Neoadjuvant clinical trials for the treatment of primary breast cancer: the experience of the German study groups.

The advantages of neoadjuvant chemotherapy are the ability to 1) increase the rate of breast conservation and improve operability, 2) to reduce mortality by recognizing resistance mechanisms early, and 3) to investigate the activity of new agents by assessing the pathological complete response rate as a surrogate marker for clinical efficacy. The German Breast Group (GBG) is a cooperative study group which focuses on neoadjuvant therapy for breast cancer. This group cooperates closely with the German Gynecological Oncology Working Group-Breast (AGO-B). Additionally, these two German study groups maintain close ties with other national and international study groups, such as the Breast International Group (BIG), Austrian Breast and Colorectal Cancer Study Group (ABCSG), Central European Cooperative Oncology Group (CECOG), International Cooperative Cancer Group (ICCG) and National Surgical Adjuvant Breast Project (NSABP). A series of clinical trials evaluating the role of neoadjuvant therapy in women with primary breast cancer have been designed, performed and published over the last 10 years. This article summarizes the results of the neoadjuvant trials that have been conducted by the German study groups, outlines ongoing clinical research projects, and discusses concepts for future clinical trials.