title: Assessing the Eventual Publication of Clinical Trial Abstracts Submitted to a Large Annual Oncology Meeting.
abstract: BACKGROUND
  Despite the ethical imperative to publish clinical trials when human subjects are involved, such data frequently remain unpublished. The objectives were to tabulate the rate and ascertain factors associated with eventual publication of clinical trial results reported as abstracts in the Proceedings of the American Society of Clinical Oncology (American Society of Clinical Oncology).
  
  
  METHODS
  Abstracts describing clinical trials for patients with breast, lung, colorectal, ovarian, and prostate cancer from 2009 to 2011 were identified by using a comprehensive online database (http://meetinglibrary.asco.org/abstracts). Abstracts included reported results of a treatment or intervention assessed in a discrete, prospective clinical trial. Publication status at 4-6 years was determined by using a standardized search of PubMed. Primary outcomes were the rate of publication for abstracts of randomized and nonrandomized clinical trials. Secondary outcomes included factors influencing the publication of results.
  
  
  RESULTS
  A total of 1,075 abstracts describing 378 randomized and 697 nonrandomized clinical trials were evaluated. Across all years, 75% of randomized and 54% of nonrandomized trials were published, with an overall publication rate of 61%. Sample size was a statistically significant predictor of publication for both randomized and nonrandomized trials (odds ratio [OR] per increase of 100 participants = 1.23 [1.11-1.36], p < .001; and 1.64 [1.15-2.34], p = .006, respectively). Among randomized studies, an industry coauthor or involvement of a cooperative group increased the likelihood of publication (OR 2.37, p = .013; and 2.21, p = .01, respectively). Among nonrandomized studies, phase II trials were more likely to be published than phase I (p < .001). Use of an experimental agent was not a predictor of publication in randomized (OR 0.76 [0.38-1.52]; p = .441) or nonrandomized trials (OR 0.89 [0.61-1.29]; p = .532).
  
  
  CONCLUSIONS
  This is the largest reported study examining why oncology trials are not published. The data show that 4-6 years after appearing as abstracts, 39% of oncology clinical trials remain unpublished. Larger sample size and advanced trial phase were associated with eventual publication; among randomized trials, an industry-affiliated author or a cooperative group increased likelihood of publication. Unfortunately, we found that, despite widespread recognition of the problem and the creation of central data repositories, timely publishing of oncology clinical trials results remains unsatisfactory.
authors.affiliation: Dell Medical School, University of Texas at Austin, Austin, Texas, USA prmassey@seton.org.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Massey
authors.affiliation: Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Ruibin
authors.initials: R
authors.lastname: Wang
authors.affiliation: Medical Oncology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Vinay
authors.initials: V
authors.lastname: Prasad
authors.affiliation: Medical Oncology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Bates
authors.affiliation: Medical Oncology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Tito
authors.initials: T
authors.lastname: Fojo
mesh_terms: D000970:Antineoplastic Agents; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D006801:Humans; D008495:Medical Oncology; D009369:Neoplasms / Q000188:drug therapy; D011642:Publications / Q000706:statistics & numerical data*; D011643:Publishing / Q000706:statistics & numerical data*; D012955:Societies, Medical
chemical_list: D000970:Antineoplastic Agents
keywords: ClinicalTrials.gov; Oncology clinical trials; Publication rates