Triple-Negative Breast Cancer in Brazilian Women without Metastasis to Axillary Lymph Nodes: Ten-Year Survival and Prognostic Factors

Aims: To determine the 10-year overall survival (OS) in triple-negative (TN) and non-TN breast cancer (BC) patients, and to identify associated independent prognostic factors.
Study Design: Descriptive and survival.
Place and Duration of Study: Pathology Division at National Cancer Institute, Rio de Janeiro, Brazil, between 1992-1996.
Methodology: Population: 348 women patients with invasive ductal carcinoma without lymph node metastasis. Analyzed variables: age, treatment, surgery type, tumor size, skin involvement, histological grade, vascular invasion, estrogen and progesterone receptors, HER-2, Ki-67 and p53. Statistical analysis performed: Kaplan-Meier survival curves, log rank test, and multivariate Cox models.
Results: 27% of the studied women were categorized as TNBC and 73%, as non-TNBC. The former showed higher frequency of age <50yr, preoperative chemotherapy, tumors >5cm, high grade, vascular invasion, and positive p53, (P=.05). Ten-year OS among TNBC patients was 61.6%, and 70.1% for non-TNBC patients (P=.058). Survival was higher in TNBC patients treated with partial surgeries, tumors ≤5cm, without skin involvement, low grade, and Ki-67 negative (P=.05). Among non-TNBC patients, higher survival was observed in patients without skin involvement, low grade, no vascular invasion, and p53 negative, (P=.05). Cox modelization showed a 2-fold higher death risk for TNBC patients aged ≥50yr, about 2.5-fold higher risk related to preoperative chemotherapy, high grade tumor and skin involvement, and a 3.0-fold higher risk for Ki-67 positive patients (P=.05). For non-TNBC patients, a 2.0-fold increased death risk was verified in patients with skin involvement and vascular invasion (P=.05).
Conclusion: TNBC patients showed a worse prognosis and survival when compared to non-TNBC patients. A worse 10-yr survival among TNBC patients was associated with age ≥50yr, preoperative chemotherapy, skin involvement, high histological grade, and Ki-67 positive tumors. For non-TNBC patients, the worst prognosis was related to skin involvement and vascular invasion. These predictors need to be further validating by other studies.