Clinical trials data
Cognitive tests in cancer trials: 760 registered studies
Every registered cancer study on ClinicalTrials.gov that names a cognitive test in an outcome measure: the tests used most, how often as a primary outcome, which tests go together, how large the studies are and when they measure the outcome.
- Registered cancer studies name a cognitive test in an outcome
- 760
- Led by industry
- 48
The tests cancer trials use most
Verbal Learning leads: 235 of the 760 studies name it, 31%. Next comes Verbal Fluency (200). As a primary outcome, Verbal Learning leads with 77 studies.
- 1
Verbal Learning235 studies, 77 as a primary outcome
- 2
Verbal Fluency200 studies, 64 as a primary outcome
- 3
Trail Making Test187 studies, 54 as a primary outcome
- 4
Digit Span Test107 studies, 41 as a primary outcome
- 5
Stroop Color-Word Test65 studies, 33 as a primary outcome
- 6
Symbol Coding58 studies, 27 as a primary outcome
- 7
Continuous Performance Test35 studies, 14 as a primary outcome
- 8
Category Fluency26 studies, 10 as a primary outcome
- 9
N-Back Task19 studies, 9 as a primary outcome
- 10
Task Switching Test16 studies, 6 as a primary outcome
- 11
Paced Visual Serial Addition Test15 studies, 8 as a primary outcome
- 12
Picture Naming Test14 studies, 8 as a primary outcome
- 13
Short Story Recall14 studies, 5 as a primary outcome
- 14
Symbol Scan Task13 studies, 4 as a primary outcome
- 15
Size Order Memory Test11 studies, 4 as a primary outcome
- 16
Clock Drawing Task11 studies, 3 as a primary outcome
- 17
Go/No-Go Task10 studies, 6 as a primary outcome
- 18
Card Sorting Test (Berg)10 studies, 4 as a primary outcome
- 19
Delayed Match-to-Sample9 studies, 3 as a primary outcome
- 20
Vocabulary Test9 studies, 2 as a primary outcome
- 21
Complex Figure Copy and Recall8 studies, 5 as a primary outcome
- 22
Delay Discounting8 studies, 4 as a primary outcome
- 23
Corsi Block-Tapping Test7 studies, 4 as a primary outcome
- 24
Eriksen Flanker Task7 studies, 4 as a primary outcome
- 25
Rapid Visual Information Processing7 studies, 3 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
32% of cancer studies name only instruments outside the library, such as clinician-administered screening scales. They count in every figure on this page and are not listed. The explorer below holds all 88 tests.
Tests used together
- Verbal Fluency and Verbal Learning136 studies name both
- Trail Making Test and Verbal Learning121 studies name both
- Trail Making Test and Verbal Fluency119 studies name both
- Digit Span Test and Verbal Learning66 studies name both
- Digit Span Test and Verbal Fluency62 studies name both
- Digit Span Test and Trail Making Test52 studies name both
- Symbol Coding and Verbal Learning32 studies name both
- Digit Span Test and Symbol Coding27 studies name both
- Symbol Coding and Trail Making Test27 studies name both
- Stroop Color-Word Test and Trail Making Test26 studies name both
Studies by start year
A test as a primary outcomeOnly in secondary or other outcomes
Show as a table
| Start year | Studies | A test as a primary outcome |
|---|---|---|
| 2000 | 1 | 0 |
| 2001 | 1 | 1 |
| 2002 | 4 | 1 |
| 2003 | 2 | 2 |
| 2004 | 2 | 1 |
| 2005 | 6 | 3 |
| 2006 | 4 | 1 |
| 2007 | 10 | 2 |
| 2008 | 13 | 5 |
| 2009 | 13 | 6 |
| 2010 | 11 | 5 |
| 2011 | 14 | 6 |
| 2012 | 16 | 7 |
| 2013 | 24 | 9 |
| 2014 | 27 | 10 |
| 2015 | 36 | 17 |
| 2016 | 34 | 14 |
| 2017 | 45 | 12 |
| 2018 | 32 | 13 |
| 2019 | 52 | 17 |
| 2020 | 40 | 10 |
| 2021 | 67 | 21 |
| 2022 | 56 | 20 |
| 2023 | 52 | 14 |
| 2024 | 62 | 23 |
| 2025 | 62 | 17 |
| 2026 | 66 | 34 |
Phases and sponsors
By phase
- Early phase 14 studies, 1 as a primary outcome
- Phase 120 studies, 2 as a primary outcome
- Phase 1/226 studies, 7 as a primary outcome
- Phase 2111 studies, 22 as a primary outcome
- Phase 2/37 studies, 1 as a primary outcome
- Phase 370 studies, 20 as a primary outcome
- Phase 413 studies, 3 as a primary outcome
- Not applicable356 studies, 142 as a primary outcome
- Observational153 studies, 76 as a primary outcome
Sponsors and study types
Lead sponsor: industry 48, NIH 9, universities, hospitals and others 703. Interventional 607, observational 153.
