The following article features coverage from the 2021 ASCO Quality Care Symposium. Click here to read more of Cancer Therapy Advisor’s conference coverage.

Patients with early breast cancer who are not represented in clinical trials have an increased risk of mortality at 5 years, a new study suggests.

The data also indicate that certain patients who are underrepresented in trials have an increased risk of death, whereas other underrepresented patients have similar outcomes as patients who are well-represented.

These findings were presented at the 2021 American Society of Clinical Oncology (ASCO) Quality Care Symposium1 and published simultaneously in JCO Oncology Practice.2

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The study included 11,770 patients from the CancerLinQ Discovery database who were diagnosed with early-stage breast cancer between 2005 and 2015 and received 1 of 7 common chemotherapy regimens.

The cohort included 5624 patients (48%) who were considered well-represented in clinical trials. Well-represented patients were White, aged 45 to 69 years, and did not have any comorbidities or a concurrent cancer.

There were 5267 underrepresented patients (45%). This group included Black and Indigenous people of color, patients younger than 45 years of age, and patients age 70 or older.

The remaining 879 patients (7%) were categorized as unrepresented in trials. These patients had comorbidities or concurrent cancers.

Survival Outcomes

The unrepresented patient population had a significantly increased risk of death at 5 years compared with the well-represented population (hazard ratio [HR], 2.71; 95% CI, 2.08-3.52).

This was true for all breast cancer subtypes, including HER2-positive breast cancer (HR, 2.50; 95% CI, 1.39-4.48), hormone receptor-positive and HER2-negative breast cancer (HR, 2.54; 95% CI, 1.75-3.68), and triple-negative disease (HR, 2.75; 95% CI, 1.68-4.50).

Overall, patients who were underrepresented in clinical trials had a similar risk of death at 5 years as patients who were well-represented (HR, 1.19; 95% CI, 0.98-1.45).

The risk was similar between underrepresented and well-represented groups for patients with HER2-positive or triple-negative disease. However, among patients with hormone-receptor-positive and HER2-negative disease, the underrepresented group had a significantly higher risk of death (HR, 1.38; 95% CI, 1.06-1.78).

Disclosures: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Read more of Cancer Therapy Advisor’s coverage of ASCO QCS 2021 by visiting the conference page.


  1. Franks J, Gidwani R, Enogela EM, et al. Survival in the real world: A national analysis of patients treated for early-stage breast cancer. J Clin Oncol. 2021;39:(suppl 28; abstr 75). doi: 10.1200/JCO.2020.39.28_suppl.075
  2. Gidwani R, Franks JA, Enogela EM, et al. Survival in the real world: A national analysis of patients treated for early-stage breast cancer. JCO Oncol Pract. Published online September 24, 2021. doi:10.1200/OP.21.00274