Abstract:
:In this paper, we proposed a mechanistic breast cancer survival model based on the axillary lymph node chain structure, considering lymph nodes as a potential dissemination arrangement. We assume a naive breast cancer treatment protocol consisting of exposing patients first to a chemotherapy treatment on r intervals at k-cycles separated by equal time intervals, and then they proceed to surgery. Our model, different from former ones, accommodates a quantity of contaminated lymph nodes, which is observed during surgery. We assume a generalised negative binomial survival distribution for the unknown number of contaminated lymph nodes after surgery, which, during an unknown period, may potentially propagate the disease. Estimation is based on a maximum likelihood approach. A simulation study assesses the coverage probability of asymptotic confidence intervals when small or moderate samples are considered. A Brazilian breast cancer data illustrate the applicability of our modelling.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Cobre J,Castro Perdoná GS,Peria FM,Louzada Fdoi
10.1002/sim.5576subject
Has Abstractpub_date
2013-04-30 00:00:00pages
1536-46issue
9eissn
0277-6715issn
1097-0258journal_volume
32pub_type
杂志文章abstract::To study the spread of sexually transmitted diseases (STDs) using social/sexual mixing models, one must have quantitative information about sexual mixing. An unavoidable complication in gathering such information by survey is that members of the surveyed population will almost certainly have sexual contacts outside th...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780111202
更新日期:1992-09-15 00:00:00
abstract::A technique is presented which provides guidance on the spacing of follow-up waves in a multiwave study. Only information from the baseline wave is needed, as well as rough parameter estimates for the survival distribution. The computations use the expected Fisher information; a new method for its calculation is given...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780101209
更新日期:1991-12-01 00:00:00
abstract::Quality of life (QOL) assessment is a key component of many clinical studies and frequently requires the use of single global summary measures that capture the overall balance of findings from a potentially wide-ranging assessment of QOL issues. We propose and evaluate an irregular multilevel latent variable model sui...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4455
更新日期:2012-05-20 00:00:00
abstract::In biomedical literature, numerous prediction models for clinical outcomes have been developed based either on clinical data or, more recently, on high-throughput molecular data (omics data). Prediction models based on both types of data, however, are less common, although some recent studies suggest that a suitable c...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6246
更新日期:2014-12-30 00:00:00
abstract::In observational studies, many continuous or categorical covariates may be related to an outcome. Various spline-based procedures or the multivariable fractional polynomial (MFP) procedure can be used to identify important variables and functional forms for continuous covariates. This is the main aim of an explanatory...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5639
更新日期:2013-06-15 00:00:00
abstract::Proportional odds regression models for multinomial probabilities based on ordered categories have been generalized in two somewhat different directions. Models having scale as well as location parameters for adjustment of boundaries (on an unobservable, underlying continuum) between categories have been employed in t...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780141105
更新日期:1995-06-15 00:00:00
abstract::The power prior has been widely used in many applications covering a large number of disciplines. The power prior is intended to be an informative prior constructed from historical data. It has been used in clinical trials, genetics, health care, psychology, environmental health, engineering, economics, and business. ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6728
更新日期:2015-12-10 00:00:00
abstract::In studies with survival or time-to-event outcomes, a competing risk is an event whose occurrence precludes the occurrence of the primary event of interest. Specialized statistical methods must be used to analyze survival data in the presence of competing risks. We conducted a review of randomized controlled trials wi...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.7215
更新日期:2017-04-15 00:00:00
abstract::Tree-based methods have become popular for analyzing complex data structures where the primary goal is risk stratification of patients. Ensemble techniques improve the accuracy in prediction and address the instability in a single tree by growing an ensemble of trees and aggregating. However, in the process, individua...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4492
更新日期:2012-07-10 00:00:00
abstract::A common problem encountered in many medical applications is the comparison of survival curves. Often, rather than comparison of the entire survival curves, interest is focused on the comparison at a fixed point in time. In most cases, the naive test based on a difference in the estimates of survival is used for this ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2864
更新日期:2007-10-30 00:00:00
abstract::With reference to a real data on cataract surgery, we discuss the problem of zero-inflated circular-circular regression when both covariate and response are circular random variables and a large proportion of the responses are zeros. The regression model is proposed, and the estimation procedure for the parameters is ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7496
更新日期:2018-01-15 00:00:00
abstract::The purpose of this paper is to show that the sensitivity and specificity estimates obtained by 'discrepant analysis' are biased. Discrepant analysis is a widely used technique that attempts to provide estimates of sensitivity and specificity in the presence of an imperfect gold standard. Many researchers have applied...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970630)16:12<1391::aid-s
更新日期:1997-06-30 00:00:00
abstract::In this work, we describe a two-stage sampling design to estimate the infection prevalence in a population. In the first stage, an imperfect diagnostic test was performed on a random sample of the population. In the second stage, a different imperfect test was performed in a stratified random sample of the first sampl...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6545
更新日期:2015-11-10 00:00:00
abstract::In the field of cluster detection, a weighted normal model-based scan statistic was recently developed to analyze regional continuous data and to evaluate the clustering pattern of pre-defined cells (such as state, county, tract, school, hospital) that include many individuals. The continuous measures of interest are,...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3990
