512 Background: The 70-gene expression profile (MammaPrint) is validated as an independent prognostic indicator for breast cancer patients with T1–2 node-negative and positive disease regardless of estrogen receptor status. Here we present the relationship between MammaPrint outcome and chemotherapy benefit in the adjuvant setting. Methods: We performed a pooled analysis of 1,637 patients with MammaPrint outcomes (T1–2, node-negative and positive invasive breast cancer and median FU 7.1 yrs) to determine the chemotherapy benefit of patients treated with adjuvant chemotherapy in addition to endocrine therapy. Patients were collected from 7 large datasets at multiple institutions across Europe. Results: In this meta-analysis, MammaPrint assigned 772 patients (47%) to “low risk” and 865 (53%) to “high risk”. In total 349 patients were treated with endocrine therapy alone, whereas 226 were treated with both chemo- and endocrine therapy. Patients with poor prognosis MammaPrint profile had a substantial benefit from chemotherapy: At 5 years, distant disease-free survival was improved from 69% to 88% (HR 0.28 (95% CI 0.14–0.56, p<0.001) when chemotherapy was added to hormonal therapy. The results remained significant in multivariate analysis including stratification by standard clinico-pathologic prognostic factors. Patients classified by MammaPrint as good prognosis (“low risk”) had no significant benefit from chemotherapy (p=0.962). Conclusions: The 70-gene MammaPrint profile is not only a strong and independent prognostic indicator for patients with early stage breast cancer, but it may also be predictive for the benefit of chemotherapy. While MammaPrint “high risk” classified patients demonstrate a clear benefit from adjuvant chemotherapy added to hormonal therapy, patients classified by MammaPrint as “low risk” for recurrence do not appear to benefit from the addition of chemotherapy to hormonal treatment alone. [Table: see text]
Factors affecting surgical margin positivity in invasive ductal breast cancer patients who underwent breast-conserving surgery after preoperative core biopsy diagnosis