Status, results, interventions and countries
Status
- Recruiting166 studies, 56 as a primary outcome
- Not yet recruiting48 studies, 24 as a primary outcome
- Active, not recruiting71 studies, 22 as a primary outcome
- Completed300 studies, 115 as a primary outcome
- Stopped early76 studies, 19 as a primary outcome
- Status unknown99 studies, 38 as a primary outcome
What they test
- Behavioral185 studies, 84 as a primary outcome
- Drug221 studies, 53 as a primary outcome
- Device76 studies, 23 as a primary outcome
- Dietary supplement10 studies, 4 as a primary outcome
- Procedure67 studies, 23 as a primary outcome
- Diagnostic test19 studies, 6 as a primary outcome
- Biological16 studies, 2 as a primary outcome
- Radiation140 studies, 40 as a primary outcome
- Combination product7 studies, 1 as a primary outcome
- Genetic1 studies, 0 as a primary outcome
- Other215 studies, 78 as a primary outcome
- None given60 studies, 32 as a primary outcome
Intervention types as registered. A study can list several; observational studies often list none.
Where their sites are
- United States330 studies, 128 as a primary outcome
- France77 studies, 12 as a primary outcome
- Canada72 studies, 19 as a primary outcome
- China58 studies, 18 as a primary outcome
- Germany42 studies, 5 as a primary outcome
- Spain40 studies, 10 as a primary outcome
- Italy35 studies, 8 as a primary outcome
- Netherlands34 studies, 5 as a primary outcome
- United Kingdom27 studies, 6 as a primary outcome
- Australia26 studies, 3 as a primary outcome
- Belgium25 studies, 4 as a primary outcome
- Denmark24 studies, 8 as a primary outcome
60 countries in all. A study with sites in several counts in each; 37 list no site.
Reported results
Completed studies with results posted on ClinicalTrials.gov, a results paper the registry links to the study, or both.
Completed cancer studies: 135 of 300, 45%
Every completed study with a cognitive outcome: 3,626 of 7,953, 46%
| Results | Completed cancer studies | Every completed study |
|---|---|---|
| Results on ClinicalTrials.gov and a paper | 31, 10% | 776, 10% |
| Results on ClinicalTrials.gov only | 48, 16% | 1,139, 14% |
| A results paper only | 56, 19% | 1,711, 22% |
| Neither | 165, 55% | 4,327, 54% |
How many participants they enroll
- Phase 121 median, 15 to 47
- Phase 1/246 median, 21 to 87
- Phase 260 median, 30 to 112
- Phase 3226 median, 91 to 411
- Phase 457 median, 49 to 285
- Not applicable60 median, 31 to 118
- Observational100 median, 50 to 200
Show as a table
| Phase | Studies with a size | Median | Middle half |
|---|---|---|---|
| Phase 1 | 19 | 21 | 15 to 47 |
| Phase 1/2 | 24 | 46 | 21 to 87 |
| Phase 2 | 110 | 60 | 30 to 112 |
| Phase 3 | 69 | 226 | 91 to 411 |
| Phase 4 | 11 | 57 | 49 to 285 |
| Not applicable | 346 | 60 | 31 to 118 |
| Observational | 151 | 100 | 50 to 200 |
When the cognitive outcome is measured
Latest time point of each outcome
- Within a day92 outcomes, 40 as a primary outcome
- Up to 4 weeks105 outcomes, 35 as a primary outcome
- 1 to 3 months229 outcomes, 109 as a primary outcome
- 3 to 6 months286 outcomes, 107 as a primary outcome
- 6 to 12 months280 outcomes, 91 as a primary outcome
- 1 to 2 years117 outcomes, 38 as a primary outcome
- Over 2 years118 outcomes, 30 as a primary outcome
- No duration given39 outcomes, 23 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
1,227 of the 1,266 outcome measures give a duration. A single visit counts as within a day.
