Among women with estrogen-receptor positive breast cancer, late recurrence was best predicted by the clinical treatment score. Significant prognostic value was added by the PAM50 risk of recurrence score and by the Breast Cancer Index score, according to a study comparing five scores that was presented at the 5th IMPAKT Breast Cancer Conference in Brussels, Belgium.
Among women whose cancer is estrogen-receptor positive, half of all recurrences will occur after the women finish the standard five years of hormonal treatment, explained lead author Ivana Sestak, PhD, of the Wolfson Institute of Preventive Medicine in London, UK.
“There is great interest in establishing which women are at adequate high risk of late recurrence after the initial hormonal treatment period, which is currently 5 years,” said Sestak.
The ATAC trial included nearly 10,000 women who were treated with surgery followed by five years of anastrozole, tamoxifen, or a combination of both. The transATAC study included 1,125 of these women from the monotherapy arms (either anastrozole or tamoxifen).
The study compared five scores. The clinical treatment score, which includes information on the patient’s disease and treatments so far, was best for predicting late recurrence. The PAM50 risk of recurrence score and the Breast Cancer Index score, which are both gene expression scores, added the most significant prognostic value between years 5 and 10 after diagnosis. The other two scores included in the comparison were the IHC4 score, which characterizes the presence of cell surface markers on cancer cells, and the Oncotype DX Recurrence Score, which is a gene expression score.
“The most promising new scores from this study are the PAM50 Risk of Recurrence score and the Breast Cancer Index score, both containing different genetic information that is not included in the clinical treatment score and at the moment is not routinely measured in clinics,” said Sestak.
“Our further interest now lies in the investigation of which individual components of these scores attribute specifically to the prediction of late recurrence, since the Risk of Recurrence and Breast Cancer Index scores consist of several genes and other components. We are now undertaking these analyses and the results will hopefully tell us which genes specifically predict late recurrence. However, at this stage it is not possible to predict response to treatment.”