NEW YORK (GenomeWeb) – Researchers from NanoString Technologies and elsewhere have published a study in the Journal of Clinical Oncology showing that its PAM50-based Prosigna breast cancer test accurately predicts which patients with early stage, hormone receptor positive disease are at risk of late, distant recurrence after they've received five years of endocrine therapy.
The results from this study involving more than 2,000 postmenopausal breast cancer patients add to data from previously published investigations demonstrating the ability of Prosigna "to inform both the use of adjuvant chemotherapy and the use of extended adjuvant endocrine therapy based on a single risk score," the company said in a statement.
The study combined analysis of 2,137 postmenopausal women with hormone receptor-positive, early-stage breast cancer, who were previously enrolled in the Austrian Breast & Colorectal Cancer Study Group 8 (ABCSG-8) and Trans-Arimidex, Tamoxifen, Alone or in Combination (TransATAC) studies. The women received five years of endocrine treatment and didn't experience disease recurrence in the first five years after their diagnosis.
Researchers tested patients' samples on Prosigna to gauge whether the recurrence score could determine which patients would experience a recurrence beyond the first five years after diagnosis. The data showed that women that Prosigna deemed to be at high risk of recurrence had a 16.6 percent risk of distant recurrence, while those in the intermediate group had an 8.3 percent risk, and the low risk group had a 2.4 percent risk.
"It has been previously shown that the PAM50-based [recurrence] score is significantly correlated with distant recurrence in each of the TransATAC and ABCSG8 randomized trials," said lead study investigator Ivana Sestak from the Centre for Preventive Medicine at Queen Mary University in London. "In the combined analysis, the [recurrence] score significantly improved the accuracy of the prediction of the risk of late distant recurrence when compared to standard clinical and pathological variables in all patients and all subgroups."
Based on these results, NanoString further highlighted that Prosigna can identify the subset of patients where their risk of late, distant recurrence is so low that they can forgo additional hormonal treatment.
The American Society for Clinical Oncology recently updated its Cancer Treatment Guidelines to advise that most women should receive 10 years of endocrine therapy, noting that study data suggests that prolonged treatment is associated with better outcomes. The guidelines also note the need for strategies to better identify which women would most benefit from prolonged endocrine treatment.
NanoString presented data from this study at the San Antonio Breast Cancer Symposium last year.