Identification of a low-risk subgroup of HER-2-positive breast cancer by the 70-gene prognosis signature.
Bottom Line: However, the majority of patients does not recur and might thus be overtreated with adjuvant systemic therapy.We investigated whether the 70-gene MammaPrint signature identifies HER-2-positive patients with favourable outcome. in all, 168 T1-3, N0-1, HER-2-positive patients were identified from a pooled database, classified by the 70-gene signature as good or poor prognosis, and correlated with long-term outcome.The 70-gene signature classified 20 (22%) patients as good prognosis, with 10-year distant disease-free survival (DDFS) of 84%, compared with 69 (78%) poor prognosis patients with 10-year DDFS of 55%.
Affiliation: Division of Diagnostic Oncology, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, Amsterdam NL-1066CX, The Netherlands.Show MeSH
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Mentions: An exploratory subgroup analysis was performed according to the degree of hormonal receptor expression in this group of patients with HER-2-positive disease. To explore whether expression of hormonal receptors identified a subgroup of HER-2-positive/70-gene profile low-risk tumours with a particularly favourable outcome, we separately analysed the 40 out of 168 patients (24%) with HER-2 overexpression that were highly endocrine responsive (see Kaplan–Meier curves in Figure 3A). In all, 21 out of these 40 patients did not receive adjuvant chemotherapy, shown in Figure 3B. According to the 2007 St. Gallen consensus conference, ‘highly endocrine responsive' tumours express high levels of both steroid hormone receptors in a majority of cells (Goldhirsch et al, 2007). For this analysis, IHC staining of both ER and PR in 50% or more of cells were considered ‘highly endocrine-responsive'. Within this subgroup, no distant metastases or breast cancer-specific deaths were observed in the patients with a 70-gene profile ‘good prognosis' testing result (11 out of 40; 28%). Figure 3A depicts the survival curves for the 40 highly endocrine-responsive patients and Figure 3B shows 10-year DDFS and BCSS for the 21 chemotherapy-naive patients within this subgroup.
Affiliation: Division of Diagnostic Oncology, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, Amsterdam NL-1066CX, The Netherlands.