of 15% in the incidence of the primary outcome among patients assigned B vitamins (to 6.8%/year), applying a two-tailed level of significance of 5%.

CONCLUSION

VITATOPS aims to recruit and follow-up 8000 patients between 1998 and 2008, and provide a reliable estimate of the safety and effectiveness of folic acid, vitamin B(12), and vitamin B(6) supplementation in reducing recurrent serious vascular events among a wide range of patients with TIA and stroke throughout the world.

Persistence with hepatitis C therapy in the Department of Veterans Affairs

BACKGROUND

Persistence with Hepatitis C therapy has been identified as a key variable for predicting treatment success. The primary purpose of this study was to assess the persistence with therapy for patients undergoing hepatitis C treatment in the VA healthcare system with two forms of combination therapies: peginterferon alfa-2a with Ribavirin (peg-IFN alpha-2a/Rib) and peginterferon alpha-2b with Ribavirin (peg-IFN alpha-2b/Rib).

METHODS

A retrospective cohort study design was used to analyse persistence in VA patients undergoing hepatitis C therapy during FY 2003-2004 using a large national VA data set. Stringent inclusion and exclusion criteria along with various defining variables were used to identify the inception cohort. Persistence rates were calculated for each of the two treatment groups at 3, 6, 9 and 11 months using the Kaplan-Meier method. Likelihood ratio test of equality between the two treatment groups was performed to detect any differences in persistence rates.

RESULTS

A total of 5816 hepatitis C patients formed the inception cohort. Persistence rates for the overall duration showed significantly higher rates for patients on peg-IFN alpha-2a/Rib than peg-IFN alpha-2b/Rib. Cox regression analysis also showed favourable hazard ratio of persistence (0.88) for peg-IFN alpha-2a/Rib over peg-IFN alpha-2b/Rib.

CONCLUSION

Peg alfa-2A/Rib showed slightly higher persistence rates for the overall duration of treatment as compared to Peg alfa-2B/Rib. However the differences, even though statistically significant, are small and not likely to translate into any substantial clinical advantage. Further research involving other approaches is required to confirm these findings.

Intravenous Parecoxib Rapidly Leads to COX-2 Inhibitory Concentration of Valdecoxib in the Central Nervous System

Evidence in animal studies supports widespread induction of cyclooxygenase-2 (COX-2) in the central nervous system (CNS) following tissue injury, probably mediated by cytokines, transducing the signal across the blood-brain barrier. CNS COX-2 blockade is a possible therapeutic target for drugs that are able to reach adequate CNS levels and abolish the prostaglandin E2-induced central sensitization. This human pharmacokinetic study investigated valdecoxib cerebrospinal fluid (CSF) and plasma concentrations over time in 37 patients following 40 mg of single-dose intravenous parecoxib. High-performance liquid chromatography/tandem mass spectrometry analysis was performed. Valdecoxib was first detectable in the CSF at 15 min postdosing, increased rapidly until 50 min, and thereafter remained between 6 and 14 ng/ml. This is the first human study demonstrating CNS COX-2 inhibitor penetration as early as 15 min. CSF valdecoxib concentration rapidly reached in vitro IC50 (inhibitory concentration 50) (1.57 ng/ml) by 17 min and remained consistently higher thereafter.

Using a priori structural information from magnetic resonance imaging to investigate the feasibility of prostate diffuse optical tomography and spectroscopy: a simulation study

Implementation of diffuse optical tomography (DOT) for prostate cancer is challenging because the prostate is a deep-seated organ. We investigated whether diffuse optical tomography (DOT) and spectroscopy could be applied to monitor the physiology of prostate cancer using a small probe that could be placed endorectally. We manually segmented the prostate, the intraprostatic tumor, and the rectum using data from endorectal magnetic resonance imaging. These structures were reconstructed and meshed with tetrahedral finite elements in three dimensions. A 2 x 4 cm probe that has ten sources and 52 detectors were placed to face the anterior wall of the rectum in our simulation. Optical properties of the organs were obtained from the literature in the near infrared regime. Diffusion approximation was used to simulate photon migration with finite element method. Five wavelengths were used to simulate tissue absorption with realistic water, oxy- and deoxyhaemoglobin concentrations in the prostate. We combined a global search based on genetic algorithm with gradient-driven local search methods to fit the simulated data. Our results suggest that the optical properties and the concentrations of the chromophores of the prostate and the prostate cancer can be reliably recovered from the measurements using an endorectal probe. Prostate DOT is worth further investigation for clinical application.

