Outcome of 561 non-metastatic triple negative breast cancer patients: multi-center experience from Turkey.

Purpose: Triple-negative breast cancers account for 15% of breast carcinomas and, when present as early-stage disease, they are associated with higher rates of recurrence and early distant metastasis risk when compared to hormone receptor positive and human epidermal growth factor receptor (HER-2) positive breast cancers. In this study we aimed to explore the basic clinicopathological characteristics, prognostic factors and recurrence patterns of non-metastatic triple negative breast cancer patients.

Methods: In this study 561 non-metastatic triple-negative breast cancer female patients admitted to 8 different cancer centers in Turkey between 2000 and 2010 were retrospectively evaluated through their medical records, to identify the basic clinico-pathological characteristics, prognostic factors and recurrence patterns.

Results: The ratio of triple-negative breast cancer was 12%. The median age of patients was 48 years, of whom 311 (55.4%) were premenopausal. The majority had early-stage breast cancer at the time of diagnosis (16.8% stage I, 48.1% stage II, 35.1 % stage III) and the most commonly identified variant was invasive ductal carcinoma (84.1%). Grade II and III tumors were 27.1 and 48.5%, respectively. Adjuvant chemotherapy was administered to 90.5% of women and adjuvant radiotherapy to 41.2%. Median patient follow up was 28 months (range 3-290). During the follow up period 134 (23.8%) patients developed metastatic disease. In most of these cases, metastatic sites were bone, soft tissue, and lung. Factors affecting disease free survival (DFS) and overall survival (OS) were age (both p<0.001), lymph node involvement (both p<0.001), lymphovascular invasion (LVI) (p<0.001 and p=0.004, respectively), tumor stage (both p<0.001), adjuvant administration of anthracycline-based chemotherapy (both <0.001) and type of surgery (not significant for DFS but p=0.05 for OS). Three-year DFS and OS were 72.0 and 93.0%, respectively.

Conclusion: Age, lymph node involvement, LVI, stage, and adjuvant chemotherapy were determined as prognostic factors for DFS and OS. The most common recurrence sites were bone, soft tissue and the lung. Further prospective randomised trials are needed to confirm the prognostic and predictive factors identified in this study.