The 21-gene assay in early-stage breast cancer

The prognosis of early stage estrogen receptor positive breast cancer is generally very good and the average benefit of adding adjuvant chemotherapy to adjuvant endocrine therapy is small but exists. The 21-gene recurrence score (RS) assay has been validated through the use of retrospective studies as prognostic of distant disease recurrence and predictive of the benefit of adding chemotherapy. We evaluated the impact of using the test in our practice, a university based group of oncologists who have a uniform treatment policy. For a high risk RS, chemotherapy was recommended, for a low risk, endocrine therapy alone and for intermediate risk, treatment based on traditional clinicopathologic factors with help from Adjuvant!on-line. In this retrospective analysis of 135 patients whom we tested with the 21-gene RS between 2006- 2009, in 25 % of patients we changed recommendation after obtaining results. Most changes were in the direction of not giving chemotherapy (70% of changes). A somewhat surprising finding was that 29 % of the 49 patients for whom we recommended chemotherapy after obtaining the RS, refused chemotherapy. The RS substantially reduced the number of patients receiving chemotherapy but we need to improve our patients' understanding of the implications of the test.   

Bibliographic Reference:

Geffen DB et al.: "The impact of the 21-gene recurrence score assay on decision making about adjuvant chemotherapy in early-stage estrogen-receptor-positive breast cancer in an oncology practice with a unified treatment policy", Ann Oncol. 2011 Mar 1. [Epub ahead of print]

David B. Geffen
Department of Oncology, Soroka University Medical Center and the Faculty of Health Sciences, Ben Gurion University of the Negev. Beer Sheva, Israel