# Trials enrol too few, too slowly

Source: https://onco.cc/bottlenecks/b-trial-enrolment/  
OnCo record `b-trial-enrolment` (Bottleneck). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Fewer than one in ten adults with cancer joins a trial. Trials close for lack of patients, not lack of ideas.

## Summary

Around 8% of adults with cancer participate in a treatment trial, and a fifth of trials fail to complete, most often for poor accrual. The barriers are structural before they are personal: most patients are treated at community practices with no open trial, eligibility criteria exclude patients with brain metastases, organ dysfunction, prior cancers or HIV, travel and time costs fall on patients, and physicians have no time or incentive to screen and refer. When a trial is actually offered, more than half of patients say yes. Slow accrual lengthens trials, raises costs, delays answers and kills questions that industry will not fund. Broadened eligibility, decentralised and community-based trial infrastructure, automated matching from the electronic record, and paying patients' costs are the fixes with evidence.

## Fields

- Kind: Bottleneck
- Last checked: 2026-09-08
- Stage: trials
- Severity: critical
- Metrics: Adults with cancer participating in treatment trials (US, meta-analysis): ~8% (Unger et al., JNCI 2019); Patients who agree to participate when a trial is offered to them: 55% (Unger et al., JNCI 2021); Adult cancer trials in ClinicalTrials.gov that failed to complete, most often for poor accrual: ~20% (Stensland et al., JNCI 2014)
- Causes: Most patients are treated in community settings where no relevant trial is open.; Restrictive eligibility criteria exclude a large share of real patients for reasons unrelated to safety.; Travel, lost income and out-of-pocket costs fall on patients and are rarely reimbursed.; Physicians lack time, incentives and tools to identify eligible patients.; Trial activation takes months per site because of contracting and ethics review, so windows of opportunity close.

## Sources

- Unger et al., Systematic review of barriers to cancer trial participation (JNCI 2019): https://doi.org/10.1093/jnci/djy221
- Kim et al., Broadening eligibility criteria to make clinical trials more representative (JCO 2017): https://doi.org/10.1200/JCO.2017.73.7916
- NCI Community Oncology Research Program: https://ncorp.cancer.gov/

