An estimator for treatment comparisons among survivors in randomized trials.

In clinical trials of advanced-stage disease it is often of interest to perform treatment comparisons for endpoints which are defined only for survivors. Examples include time on ventilation in ventilation studies, change in quality of life in health-related quality-of-life studies, and duration of response to therapy in therapeutic trials. Randomized treatment comparisons for these endpoints cannot be performed because the outcomes are only defined in the nonrandomly selected subgroup of survivors.

An educational program to increase cervical and breast cancer screening in Hispanic women: a Southwest Oncology Group study.

We conducted a community-based pilot study to train Hispanic cancer survivors as promotoras (lay health educators) to encourage their social contacts to obtain breast and cervical cancer screening. Promotoras were recruited from a private oncologist's practice at a Minority-Based Community Clinical Oncology Program (MBCCOP). Five Hispanic women were trained to serve as promotoras by attending a 12-week course.

Prevalence of prostate cancer among men with a prostate-specific antigen level < or =4.0 ng per milliliter.

Background: The optimal upper limit of the normal range for prostate-specific antigen (PSA) is unknown. We investigated the prevalence of prostate cancer among men in the Prostate Cancer Prevention Trial who had a PSA level of 4.0 ng per milliliter or less.

Rates of study completion with single versus split daily dosing of antidepressants: a meta-analysis.

Objective: To examine the tolerability of single versus multiple daily dosing (SDD vs. MDD) of antidepressant drugs in clinical practice.

Method: Studies comparing single versus multiple daily dosing of antidepressants were reviewed.

Statistics in clinical trials.

Statistical developments over the past several years are described in this review. Efforts in phase I studies have focused on efficient estimation of maximum tolerated dose. Issues investigated for phase II trials include incorporation of multiple endpoints and randomization.

Health status and quality of life in patients with early-stage Hodgkin's disease treated on Southwest Oncology Group Study 9133.

Purpose: We describe the short and intermediate-term quality-of-life (QOL) outcomes in patients treated on a randomized clinical trial in early-stage Hodgkin's disease (Southwest Oncology Group [SWOG] 9133) comparing subtotal lymphoid irradiation (STLI) with combined-modality treatment (CMT).

Patients And Methods: Two hundred forty-seven patients participated in the QOL study (SWOG 9208), completing several standardized instruments (Symptom Distress Scale; Cancer Rehabilitation Evaluation System - Short Form; Medical Outcomes Study 36-Item Short-Form Health Survey Vitality Scale; and a health perception item), as well as questions about work, marital status, and concerns about having children. This article reports on results from baseline before random assignment, at 6 months, and at 1 and 2 years after random assignment.

Pattern mixture models for longitudinal quality of life studies in advanced stage disease.

Analyses of longitudinal quality of life (QOL) for patients with advanced stage disease are frequently plagued by problems of non-random drop-out attributable to deteriorating health and/or death. As an example, Moinpour et al. cite specific challenges which limited their report and assessment of QOL for patients treated for advanced stage colorectal cancer in a clinical trial of several chemotherapeutic regimes performed by the Southwest Oncology Group.

Biomarker-based methods for determining noncompliance in a prevention trial.

The Prostate Cancer Prevention Trial (PCPT) is a 7-year randomized trial of 18000 men designed to test a daily dose of finasteride (5 mg/d) for the primary prevention of prostate cancer. Compliance is assessed every 6 months by determining the percentage of pills consumed since the previous visit. In addition, levels of 5 alpha-dihydrotestosterone (DHT) are measured at yearly intervals in a random subset of 5% of participants in the trial as part of a substudy to investigate the potential of this biomarker for monitoring compliance.

Predicting time to prostate cancer recurrence based on joint models for non-linear longitudinal biomarkers and event time outcomes.

Biological markers that are both sensitive and specific for tumour regrowth or metastasis are increasingly becoming available and routinely monitored during the regular follow-up of patients treated for cancer. Obtained by a simple blood test, these markers provide an inexpensive non-invasive means for the early detection of recurrence (or progression). Currently, the longitudinal behaviour of the marker is viewed as an indicator of early disease progression, and is applied by a physician in making clinical decisions.

Non-linear hierarchical models for monitoring compliance.

As biomarkers transformable by specific drug agents increasingly become available, so their usefulness also increases for monitoring compliance in clinical and prevention trials, and for subsequent monitoring in the general population if a treatment is found successful. Marker levels measured over the course of a treatment yield a longitudinal trajectory that is typically non-linear, with varying velocities during the phase-in and steady-state periods of treatment, followed by decays back to normal in the presence of non-compliance. There is often considerable between-individual variability both in the mean parameters of the trajectory and the variability over time.