Search

BackgroundClinical trials are essential to establish the effectiveness of new cancer therapies, but less than 5% of adults with cancer enroll in trials. In addition to ineligibility or lack of available trials, barriers to enrollment may include limited patient awareness about the option of participation.MethodsWe surveyed a multiregional cohort of patients with lung or colorectal cancer (or their surrogates) three to six months after diagnosis. We assessed whether respondents reported learning that clinical trial participation might be an option, and, if so, with whom they discussed trials. We used logistic regression to assess the association of patient characteristics with discussing trial participation and enrolling in trials. All statistical tests were two-sided.ResultsOf 7887 respondents, 1114 (14.1%) reported discussing the possibility of clinical trial participation; most learned about trials from their physicians, and 287 patients (3.6% of all patients, 25.8% of trial discussants) enrolled. Among 2173 patients who received chemotherapy for advanced (stage III/IV lung or stage IV colorectal) cancer, 25.7% discussed trials, and 7.6% (29.5% of trial discussants) enrolled. Discussions were less frequent among older patients, African American or Asian vs white patients, and those with lower incomes and more comorbidity. Enrollment was higher among patients reporting shared vs physician-driven decisions (all P < .05).ConclusionsIn this population-based cohort, only 14% of patients discussed participation in clinical trials. Discussions were more frequent among advanced cancer patients but were still reported by a minority of patients. Strategies to expand access to trials and facilitate patient-provider communication about participation may accelerate development of better cancer therapeutics.

A study was conducted to investigate and evaluate the benefits of adjuvant chemotherapy use and outcomes among older patients with stage III colon cancer. Results indicated that such patients received less toxic and had shorter chemotherapy regimens and had lesser adverse events.

This is the second part of a two-part paper in which application methods to enhance distribution horizon planning for a 20+ year period are described. The optimal horizon planning model encompasses all distribution design requirements for primary and secondary systems. The model formulation is described in the companion paper Part I. The model makes use of a generalized feeder layout viewed as a tree-like circuit serving a circular sector of a round or hexagonal service area of uniform load density. The horizon model optimization objective cost function and constraint equation applications are described in this paper. The horizon planning model is validated with analysis of case studies and sensitivity evaluations for input and output variables. The case studies are assessed under various conditions such as changing consumer density, consumer characteristics, cost of energy, and economic assumptions. The application of the model is demonstrated using Snohomish PUD future expansion assumptions with case studies to examine impacts of horizon assumptions on future conductor sizes, primary voltage classes, voltage drop designs, reliability, and consumer cost of service. Index Terms--Circuit optimization, losses, minimization methods, optimization methods, power distribution economics, power distribution lines, power distribution planning.

This paper is the first of a two-part paper on optimal distribution system planning. The horizon distribution planning problem and optimal distribution system model formulation are described. The horizon planning mission is to minimize future costs by determining optimal design parameters given assumptions about the future. Prior work addressed short-range and expansion planning of subsets or combinations of design parameters. The many distribution requirements and associated constraints inhibited an all-inclusive evaluation of total horizon design requirements for the 20+ year period. The proposed model and optimization formulation provides a generalized horizon planning approach and introduce a fully functioning comprehensive horizon planning model using a perspective that encompasses all necessary parameters and constraints. Parameters include: substation and distribution transformer capacities; number, size, and lengths of distribution feeders and secondary conductors; and primary voltage class. Optimal design voltage drops and reliability indices are determined. The horizon planning optimization application is described and solved in the second companion paper using continuous constrained nonlinear programming methods. The application is demonstrated with Snohomish PUD case studies. Index Terms--Circuit optimization, losses, minimization methods, optimization methods, power distribution economics, power distribution lines, power distribution planning.

Faults on the electric power distribution system are responsible for a large portion of the interruptions that a customer will experience. To maintain a high level of system reliability, vegetation maintenance is often required. Analytical prediction of the effects of vegetation maintenance on distribution system reliability requires a model of the expected failure rate of line sections that includes the effects of vegetation. Vegetation-related failures are more likely to occur as the vegetation near the overhead power lines grows, increasing the line-section failure rate. Due to difficulties in using existing growth models, this paper proposes to use a direct model for failure-rate prediction based on factors that affect vegetation growth. Four models are considered: linear regression, exponential regression, linear multivariable regression, and an artificial neural network (ANN). The models are tested with historical vegetation growth parameter data and feeder failure rates. Results are compared and the features of each model are discussed. Index Terms--Failure-rate modeling, failure-rate prediction, line clearance, neural networks, power distribution systems, regression, reliability, tree trimming, vegetation maintenance.

Certain vitamins can prevent some chronic diseases if taken in adequate amounts. Folate can prevent neural tube defects and some types of cancer. Folate, vitamin B6 and vitamin B12 can prevent cardiovascular disease. Vitamin E can lower the risk of prostate cancer, and vitamin D can lower the risk of bone fractures., Context: Although vitamin deficiency is encountered infrequently in developed countries, inadequate intake of several vitamins is associated with chronic disease. Objective: To review the clinically important vitamins with regard to their biological effects, food sources, deficiency syndromes, potential for toxicity, and relationship to chronic disease. Data Sources and Study Selection: We searched MEDLINE for Englishlanguage articles about vitamins in relation to chronic diseases and their references published from 1966 through January 11, 2002. Data Extraction: We reviewed articles jointly for the most clinically important information, emphasizing randomized trials where available. Data Synthesis: Our review of 9 vitamins showed that elderly people, vegans, alcohol-dependent individuals, and patients with malabsorption are at higher risk of inadequate intake or absorption of several vitamins. Excessive doses of vitamin A during early pregnancy and fat-soluble vitamins taken anytime may result in adverse outcomes. Inadequate folate status is associated with neural tube defect and some cancers. Folate and vitamins B6 and B12 are required for homocysteine metabolism and are associated with coronary heart disease risk. Vitamin E and lycopene may decrease the risk of prostate cancer. Vitamin D is associated with decreased occurrence of fractures when taken with calcium. Conclusions: Some groups of patients are at higher risk for vitamin deficiency and suboptimal vitamin status. Many physicians may be unaware of common food sources of vitamins or unsure which vitamins they should recommend for their patients. Vitamin excess is possible with supplementation, particularly for fat-soluble vitamins. Inadequate intake of several vitamins has been linked to chronic diseases, including coronary heart disease, cancer, and osteoporosis.