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Accuracy of common prognostic signatures for breast cancer varies considerably
The accuracy of six prognostic signatures for ER-positive breast cancer varied widely in their ability to predict disease recurrence, according to results of a secondary analysis of a randomized clinical trial.
The Prosigna Breast Cancer Prognostic Gene Signature (NanoString Technologies), the Breast Cancer Index (Biotheranostics) and EndoPredict (Myriad Genetics) appeared significantly more prognostic than the other signatures evaluated for overall and late distant recurrence of node-negative disease, results showed.
All six multigene signatures provided limited independent information for women with one to three positive nodes.
“Being able to accurately predict the risk [for] breast cancer recurrence is even more important now that we are in an era where women are prescribed preventive endocrine therapy for many years,” Ivana Sestak, Ms, PhD, lecturer in medical statistics in the Centre for Cancer Prevention within Wolfson Institute of Preventive Medicine at Queen Mary University of London, said in a press release. “If we were better able to accurately assess a woman’s long-term risk, then some women may be able to end their endocrine therapy after 5 years, but for those deemed [at] high risk [for] a late recurrence, continuing their endocrine therapy would be a valuable option.”
Prognostic tests have increased the ability to predict which patients with ER-positive breast cancer remain at high risk for distant recurrence; however, little long term direct comparative information is available.
Sestak and colleagues retrospectively analyzed data from 774 postmenopausal women with ER-positive, ERBB2-negative breast cancer. Mean age was 64.1 years, and 591 women had node-negative disease.
Researchers compared four multigene tests — Oncotype Dx (Genomic Health), Prosigna Breast Cancer Prognostic Gene Signature, Breast Cancer Index and EndoPredict — as well as a clinical treatment score and a four-marker immunohistochemical score.
“This is the first time that anyone has directly compared the prognostic performance of these four common commercially-available tests,” Sestak said. “This gives clinicians and oncologists the opportunity to review all the results and decide upon the test they want to use.”
Researchers collected follow-up data from January 2009 to April 2015.
A comparison of the prognostic value of the tests in addition to the clinical treatment score for distant recurrence at 0 to 10 years after diagnosis, as well as 5 to 10 years after diagnosis, served as the primary endpoint.
All six signatures provided a statistically significant prognostic value for distant recurrence from 0 to 10 years after diagnosis. The signatures performed similarly from 0 to 5 years after diagnosis.
“We found differences during years 5 to 10, when these tests may be valuable for decision making with regard to extended endocrine treatment,” Sestak and colleagues wrote.
The Prosigna test yielded the most prognostic information (HR = 2.65; 95% CI, 1.96-3.35), followed by the Breast Cancer Index (HR = 2.46; 95% CI, 1.88-3.23), EndoPredict (HR = 2.14; 95% CI, 1.71-2.68), the clinical treatment score (HR = 1.99; 95% CI, 1.58-2.5), Oncotype DX (HR = 1.69; 95% CI, 1.4-2.03) and the four-marker immunohistochemical score (HR = 1.95; 95% CI, 1.55-2.45).
All six tests provided considerably less information for the 183 patients with one to three positive nodes. The Breast Cancer Index and EndoPredict provided more additional prognostic information than the other signatures, researchers wrote.
Sestak and colleagues acknowledged the study was limited by results that were only applicable to chemotherapy-free and postmenopausal women. – by Melinda Stevens
Disclosures: Sestak reports speaker fees from Myriad Genetics. Please see the full study for a list of all other authors’ relevant financial disclosures.