Competing interests

All authors have completed and submitted the Declaration of Interest form. Kerstin Wimmer reports a relationship with Roche and Pfizer Inc that includes travel reimbursement. Marija Balic reporting having received research funding from Amgen, Celgene, Eli Lilly, Novartis, Roche, Pfizer and Samsung, having an advisory role at Amgen, AstraZeneca, Celgene, Daiichi Sankyo, Eli Lilly, MSD, Novartis, Pierre Fabre, Pfizer, Roche, Samsung, Gilead and being part of the speakers bureau for Amgen, AstraZeneca, Celgene, Daiichi Sankyo, Eli Lilly, MSD, Novartis, Pierre Fabre, Pfizer, Roche, Seagen, Gilead. Georg Pfeiler has received grants and honoraria from Pfizer, Roche, Seagen, Daiichi, Lilly, Novartis, AstraZeneca, MSD and UCB. Richard Greil reports honoraria from Celgene, Roche, Merck, Takeda, AstraZeneca, Novartis, Amgen, BMS, MSD, Sandoz, Abbvie, Gilead, Daiichi Sankyo and Sanofi a consulting or advisory role at Celgene, Novartis, Roche, BMS, Takeda, Abbvie, Astra Zeneca, Janssen, MSD, Merck, Gilead, Daiichi Sankyo and Sanofi. Moreover, Richard Greil reports having received research funding from Celgene, Roche, Merck, Takeda, AstraZeneca, Novartis, Amgen, BMS, MSD, Sandoz, Abbvie, Gilead and Daiichi Sankyo and travel support (accommodations, expenses) from Roche, Amgen, Janssen, Astra Zeneca, Novartis, MSD, Celgene, Gilead, BMS, Abbvie and Daiichi Sankyo. Christian F Singer reports that administrative support, statistical analysis, and writing assistance were provided by Medical University of Vienna. Moreover, Christian F Singer reports a relationship with Medical University of Vienna that includes board membership, consulting or advisory, funding grants, speaking and lecture fees, and travel reimbursement. Simon P Gampenrieder reports a relationship with Novartis Pharma AG and Pfizer Inc that includes speaking and lecture fees and travel reimbursement, a relationship with Roche that includes consulting or advisory, funding grants, speaking and lecture fees, and travel reimbursement, a relationship with Bristol Myers Squibb Co, AstraZeneca Pharmaceuticals LP, Merck Sharp & Dohme UK Ltd, Eli Lilly and Company, Seagen that includes consulting or advisory and speaking and lecture fees. Moreover, Simon Gampenrieder reports a relationship with Amgen Inc, Shire, Bayer AG, Celgene GmbH and Daiichi Sankyo that includes travel reimbursement. Martin Filipits has received honoraria from Astra Zeneca, Biomedica, Biorad, Boehringer Ingelheim, Eli Lilly, Merck, Novartis, and Pfizer. Michael Gnant reports personal fees / travel support from Amgen, DaiichiSankyo, AstraZeneca, EliLilly, LifeBrain, Nanostring, Novartis, PierreFabre, MSD; an immediate family member is employed by Sandoz. Florian F Fitzal reports a role as Editor for Oncoplastic Surgery part I and II: Springer, having received travel and scientific support from Comesa (Mentor), Novartis, Roche, Astra Zeneca, Pfizer, Myriad, Nanostring, Bondimed (Polytech, Integra) and Lilly, having an advisory role for Pfizer, Astra Zeneca, Lilly and Roche and being founder of the Breast analyzing tool (BAT): breastanalyzing.com. Following authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper: Dominik Hlauschek, Christian Fesl, Lidija Sölkner, Ruth Helfgott, Raimund Jakesz, Günther Steger, Christoph Suppan.

Ethical approval and consent to participate

The two randomized, prospective ABCSG-06 (NCT00309491) and ABCSG-06a (NCT00300508) trial were conducted by the Austrian Breast Cancer and Colorectal Study Group (ABCSG) and were registered clinical trials. The respective studies have been approved by the responsible ethics committees for each participating site (e.g. EC Med.Univ. Vienna from 10Apr1990 (ABCSG-6) and from 04Dec1995 (ABCSG-6a/ 1033AU/0001)). The trials were conducted according to the guidelines of the Declaration of Helsinki and were carried out in accordance with the guidelines for Good Clinical Practice. All patients provided signed informed consent.