Long-Term Effects and Over Diagnosis of Chest X-Ray and CT Scan in Lung Cancer

• Activity Number: 503
• Type: Contributed
• Date/Time: Wednesday, August 12, 2015 : 8:30 AM to 10:20 AM
• Sponsor: Biometrics Section
• Author(s): Dongfeng Wu*
• Companies: University of Louisville
• Keywords: over-diagnosis ; true-early-detection ; symptom-free-life ; sojourn time ; sensitivity ; transition probability

Abstract

Over diagnosis and long term outcomes of chest X-ray and Computed tomography (CT) scan in lung cancer screening were evaluated using the recently finished National Lung Screening Trial (NLST) data. Each participant would eventually fall into one of the four categories: true-early-detection, no-early-detection, over-diagnosis and symptom-free-life depending on whether they would be diagnosed with lung cancer and whether symptoms would have appeared before death. Bayesian inferences were made for percentages and credible intervals of the four outcomes using the derived probability formulae in Wu, Kafadar and Rosner (2014). We presented estimates for male and female heavy smokers using Markov Chain Monte Carlo (MCMC) samples in the simulation for both X-ray and CT scan group. Human lifetime was treated as a random variable derived from the actuarial life table from the US Social Security Administration (SSA). The probabilities of over diagnosis among the screen detected cases were also estimated. These probabilities show different patterns, since the sensitivity of CT (~0.96) is higher than traditional chest X-ray (~0.86).