# Close the gap between who gets triple-negative breast cancer and who is in its trials

Source: https://onco.cc/ideas/idea-tnbc-disparities-in-access-and-outcomes/  
OnCo record `idea-tnbc-disparities-in-access-and-outcomes` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Black women in the United States have about twice the odds of a triple-negative diagnosis and, in the UK POSH cohort, worse survival than White women despite equal chemotherapy use. The pivotal trials enrolled few of them. Enrolment targets tied to incidence, reported by ethnicity in every primary paper, would make the evidence match the disease.

## Summary

The Carolina Breast Cancer Study found basal-like tumours in 39 percent of premenopausal African American women against 16 percent of others; the US Cancer Statistics analysis of 1.15 million cases gave non-Hispanic Black women an odds ratio of 2.27 for triple-negative diagnosis; California registry data showed five-year relative survival of 14 percent for Black women with late-stage disease. In the UK, POSH found 26.1 percent triple-negative disease in Black women under 41 against 18.6 percent in White women and five-year survival of 71.1 versus 82.4 percent with chemotherapy use equal at 89 percent, so access alone does not explain the gap. The pivotal immunotherapy and antibody-drug conjugate trials report ethnicity, where they report it, in single digits for Black participants. Whether biology (BRCA1 founder variants, subtype distribution, immune environment) or care (time to treatment, dose delivery, trial access) drives the outcome gap is unresolved because the data to separate them are not collected.

## Fields

- Kind: Idea
- Last checked: 2026-09-24
- Tags: tnbc-evidence
- Hypothesis: Requiring phase 3 triple-negative breast cancer trials to set enrolment targets for Black and Hispanic participants proportional to incidence in the enrolling countries, and to report efficacy and toxicity by ethnicity in the primary publication, will within five years show whether treatment effects differ by ancestry and will halve the enrolment gap without slowing accrual.
- Rationale: Under-representation means the drugs that now define standard care were tested largely in the population least affected; disparities in incidence are established and in outcome persist under equal access, so ancestry-stratified evidence is a scientific need as well as an equity one.
- Proposed test: Audit of ethnicity enrolment and reporting in every phase 3 triple-negative trial since 2015 as baseline; a regulator- or funder-mandated enrolment plan for new trials with pre-specified ancestry subgroups; a UK cohort linking ethnicity, germline status, subtype, treatment delivery and outcome through national registry and NHS data.
- Maturity: speculative
- Actor: policy

## Sources

- Scott et al.: triple-negative breast cancer disparities in the United States, 2010 to 2014 (Cancer 2019): https://europepmc.org/article/MED/31282032
- Copson et al.: POSH, ethnicity and outcome in young UK breast cancer patients (Br J Cancer 2014): https://europepmc.org/article/MED/24149174

## Connected records

- ideas: [A UK audit of trial access and germline testing uptake in triple-negative breast cancer](https://onco.cc/ideas/idea-tnbc-uk-trial-access-and-germline-testing-audit/), [Ethnicity-stratified outcome reporting for triple-negative breast cancer in NHS cancer statistics](https://onco.cc/ideas/idea-tnbc-uk-ethnicity-stratified-outcome-reporting/)
- cancers: [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- technologies: [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/)
- bottlenecks: [Fragmented care and guideline gaps](https://onco.cc/bottlenecks/b-care-fragmentation/), [Most of the world has almost no cancer care](https://onco.cc/bottlenecks/b-global-access/), [Trials do not represent the people who get cancer](https://onco.cc/bottlenecks/b-trial-diversity/)
- key papers: [Descriptive analysis of estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and HER2-negative invasive breast cancer, the so-called triple-negative phenotype: a population-based study from the California cancer Registry](https://onco.cc/key-papers/paper-bauer-triple-negative-california-registry-cancer-2007/), [Ethnicity and outcome of young breast cancer patients in the United Kingdom: the POSH study](https://onco.cc/key-papers/paper-copson-posh-ethnicity-young-breast-cancer-uk-bjc-2014/), [Race, breast cancer subtypes, and survival in the Carolina Breast Cancer Study](https://onco.cc/key-papers/paper-carey-race-breast-cancer-subtypes-cbcs-jama-2006/), [Update on triple-negative breast cancer disparities for the United States: A population-based study from the United States Cancer Statistics database, 2010 through 2014](https://onco.cc/key-papers/paper-scott-tnbc-disparities-uscs-cancer-2019/), [US incidence of breast cancer subtypes defined by joint hormone receptor and HER2 status](https://onco.cc/key-papers/paper-howlader-us-incidence-breast-subtypes-jnci-2014/)
- roadmaps: [Triple-negative breast cancer roadmap: from a remainder defined by three negative tests to immunotherapy, antibody-drug conjugates and the residual disease problem](https://onco.cc/roadmaps/tnbc-roadmap/)

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