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.
Methodology
We identified the number of phase I, phase II, and phase III registered at clinicaltrials.gov by cancer (tumor) type. All counts were over the preceding 5 years (2008 to 2013). We compared these counts agains… Show more
“…Some studies were excluded because they did not measure links between trial registries and bibliographic databases and, instead, considered links to or from other source of clinical trial information. These included links to or from protocols [ 34 – 37 ], conference or meeting abstracts [ 38 – 42 ], internal company documents [ 17 ], Food and Drug Administration (FDA) documents or new drug approvals [ 43 – 47 ], or other databases of published articles [ 48 , 49 ]. Fig.…”
BackgroundStudies measuring the completeness and consistency of trial registration and reporting rely on linking registries with bibliographic databases. In this systematic review, we quantified the processes used to identify these links.MethodsPubMed and Embase databases were searched from inception to May 2016 for studies linking trial registries with bibliographic databases. The processes used to establish these links were categorised as automatic when the registration identifier was available in the bibliographic database or publication, or manual when linkage required inference or contacting of trial investigators. The number of links identified by each process was extracted where available. Linear regression was used to determine whether the proportions of links available via automatic processes had increased over time.ResultsIn 43 studies that examined cohorts of registry entries, 24 used automatic and manual processes to find articles; 3 only automatic; and 11 only manual (5 did not specify). Twelve studies reported results for both manual and automatic processes and showed that a median of 23% (range from 13 to 42%) included automatic links to articles, while 17% (range from 5 to 42%) of registry entries required manual processes to find articles. There was no evidence that the proportion of registry entries with automatic links had increased (R
2 = 0.02, p = 0.36). In 39 studies that examined cohorts of articles, 21 used automatic and manual processes; 9 only automatic; and 2 only manual (7 did not specify). Sixteen studies reported numbers for automatic and manual processes and indicated that a median of 49% (range from 8 to 97%) of articles had automatic links to registry entries, and 10% (range from 0 to 28%) required manual processes to find registry entries. There was no evidence that the proportion of articles with automatic links to registry entries had increased (R
2 = 0.01, p = 0.73).ConclusionsThe linkage of trial registries to their corresponding publications continues to require extensive manual processes. We did not find that the use of automatic linkage has increased over time. Further investigation is needed to inform approaches that will ensure publications are properly linked to trial registrations, thus enabling efficient monitoring of trial reporting.Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-017-0518-3) contains supplementary material, which is available to authorized users.
“…Some studies were excluded because they did not measure links between trial registries and bibliographic databases and, instead, considered links to or from other source of clinical trial information. These included links to or from protocols [ 34 – 37 ], conference or meeting abstracts [ 38 – 42 ], internal company documents [ 17 ], Food and Drug Administration (FDA) documents or new drug approvals [ 43 – 47 ], or other databases of published articles [ 48 , 49 ]. Fig.…”
BackgroundStudies measuring the completeness and consistency of trial registration and reporting rely on linking registries with bibliographic databases. In this systematic review, we quantified the processes used to identify these links.MethodsPubMed and Embase databases were searched from inception to May 2016 for studies linking trial registries with bibliographic databases. The processes used to establish these links were categorised as automatic when the registration identifier was available in the bibliographic database or publication, or manual when linkage required inference or contacting of trial investigators. The number of links identified by each process was extracted where available. Linear regression was used to determine whether the proportions of links available via automatic processes had increased over time.ResultsIn 43 studies that examined cohorts of registry entries, 24 used automatic and manual processes to find articles; 3 only automatic; and 11 only manual (5 did not specify). Twelve studies reported results for both manual and automatic processes and showed that a median of 23% (range from 13 to 42%) included automatic links to articles, while 17% (range from 5 to 42%) of registry entries required manual processes to find articles. There was no evidence that the proportion of registry entries with automatic links had increased (R
2 = 0.02, p = 0.36). In 39 studies that examined cohorts of articles, 21 used automatic and manual processes; 9 only automatic; and 2 only manual (7 did not specify). Sixteen studies reported numbers for automatic and manual processes and indicated that a median of 49% (range from 8 to 97%) of articles had automatic links to registry entries, and 10% (range from 0 to 28%) required manual processes to find registry entries. There was no evidence that the proportion of articles with automatic links to registry entries had increased (R
2 = 0.01, p = 0.73).ConclusionsThe linkage of trial registries to their corresponding publications continues to require extensive manual processes. We did not find that the use of automatic linkage has increased over time. Further investigation is needed to inform approaches that will ensure publications are properly linked to trial registrations, thus enabling efficient monitoring of trial reporting.Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-017-0518-3) contains supplementary material, which is available to authorized users.
“…This highlights the need to evaluate enrollment disparities further by both patient and trial characteristics within each under-represented population in order to better understand the extent and impact of disparities in trials and identify subgroups to target enrollment improvement efforts. Future analyses should evaluate whether there are differential enrollment rates among patients with different characteristics, tumor types and participation requirements that might impact patients' willingness to enroll (9). Given various trial characteristics and intensity, it is possible that limited social support and/ or financial constraints might differentially impact some patient groups more than others, potentially decreasing their likelihood of enrolling in cancer treatment trials.…”
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