Triple-negative high-risk breast cancer derives particular benefit from dose intensification of adjuvant chemotherapy: results of WSG AM-01 trial.

Author(s): Gluz O, Nitz UA, Harbeck N, Ting E, Kates R, Herr A, Lindemann W, Jackisch C, Berdel WE, Kirchner H, Metzner B, Werner F, Schutt G, Frick M, Poremba C, Diallo-Danebrock R, Mohrmann S, West German Study Group

Affiliation(s): West German Study Group, Breast Centre, Department of Gynecology and Obstetrics, University Hospital of Duesseldorf, Moorenstrasse 5, 40225 Duesseldorf, Germany. oleg.gluz@wsg-online.com

Publication date & source: 2008-05, Ann Oncol., 19(5):861-70. Epub 2008 Jan 3.

Publication type:

BACKGROUND: This paper evaluates the prognostic and predictive impact of protein expression of various molecular markers in high-risk breast cancer (HRBC) patients with >9 involved lymph nodes, who received different chemotherapy dose-intensification strategies within a prospective randomized WSG AM-01 trial. MATERIALS AND METHODS: Paraffin-embedded tumors from 236 patients, who were randomly assigned to dose-dense conventional chemotherapy with four cycles of E(90)C(600) followed by three cycles of C(600)M(40)F(600) every 2 weeks (DD) or a rapidly cycled tandem high-dose regimen with two cycles of E(90)C(600) every 2 weeks followed by two cycles of E(90)C(3000)Thiotepa(400) every 3 weeks (HD), were available for retrospective central pathological review (116 HD/120 DD). Expression of estrogen receptor (ER), progesterone receptor (PR), MIB-1, epidermal growth factor receptor, and Her-2/neu was evaluated immunohistochemically using tissue microarrays. Results were correlated with follow-up data and treatment effects by proportional hazard Cox regression models (including interaction analysis). RESULTS: After a median follow-up of 61.7 months, 5-year event-free survival (EFS) as well as overall survival (OS) rates for the 236 patients were significantly better in the HD arm: EFS: 62% versus 41% [hazard ratio (HR) = 0.60, 95% CI 0.43-0.85, P = 0.004]; OS: 76% versus 61% (HR = 0.58, 95% CI 0.39-0.87, P = 0.007). In multivariate analysis, HD, tumor size <3 cm, positive PR, negative MIB-1 staining, and grade 1/2 were associated with favorable outcome. Interaction analysis showed that regarding predictive effects, triple negative (ER/PR/Her-2/neu) and G3 tumors derived most benefit from HD. CONCLUSION: Tandem HD improves both EFS and OS in HRBC. This therapy effect may be partly attributable to superior efficacy in the subgroup of triple-negative tumors and/or G3 with their poor prognostic marker profile.