## Connected records

- collections: [ClinicalTrials.gov](https://onco.cc/collections/clinicaltrials-gov/), [EU Clinical Trials Register / CTIS](https://onco.cc/collections/eudract-ctis/)
- ideas: [A global first-in-human network for academic cancer trials with single ethics review](https://onco.cc/ideas/idea-fund-global-academic-phase-one-network/), [A global open trials operating system any hospital can plug into](https://onco.cc/ideas/idea-moon-global-open-trials-os/), [A live 'seats available' feed for trial slots, like airline inventory](https://onco.cc/ideas/idea-tr1-live-trial-slot-api/), [A mandatory trial line in every tumour board recommendation](https://onco.cc/ideas/idea-tr1-tumour-board-trial-line-item/), [A national platform trial that every ctDNA-positive patient can join](https://onco.cc/ideas/idea-bio2-national-mrd-platform/), [A permanently funded international network for randomised cancer surgery trials](https://onco.cc/ideas/idea-fund-surgical-trials-network/), [A public map of trial deserts to steer where new sites open](https://onco.cc/ideas/idea-tr1-trial-desert-map/), [A randomised trial of adjuvant chemoradiation after margin-positive or node-positive gallbladder cancer resection](https://onco.cc/ideas/idea-gbc-randomised-adjuvant-chemoradiation-r1-node-positive/), [A shared library of pooled control arms to shrink and speed future trials](https://onco.cc/ideas/idea-fund-control-arm-commons/), [A standing platform trial for every major cancer, funded as infrastructure](https://onco.cc/ideas/idea-tr1-standing-platform-per-cancer/), [A standing platform trial that assigns treatment by how the tumour escaped](https://onco.cc/ideas/idea-bio1-resistance-platform-trial/), [An asynchronous expert second opinion for every new advanced-cancer diagnosis](https://onco.cc/ideas/idea-acc-universal-asynchronous-second-opinion/), [At least a third of pivotal-trial sites in community and rural settings](https://onco.cc/ideas/idea-tr1-community-site-quota/), [Borrow from past control arms to shrink the control group in phase 3](https://onco.cc/ideas/idea-tr1-bayesian-borrowing-smaller-controls/), [Brain metastases included by default in every solid-tumour trial](https://onco.cc/ideas/idea-tr1-brain-mets-default-included/), [Bring the oncologist to the local clinic by video and the drug to the local pharmacy](https://onco.cc/ideas/idea-cost-travel-teleoncology/), [Broad research consent as a routine step of the cancer pathway](https://onco.cc/ideas/idea-data-consent-in-the-pathway/), [Chemotherapy before the second operation for high-risk incidental gallbladder cancer](https://onco.cc/ideas/idea-gbc-neoadjuvant-for-high-risk-incidental-cancer/), [Community health workers and trusted local organisations paid to recruit for trials](https://onco.cc/ideas/idea-tr1-community-health-worker-recruitment/), [Competing sponsors share one control arm in the same indication](https://onco.cc/ideas/idea-tr1-shared-control-arms-across-sponsors/), [Default-inclusive eligibility: sponsors must justify every exclusion criterion](https://onco.cc/ideas/idea-tr1-justify-every-exclusion/), [Drop mandatory fresh biopsies where blood or archival tissue would do](https://onco.cc/ideas/idea-tr1-drop-non-essential-biopsies/), [Drop the 'must speak English' rule: translated consent and questionnaires as standard](https://onco.cc/ideas/idea-tr1-language-access-in-trials/), [Evening and weekend trial clinics for working-age patients](https://onco.cc/ideas/idea-tr1-evening-weekend-trial-clinics/), [Every patient is asked once at diagnosis whether researchers may contact them](https://onco.cc/ideas/idea-tr1-opt-out-research-contact-register/), [Every payer covers routine care costs for trial participants, in every country](https://onco.cc/ideas/idea-tr1-universal-routine-cost-coverage/), [Every tumour sequencing report lists open, nearby, matched trials pulled live](https://onco.cc/ideas/idea-tr1-ngs-report-live-trial-match/), [Fix the neutrophil count rule that excludes many people of African ancestry](https://onco.cc/ideas/idea-tr1-duffy-null-neutrophil-threshold/), [Guidelines list the open trials at every decision point, updated