Poor representation in breast-cancer clinical trials tied to real-world harms
NEW YORK 30/09 - Women with early breast cancer who are poorly represented in clinical trials experience poorer survival than their well-represented peers, according to a real-world analysis.
"These results highlight the need for increasing representation in clinical trials to reflect real-world disease populations and for evaluating outcomes for patients who are not well represented, in order to understand the best treatment options for patients," Jeffrey Franks of the University of Alabama at Birmingham said in a statement.
He presented the findings at the American Society of Clinical Oncology (ASCO) Quality Care Symposium, with simultaneous publication in JCO Oncology Practice.
"Clinical trials provide efficacy data to the (U.S. Food and Drug Administration) for the approval of new treatments. However, not all patient populations are adequately represented in these trials, which can result in patients receiving treatments that they were never properly tested for," Franks explained in his presentation.
He noted that over 240,000 women in the U.S. are diagnosed with early-stage breast cancer each year; 24% of these women are Black, indigenous or people of color; 44% are at age extremes, especially over the age of 70; and 32% have comorbidities. All of these groups are severely under-represented in clinical trials.
To better understand how representation status and clinical trials apply to real-world settings, Franks and colleagues identified 11,770 women diagnosed with early-stage breast cancer between 2005 and 2015 in ASCO's CancerLinQ database.
Patients with comorbidities or concurrent cancer, who made up 7% of the cohort, were considered unrepresented in clinical trials. Non-white patients and/or those aged younger than 45 or 70+, who made up 45% of the cohort, were considered under-represented, while patients who were white and aged 45 to 69 (48% of the cohort) were considered well-represented in clinical trials.
Compared with well-represented patients, there was almost a threefold increase in the risk of dying at five years in the unrepresented patients (adjusted hazard ratio, 2.71; 95% confidence interval, 2.08 to 3.52) and the results were similar by breast-cancer subtype, Franks reported.
There were no significant differences in the risk of five-year mortality for under-represented patients compared with well-represented patients (aHR, 1.19; 95% CI, 0.98 to 1.45), except for the hormone-receptor-positive/HER2-negative subtype, which had a 38% increase in the hazard of death (aHR, 1.38; 95% CI, 1.06 to 1.78).
Among the under-represented patients, the risk of five-year mortality was lower among those younger than 45 years (aHR, 0.63; 95% CI, 0.48 to 0.84) but higher among those age 70+ (aHR, 2.21; 95% CI, 1.76 to 2.77), compared with those in the well-represented age group of 45 to 69 years.
"Trialists should ensure study participants reflect the real-world disease population to support evidence-based decision making for all individuals with cancer," the study team says in their conference abstract.
In terms of recruiting to clinical trials, better outreach to under-represented populations would be helpful, Franks said. For unrepresented populations, ASCO and The Friends of Cancer Research recommend scenarios in which exclusion criteria can be removed.
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