Palliative systemic therapy and overall survival of 1,395 patients with advanced breast cancer - Results from the prospective German TMK cohort study.

Data on treatment and outcome of advanced breast cancer in routine practice are rare, especially concerning recurrent disease, but important to complement the results from clinical trials and to improve the standard of care. We present data on choice of systemic first-line treatment, number of treatment lines, and survival of patients treated by medical oncologists in Germany. 1395 patients recruited by 124 sites at start of first-line therapy into the ongoing, prospective German clinical cohort study TMK (Tumour Registry Breast Cancer) between February 2007 and October 2015 were analysed. The median OS was 33.8 months (95% CI 30.2-40.2) for HR-positive/HER2-negative, 38.2 months (95% CI 31.3-43.0) for HER2-positive and 16.8 months (95% CI 11.5-22.0) for triple negative breast cancer. Patients with triple negative tumours more often died before start of a third-line therapy than patients with HR-positive or HER2-positive tumours (44% vs. 25%). Use of taxane-based chemotherapies has increased since 2007, with 65% of all first-line chemotherapy-treatments containing taxanes in 2013-15 (60% HR-positive/HER2-negative, 75% HER2-positive, 56% triple negative). 52% of the patients with HR-positive/HER2-negative tumours received first-line endocrine therapy in 2013-15; when restricted to patients with only non-visceral metastases this percentage increased to 63%. To our knowledge, this is the first cohort study showing systemic first-line therapy for all subtypes of advanced breast cancer. Overall survival in the TMK is comparable to that reported by clinical trials despite the inclusion of older and comorbid patients.