monthly](https://onco.cc/ideas/idea-tr1-open-trials-inside-guidelines/), [Home infusion and local blood draws for trial drugs after the first cycles](https://onco.cc/ideas/idea-tr1-home-infusion-trial-drugs/), [Just-in-time site activation: open a site in two weeks when a patient appears](https://onco.cc/ideas/idea-tr1-just-in-time-site-network/), [Kidney and liver impairment dosing studies completed before approval, not years after](https://onco.cc/ideas/idea-tr1-organ-impairment-pk-before-approval/), [Lay trial navigators funded per centre, evaluated in a randomised trial](https://onco.cc/ideas/idea-tr1-lay-trial-navigators/), [Mobile research units bring trial visits to rural towns](https://onco.cc/ideas/idea-tr1-mobile-research-units/), [Mutual recognition of ethics review across countries](https://onco.cc/ideas/idea-tr1-mutual-recognition-ethics-review/), [One clinical trial application accepted by regulators in every major region](https://onco.cc/ideas/idea-reg-global-trial-application-portal/), [One national master contract and budget template for all cancer trials](https://onco.cc/ideas/idea-tr1-national-master-trial-agreement/), [One standing umbrella trial for all rare cancers in a country](https://onco.cc/ideas/idea-bio2-rare-cancer-umbrella-platform/), [Patients are told which trials they qualify for at every treatment decision, in writing](https://onco.cc/ideas/idea-moon-trial-eligibility-at-every-decision/), [Pay investigators for finishing and publishing trials, not for enrolling patients](https://onco.cc/ideas/idea-fund-trial-completion-bonus/), [Pay oncologists for the time it takes to enrol a patient](https://onco.cc/ideas/idea-tr1-protected-physician-time-for-enrolment/), [Pay trial participants for their time, not only their expenses](https://onco.cc/ideas/idea-tr1-pay-participants-for-time/), [Point-of-care randomisation built into the oncology record](https://onco.cc/ideas/idea-data-point-of-care-randomisation/), [Pragmatic trials in patients over 75 with function, not just survival, as the primary endpoint](https://onco.cc/ideas/idea-acc-pragmatic-trials-over-75-function-endpoints/), [Pre-consented cohorts that can be randomised to future trials (TwiCs)](https://onco.cc/ideas/idea-tr1-pre-consented-cohort-randomisation/), [Publish why patients were screened out of each trial](https://onco.cc/ideas/idea-tr1-public-screen-fail-reasons/), [Randomise inside the cancer registry: registry-based trials for everyday questions](https://onco.cc/ideas/idea-tr1-registry-embedded-randomisation/), [Randomised evidence for the T-cell lymphomas, including the ones that are not in Europe or North America](https://onco.cc/ideas/lymphoma-ev-randomised-evidence-for-the-t-cell-lymphomas/), [Registry-based randomised MCED trial: a million people, no study visits](https://onco.cc/ideas/idea-prev-mced-registry-randomised/), [Registry-based randomised trials for oncology comparative effectiveness](https://onco.cc/ideas/idea-data-registry-based-rcts/), [Remote consent and tele-screening so the first trial visit is a video call](https://onco.cc/ideas/idea-tr1-remote-consent-tele-screening/), [Remove blanket exclusions for mental illness and dementia; support consent instead](https://onco.cc/ideas/idea-tr1-disability-and-mental-illness-inclusion/), [Replace fixed kidney and liver cut-offs with drug-specific, pharmacology-based thresholds](https://onco.cc/ideas/idea-tr1-pk-informed-organ-thresholds/), [Run small-cell lung cancer as one platform with shared controls and subtype stratification](https://onco.cc/ideas/idea-lung-small-cell-platform-with-shared-controls-and-subtypes/), [Set trial enrolment targets from who actually gets the disease, and publish progress live](https://onco.cc/ideas/idea-tr1-incidence-weighted-enrolment-targets/), [Shared concurrent control arms across sponsors' trials in the same setting](https://onco.cc/ideas/idea-tr2-shared-control-network/), [Simulate eligibility against real-world data before every protocol is locked](https://onco.cc/ideas/idea-tr1-eligibility-impact-statement/), [Stop excluding brain metastases from cancer trials](https://onco.cc/ideas/idea-bio2-cns-cohort-mandate/), [Stop excluding