Median time to the primary outcome, by test
| Test | Primary outcomes | Median |
|---|---|---|
| Verbal Learning | 76 | 6 months |
| Verbal Fluency | 62 | 4 months |
| Trail Making Test | 51 | 6 months |
| Digit Span Test | 38 | 6 months |
| Stroop Color-Word Test | 32 | 4 months |
| Symbol Coding | 25 | 6 months |
| Continuous Performance Test | 13 | 6 months |
| Category Fluency | 10 | 6 months |
Explore the cancer studies
519 studies match. 220 name a library test in a primary outcome. Median size 70 participants. Median time to the primary outcome: 4 months.
Loading 519 studies; the filters turn on when they arrive.
2026 is partly planned starts. Not shown: 2 that started before 2000 and 5 planned to start after 2026.
Show as a table
| Start year | Studies | As a primary outcome |
|---|---|---|
| 2000 | 1 | 0 |
| 2001 | 1 | 1 |
| 2002 | 3 | 0 |
| 2003 | 2 | 2 |
| 2004 | 2 | 1 |
| 2005 | 3 | 2 |
| 2006 | 3 | 1 |
| 2007 | 6 | 1 |
| 2008 | 5 | 3 |
| 2009 | 10 | 5 |
| 2010 | 7 | 4 |
| 2011 | 12 | 6 |
| 2012 | 13 | 7 |
| 2013 | 16 | 9 |
| 2014 | 21 | 9 |
| 2015 | 25 | 13 |
| 2016 | 24 | 8 |
| 2017 | 33 | 11 |
| 2018 | 25 | 13 |
| 2019 | 28 | 15 |
| 2020 | 25 | 9 |
| 2021 | 50 | 18 |
| 2022 | 37 | 17 |
| 2023 | 36 | 11 |
| 2024 | 38 | 14 |
| 2025 | 41 | 12 |
| 2026 | 45 | 25 |
Library tests named most
Largest condition groups
Phases
Participants
Lead sponsor: industry 28, NIH 7, other 484. Interventional 423, observational 96.
As a primary outcomeSecondary or other outcome
The studies, newest registration first
Each number opens the study's record on ClinicalTrials.gov.
| Study | Start | Phase | Conditions | Participants | Lead sponsor | Status | Library tests named, with the latest time point |
|---|---|---|---|---|---|---|---|
| NCT07908147 | Start2027 | PhaseEarly phase 1 | ConditionsCancer | Participants12 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07899827 | Start2027 | PhaseNot applicable | ConditionsCancer, Substance use and addiction | Participants50 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07867886 | Start2026 | PhaseNot applicable | ConditionsCancer | Participants30 | Lead sponsorIndustry | StatusNot yet recruiting | Library tests named
|
| NCT07836478 | Start2026 | PhaseObservational | ConditionsCancer | Participants60 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07769099 | Start2026 | PhaseNot applicable | ConditionsCancer | Participants236 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07755839 | Start2026 | PhaseNot applicable | ConditionsDepression and bipolar disorder, Cancer, Anxiety, PTSD and OCD | Participants60 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07743086 | Start2026 | PhasePhase 1/2 | ConditionsCancer | Participants886 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07740616 | Start2027 | PhaseNot applicable | ConditionsCancer | Participants30 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07740317 | Start2026 | PhaseObservational | ConditionsCancer | Participants50 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07729969 | Start2026 | PhaseNot applicable | ConditionsCancer | Participants110 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07716800 | Start2026 | PhaseObservational | ConditionsCancer, Delirium, surgery and intensive care | Participants205 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07716306 | Start2027 | PhaseNot applicable | ConditionsCancer | Participants60 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07710131 | Start2026 | PhaseNot applicable | ConditionsCancer | Participants36 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07652476 | Start2026 | PhaseObservational | ConditionsCancer | Participants100 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07638852 | Start2026 | PhasePhase 2 | ConditionsCancer | Participants58 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07633626 | Start2026 | PhaseObservational | ConditionsDepression and bipolar disorder, Cancer | Participants24 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07606313 | Start2026 | PhaseNot applicable | ConditionsCancer | Participants150 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07604246 | Start2026 | PhaseNot applicable | ConditionsCancer, Substance use and addiction | Participants25 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07587957 | Start2026 | PhaseNot applicable | ConditionsCancer | Participants40 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07586722 | Start2026 | PhaseNot applicable | ConditionsCancer | Participants32 | Lead sponsorOther | StatusActive, not recruiting | Library tests named
