title: Clinical trial spots for cancer patients by tumour type: The cancer trials portfolio at clinicaltrials.gov.
abstract: BACKGROUND
  Although participation in cancer clinical trials is low, little is known about the number of available clinical trials, and open spots for patients. Moreover, it is unclear what the relationship is between clinical trial openings and the incidence and mortality of cancer subtypes.
  
  
  METHODS
  We identified the number of phase I, phase II and phase III registered at clinicaltrials.gov by cancer (tumour) type. All counts were over the preceding 5 years (2008-2013). We compared these counts against the incidence and prevalence of disease reported by Surveillance, Epidemiology and End Results (SEER) database for 32 common cancers.
  
  
  RESULTS
  From 2008 to 2013, 3879 phase I trials, 4982 phase II trials and 1379 phase III trials concerning a cancer subtype were registered in clinicaltrials.gov. These trials had a cumulative proposed recruitment of 203,396, 421,502 and 697,787 patients, respectively. Trial enrollment varied by tumour type, with both over and under-representation occurring.
  
  
  CONCLUSIONS
  Opportunities to enroll in clinical trials vary by phase and tumour type. Oncologists must remain committed to clinical trials.
authors: Medical Oncology Branch, National Cancer Institute, National Institutes of Health, 10 Center Dr. 10/12N226, Bethesda, MD 20892, United States. Electronic address: vinayakkprasad@gmail.com.
authors: Vinay
authors: V
authors: Prasad
authors: Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, United States. Electronic address: jeffery.a.goldstein@vanderbilt.edu.
authors: Jeffery A
authors: JA
authors: Goldstein
mesh_terms: D017321:Clinical Trials, Phase I as Topic / Q000706:statistics & numerical data*; D017322:Clinical Trials, Phase II as Topic / Q000706:statistics & numerical data*; D017326:Clinical Trials, Phase III as Topic / Q000706:statistics & numerical data*; D016208:Databases, Factual / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D009317:National Library of Medicine (U.S.); D009369:Neoplasms / Q000145:classification / Q000453:epidemiology / Q000628:therapy*; D018579:Patient Selection; D012042:Registries / Q000706:statistics & numerical data; D035842:Research Subjects / Q000706:statistics & numerical data; D018426:SEER Program / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology
keywords: Burden of disease; Cancer clinical trials; Cancer trials; Cancer trials portfolio; Clinicaltrials.gov; Phase I, phase II and phase III