people with a prior cancer, controlled HIV, or treated hepatitis](https://onco.cc/ideas/idea-tr1-prior-cancer-hiv-hepatitis-inclusion/), [Stop over-excluding people who could become pregnant; study pregnancy exposure](https://onco.cc/ideas/idea-tr1-include-pregnancy-capable-people-sensibly/), [The pathology lab triggers a trial referral the day a rare cancer is diagnosed](https://onco.cc/ideas/idea-tr1-pathology-triggered-referral/), [Travel, lodging and meals reimbursed as a standard line in every trial budget](https://onco.cc/ideas/idea-tr1-travel-lodging-in-every-budget/), [Treat trial enrolment as a cost lever: the sponsor pays for the drug](https://onco.cc/ideas/idea-cost-trial-enrolment-cost-lever/), [Trial matching inside the electronic record at the moment a treatment is chosen](https://onco.cc/ideas/idea-tr1-ehr-point-of-care-trial-alert/), [Trial-in-a-box: a preconfigured protocol kit any hospital can open for a rare cancer](https://onco.cc/ideas/idea-tr1-rare-cancer-trial-in-a-box/), [Two-page plain-language consent with teach-back for every cancer trial and treatment](https://onco.cc/ideas/idea-moon-plain-language-consent/)
- technologies: [AI trial matching & clinical decision support](https://onco.cc/technologies/ai-trial-matching/)
- companies: [Alliance for Clinical Trials in Oncology](https://onco.cc/companies/alliance-oncology/), [Canadian Cancer Trials Group (CCTG)](https://onco.cc/companies/cctg/), [ECOG-ACRIN Cancer Research Group](https://onco.cc/companies/ecog-acrin/), [Innovative Therapies for Children with Cancer (ITCC)](https://onco.cc/companies/itcc/), [Japan Clinical Oncology Group (JCOG)](https://onco.cc/companies/jcog/), [NRG Oncology](https://onco.cc/companies/nrg-oncology/), [SWOG Cancer Research Network](https://onco.cc/companies/swog/), [Tempus AI](https://onco.cc/companies/tempus/), [UNICANCER](https://onco.cc/companies/unicancer/)
- institutions: [American Society of Clinical Oncology (ASCO)](https://onco.cc/institutions/asco/), [Canadian Cancer Society](https://onco.cc/institutions/canadian-cancer-society/), [City of Hope Orange County](https://onco.cc/institutions/city-of-hope-orange-county/), [HL7 International](https://onco.cc/institutions/hl7/), [Institut National du Cancer](https://onco.cc/institutions/inca/), [Irish Cancer Society](https://onco.cc/institutions/irish-cancer-society/), [National Cancer Institute (NIH)](https://onco.cc/institutions/nci/), [Northwell Health Cancer Institute](https://onco.cc/institutions/northwell-cancer-institute/), [The Ottawa Hospital Cancer Centre / Ottawa Hospital Research Institute](https://onco.cc/institutions/ottawa-hospital/), [The University of Kansas Cancer Center](https://onco.cc/institutions/ku-cancer-center/)
- terms: [Basket trial](https://onco.cc/terms/basket-trial/), [Basket, umbrella, and platform trials](https://onco.cc/terms/basket-umbrella-platform/), [China Human Genetic Resources rules (2019, 2023)](https://onco.cc/terms/china-hgr-rules/), [Clinical Trials Regulation (EU) No 536/2014 and CTIS](https://onco.cc/terms/eu-clinical-trials-regulation/), [Decentralised trial](https://onco.cc/terms/decentralised-trial/), [Declaration of Helsinki](https://onco.cc/terms/declaration-of-helsinki/), [Expanded access (compassionate use)](https://onco.cc/terms/expanded-access/), [ICH good clinical practice (E6)](https://onco.cc/terms/ich-gcp/), [Informed consent](https://onco.cc/terms/informed-consent/), [Master protocol (platform, basket and umbrella trials)](https://onco.cc/terms/master-protocol/), [Pragmatic trial](https://onco.cc/terms/pragmatic-trial/), [Registry-based randomised trial](https://onco.cc/terms/registry-based-trial/), [Right to Try Act 2018 and state right-to-try laws](https://onco.cc/terms/right-to-try/), [Standard of care](https://onco.cc/terms/standard-of-care/), [The Common Rule (45 CFR 46)](https://onco.cc/terms/common-rule/), [Trial lifecycle: from protocol to label](https://onco.cc/terms/trial-lifecycle/), [Umbrella trial](https://onco.cc/terms/umbrella-trial/)