Dosimetric comparison of four target alignment methods for prostate cancer radiotherapy

PURPOSE

The aim of this study was to compare the dosimetric consequences of 4 treatment delivery techniques for prostate cancer patients treated with intensity-modulated radiotherapy (IMRT).

METHODS AND MATERIALS

During an 8-week course of radiotherapy, 10 patients underwent computed tomography (CT) scans 3 times per week (243 total) before daily treatment with a CT-linear accelerator. Treatment delivery was simulated by realigning a fixed-margin treatment plan on each CT scan and calculating doses. The alignment methods were those based on the following: skin marks, bony registration, ultrasonography (US), and in-room CT. For the last two methods, prostate was the alignment target. The dosimetric effects of these alignment methods on the prostate, seminal vesicles, rectum, and bladder were compared. The average daily minimum dose to 0.1 cm3 was used as the metric for target coverage.

RESULTS

Skin and bone alignments provided acceptable prostate coverage for only 70% of patients, US alignment for 90%, and CT alignment for 100%. CT-based alignment of the prostate provided seminal vesicle (SV) coverage of > or = 69 Gy for all patients; US and bone alignments provided SV coverage of > or = 60 Gy. This SV coverage may be acceptable for early-stage cancer (equivalent SV dose = 55.8 Gy at 1.8 Gy per fraction), but unacceptable for late-stage cancer (SV dose = 75.6 Gy). At 75.6 Gy, the acceptable rate for SV coverage was 40% for skin and bone alignments, 70% for US, and 80% for CT.

CONCLUSIONS

Direct target alignment methods (US and CT) provided better target coverage. CT-guided alignment provided the best and most consistent dosimetric coverage. A larger planning target volume margin is needed for SV coverage when the alignment target is the prostate.

First-year PSA kinetics and minima after prostate cancer radiotherapy are predictive of overall survival

PURPOSE

We analyzed whether first-year prostate-specific antigen (PSA) kinetics and minima are predictive of overall survival (OS).

METHODS AND MATERIALS

The data set contained 1,174 patients treated with external beam radiotherapy (RT) from 1987 to 2001. The relative rate of change (lambda) in post-RT PSA values during the first year (13.5 months) was computed using regression analysis of ln(PSA) vs. time. We also computed the PSA minimum (mPSA) reached during the same period. Recursive partitioning analysis was used to identify the relevant cutpoints for the factors being investigated for its association with survival: age, pretreatment PSA, radiation dose, relative rate of change in PSA post-RT, and 1-year PSA minimum. For each of the other factors stage, Gleason score and risk group, all possible cutpoints were considered in the multivariate analyses. Significant factors were considered in the multivariate analyses to identify independent predictors for overall survival.

RESULTS

The median value of lambda was -1.0 years(-1) (range, -11.0-5.1 years(-1)). The 1-year minimum had a median of 0.8 ng/mL (range, 0.01-30.9 ng/mL). Recursive partitioning analysis and Cox proportional hazards analyses identified the following pretreatment or treatment factors adversely related to OS: age, Gleason score, stage, and dose. First-year mPSA > or = 4 ng/mL and lambda > 0 were post-RT independent prognostic factors for worse OS.

CONCLUSION

First-year post-RT PSA kinetics and minima are early response parameters predictive of overall survival for prostate cancer patients. These factors may be useful in selecting patients for early salvage therapy.