|
| NCT07585006 | Start2026 | PhasePhase 1 | ConditionsCancer, Substance use and addiction | Participants70 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07583979 | Start2026 | PhasePhase 3 | ConditionsCancer | Participants168 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07553481 | Start2026 | PhaseObservational | ConditionsCancer | Participants172 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07536178 | Start2026 | PhaseNot applicable | ConditionsCancer, Lung disease | Participants24 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07479927 | Start2025 | PhaseNot applicable | ConditionsCancer | Participants40 | Lead sponsorOther | StatusRecruiting | Library tests named
|
Questions, answered from the data
Which cognitive test do cancer trials use most?
Verbal Learning: 235 of the 760 registered studies name it in an outcome measure, 31%. Next come Verbal Fluency (200) and the Trail Making Test (187).
Which cognitive test do cancer trials use most as a primary outcome?
Verbal Learning, named in a primary outcome by 77 studies. 274 of the 760 studies, 36%, name a cognitive test in a primary outcome.
How many participants does a phase 2 cancer trial enroll?
Half of the phase 2 cancer studies enroll 60 participants or fewer, and the middle half enroll 30 to 112. 110 of them give a size.
How long after the start do cancer trials measure a cognitive outcome?
Half of the primary outcomes that name a library test are measured within 4 months of the start, and the middle half from 9 weeks to 12 months. 450 primary outcomes give a duration.
Which cognitive tests do cancer trials use together?
Verbal Fluency with Verbal Learning most often: 136 studies name both. Next, the Trail Making Test with Verbal Learning (121).
How many completed cancer trials have reported results?
135 of the 300 completed cancer studies, 45%, have reported results: 79 posted them on ClinicalTrials.gov, 87 have a results paper linked to the registry record, and 31 did both. The other 165 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.
How the studies are counted
For each test family, the census runs ClinicalTrials.gov's own outcome search for the family's names and reads every study first posted by the day the family was counted. These studies were read on 10 November 2026. A study counts once on a page, however many tests it names. Counts for a test cover every version of the task under any of its names, so a page can count studies that used a commercial version.
The census adds two things to each record and changes nothing in it: which outcome list names the test (primary, then secondary, then other), and the condition groups, matched on the study's condition names and MeSH terms. A study can fall in several groups; one whose only condition is cognitive impairment or decline falls in “Cognitive impairment and decline”. Studies that name only instruments outside the library count in every total and share but are not listed.
A second read on 10 November 2026 added each study's overall status, whether results are posted, its intervention types, the countries of its sites and the time frame of the outcome that names each test. A time frame counts by the latest time point it names: “Baseline, 12 and 24 weeks” is 24 weeks, a single visit is within a day, and one that names no duration, such as “end of treatment”, is left out of the timings.
A third read on 10 November 2026 added the papers the registry links to each study: those its sponsor lists as reporting results, and those PubMed links to it through the study's NCT number. A study has a results paper when one of them came out in or after the month of its primary completion and PubMed does not class it as a protocol, review or comment. A paper that never gives the NCT number is not linked, so some studies counted as reporting neither did publish.
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine, which does not endorse these pages. Every study line is in the data release 2.1.0, and the explorer's own file is clinical-trials-studies.json.
Plan the cognitive outcomes of a cancer trial
Choose tests with a record in registered trials, and run them in a browser at every site, on the same version each visit.