更新日期:2010-10-15 00:00:00
abstract::We consider the use of the assurance method in clinical trial planning. In the assurance method, which is an alternative to a power calculation, we calculate the probability of a clinical trial resulting in a successful outcome, via eliciting a prior probability distribution about the relevant treatment effect. This i...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5916
更新日期:2014-01-15 00:00:00
abstract::Service on the Data Monitoring Committee of the CPEP (Calcium for Pre-eclampsia Prevention) has led us to four conclusions about clinical trials which we should like to present to this gathering of biostatisticians for their reactions: (i) meta-analyses of the pertinent published trials of the same therapy should alwa...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0258(19960630)15:12<1263::AID-S
更新日期:1996-06-30 00:00:00
abstract::Relative potency is a measure that has been used for many years to summarize the comparison of dose-response curves in parallel line bioassays. When response curves for two preparations are not parallel the traditional definition of relative potency no longer applies. We review the concept of relative potency and show...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970530)16:10<1151::aid-s
更新日期:1997-05-30 00:00:00
abstract:BACKGROUND:The need to deliver interventions targeting multiple diseases in a cost-effective manner calls for integrated disease control efforts. Consequently, maps are required that show where the risk of co-infection is particularly high. Co-infection risk is preferably estimated via Bayesian geostatistical multinomi...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4243
更新日期:2011-06-30 00:00:00
abstract::When asking 'what is known' about a drug or therapy or program at any time, both researchers and practitioners often confront more than a single study. Facing a variety of findings, where conflicts may outweigh agreement, how can a reviewer constructively approach the task? In this discussion, I will outline some ques...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780060304
更新日期:1987-04-01 00:00:00
abstract::This paper investigates the Bayesian procedures for comparing proportions. These procedures are especially suitable for accepting (or rejecting) the equivalence of two population proportions. Furthermore the Bayesian predictive probabilities provide a natural and flexible tool in monitoring trials, especially for choo...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780140924
更新日期:1995-05-15 00:00:00
abstract::We propose to use a very simple model to test whether a cancer cluster is due to chance alone. We focus on the acute childhood leukaemia cluster in Columbus, Ohio. In 1975, 12 leukaemia cases were observed in Columbus while the expected number is 6 cases per year. According to our simple model, the probability of such...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/1097-0258(20000830)19:16<2195::aid-sim522>
更新日期:2000-08-30 00:00:00
abstract::We applied a computationally practical form of probit analysis for multiple response variables to data on early childhood development of four psychiatric disorders: disruptive disorders (DD-attention deficit disorders, oppositional defiant disorder, conduct disorder); adjustment disorders (ADJ); emotional disorders (E...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19981115)17:21<2487::aid-s
更新日期:1998-11-15 00:00:00
abstract::We develop analysis methods for clinical trials with time-to-event outcomes which correct for treatment changes during follow-up, yet are based on comparisons of randomized groups and not of selected groups. A causal model relating observed event times to event times that would have been observed under other treatment...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19991015)18:19<2617::aid-s
更新日期:1999-10-15 00:00:00
abstract::Hot-deck imputation is an intuitively simple and popular method of accommodating incomplete data. Users of the method will often use the usual multiple imputation variance estimator which is not appropriate in this case. However, no variance expression has yet been derived for this easily implemented method applied to...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970115)16:1<5::aid-sim46
更新日期:1997-01-15 00:00:00
abstract::Reference ranges which take time (such as age) into account are often required in medicine, but simple, systematic and efficient statistical methods for constructing them are lacking. A method is described which is based on low order polynomial curves (linear, quadratic or occasionally cubic), together with guidelines...
journal_title:Statistics in medicine
pub_type: 临床试验,杂志文章,多中心研究
doi:10.1002/sim.4780100502
更新日期:1991-05-01 00:00:00
abstract::In vaccine safety studies, subjects are considered at increased risk for adverse events for a period of time after vaccination known as risk window. To our knowledge, risk windows for vaccine safety studies have tended to be pre-defined and not to use information from the current study. Inaccurate specification of the...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4125
更新日期:2011-03-30 00:00:00
abstract::Many Americans rely on cardiac surgical procedures and devices such as pacemakers and thrombolytic catheters to treat or manage their cardiovascular diseases. However, the failure of these cardiac devices and procedures could have grave consequences. One reason cardiac devices tended to fail was due to physician error...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7906
更新日期:2018-12-10 00:00:00
abstract::This article deals with determination of a sample size that guarantees the success of a trial. We follow a Bayesian approach and we say an experiment is successful if it yields a large posterior probability that an unknown parameter of interest (an unknown treatment effect or an effects-difference) is greater than a c...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3175
更新日期:2008-06-15 00:00:00
abstract::Kappa coefficients are measures of correlation between categorical variables often used as reliability or validity coefficients. We recapitulate development and definitions of the K (categories) by M (ratings) kappas (K x M), discuss what they are well- or ill-designed to do, and summarize where kappas now stand with ...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.1180
更新日期:2002-07-30 00:00:00
abstract::In this study, 401 cases of childhood cancer in four California counties in 1980-1988 were analysed with the innovative methodology of density equalizing map projections. The data were originally collected and analysed by the California State Department of Health Services (DHS). In addition to the new analytic techniq...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.686
更新日期:2001-05-15 00:00:00