St Gallen 2013: News and Progress
The 13th International Breast Cancer Conference held in St Gallen in March 2013 involved some 3700 participants from 95 countries and heard presentations from a faculty widely representative of disciplines and geographical areas. An Expert Panel, which included 51 members from 21 countries, chaired by Aron Goldhirsch and Eric P. Winer met at the conclusion of the conference to review the new information presented and consider treatment recommendations for broad application over the next 2 years. As in the past, this conference included an explicit approach to management of conflicts of interest (see Appendix 2).
Table 1 summarizes the information presented during the conference.
Recent research in local therapy supports the continued trend towards less extensive procedures. Thus, axillary dissection can safely be omitted for patients with micrometastatic disease in sentinel nodes and for those undergoing breast-conserving surgery and whole breast radiation therapy with up to two macroscopically positive sentinel nodes ( Table 1 ).
Two large studies[68,69] support the safety and efficacy of shorter courses of whole breast radiation therapy (40 Gy in 15 or 42.5 Gy in 16 fractions), which offer advantages of convenience and cost over the previous standard of 50 Gy in 25 fractions.
New information became available for several aspects of systemic adjuvant therapy. The ATLAS trial reported superiority for 10 years compared with 5 years of adjuvant tamoxifen. Further follow-up of the extended adjuvant study (MA.17) suggested particular benefit of letrozole for patients who were premenopausal at diagnosis but became postmenopausal by the time of letrozole administration.
The optimal duration of trastuzumab therapy in HER2-positive disease was clarified by results from two trials. The HERA trial showed no additional benefit of 2 years trastuzumab compared with 1 year, while the PHARE trial failed to show non-inferiority of 6 months trastuzumab compared with 1 year. Thus, the de facto standard of care remains 1 year of trastuzumab in patients with HER2-positive disease.
The Early Breast Cancer Trialists' Collaborative Group (EBCTCG) meta-analysis of trials of chemotherapy versus no chemotherapy failed to define any group for which chemotherapy did not offer an advantage. This conclusion is at odds with the results of individual trials and prospective/retrospective analyses of trials with assays such as the 21-gene recurrence score (RS). Furthermore, the control groups of trials included in the EBCTCG overview appear to exhibit much higher degrees of risk than that of patients with luminal disease seen in today's practice who receive modern endocrine therapy as the backbone for their treatment. The EBCTCG report noted that 'information was lacking about tumour gene-expression markers or quantitative immunohistochemistry that might help to predict risk, chemosensitivity, or both'. Subsequent editorial comments[93,94] drew differing interpretations of the EBCTCG conclusions.
Ann Oncol. 2013;24(9):2206-2223. © 2013 Oxford University Press
Copyright European Society for Medical Oncology. Published by Oxford University Press. All rights reserved.