- key papers: [AGILE: ivosidenib plus azacitidine for newly diagnosed IDH1-mutated AML in patients unfit for intensive chemotherapy](https://onco.cc/key-papers/paper-agile-ivosidenib-azacitidine-nejm-2022/), [Anaplastic lymphoma kinase inhibition in non-small-cell lung cancer](https://onco.cc/key-papers/paper-kwak-crizotinib-alk-nsclc-nejm-2010/), [Broadening Eligibility Criteria to Make Clinical Trials More Representative: American Society of Clinical Oncology and Friends of Cancer Research Joint Research Statement](https://onco.cc/key-papers/paper-kim-j-clin-oncol/), [Dual-targeted therapy with trastuzumab and lapatinib in treatment-refractory, KRAS codon 12/13 wild-type, HER2-positive metastatic colorectal cancer (HERACLES)](https://onco.cc/key-papers/paper-sartore-bianchi-heracles-trastuzumab-lapatinib-lancet-oncol-2016/), [Final results of the IELSG-19 randomized trial of mucosa-associated lymphoid tissue lymphoma: improved event-free and progression-free survival with rituximab plus chlorambucil versus either chlorambucil or rituximab monotherapy](https://onco.cc/key-papers/paper-ielsg-19-chlorambucil-rituximab-malt-jco-2017/), [GETUG-AFU 15: androgen deprivation alone or with docetaxel in non-castrate metastatic prostate cancer](https://onco.cc/key-papers/paper-gravis-getug-afu-15-docetaxel-lancet-oncol-2013/), [Neoadjuvant chemotherapy with gemcitabine plus cisplatin followed by radical liver resection versus immediate radical liver resection alone with or without adjuvant chemotherapy in incidentally detected gallbladder carcinoma after simple cholecystectomy or in front of radical resection of BTC (ICC/ECC) - a phase III study of the German registry of incidental gallbladder carcinoma platform (GR)- the AIO/ CALGP/ ACO- GAIN-trial](https://onco.cc/key-papers/paper-gain-trial-protocol-bmc-cancer-2020/), [Paclitaxel-carboplatin alone or with bevacizumab for non-small-cell lung cancer](https://onco.cc/key-papers/paper-sandler-ecog-4599-bevacizumab-nsclc-nejm-2006/), [PIVOT: follow-up of prostatectomy versus observation for early prostate cancer](https://onco.cc/key-papers/paper-wilt-pivot-prostatectomy-observation-nejm-2017/), [Randomized trial of systemic therapy after involved-field radiotherapy in patients with early-stage follicular lymphoma: TROG 99.03](https://onco.cc/key-papers/paper-trog-99-03-radiotherapy-systemic-therapy-early-follicular-jco-2018/), [TRITON3: rucaparib or physician's choice in metastatic castration-resistant prostate cancer](https://onco.cc/key-papers/paper-fizazi-triton3-rucaparib-nejm-2023/), [Unger: most patients never get the chance to join a cancer trial, and when offered, half say yes](https://onco.cc/key-papers/paper-unger-trial-participation-barriers-jnci-2019/)
- roadmaps: [Gallbladder cancer roadmap: from a chance finding at gallstone surgery to a disease with its own trials](https://onco.cc/roadmaps/gallbladder-cancer-roadmap/), [Paediatric oncology roadmap: cooperative-group cures → engineered immunity → drugs developed for children first](https://onco.cc/roadmaps/paediatric-oncology-roadmap/), [Trial modernisation roadmap: the randomised trial → platforms and adaptive designs → decentralised, pragmatic and always-on](https://onco.cc/roadmaps/trial-modernisation-roadmap/)
- trials: [IELSG-19](https://onco.cc/trials/ielsg-19/), [JCOG9801](https://onco.cc/trials/jcog9801/), [Mosunetuzumab with lenalidomide in relapsed marginal zone lymphoma](https://onco.cc/trials/mosun-len-mzl/), [National Lung Matrix Trial](https://onco.cc/trials/national-lung-matrix-trial/), [POLAR BEAR](https://onco.cc/trials/polar-bear/), [TARGET National](https://onco.cc/trials/target-national/)
- people: [Barbara Bradfield](https://onco.cc/people/barbara-bradfield/), [Bud Romine](https://onco.cc/people/bud-romine/), [Emily Whitehead](https://onco.cc/people/emily-whitehead/), [Robert Sandler](https://onco.cc/people/robert-sandler/), [Sharon Belvin](https://onco.cc/people/sharon-belvin/), [Susan Love](https://onco.cc/people/susan-love/)
- cancers: [Ampullary cancer (ampulla of Vater)](https://onco.cc/cancers/ampullary/), [Rare cancers of childhood (NCI PDQ umbrella)](https://onco.cc/cancers/rare-childhood-cancers/), [Small intestine cancer (small bowel adenocarcinoma)](https://onco.cc/cancers/small-bowel/)

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