Triple-Negative Breast Cancer: Clinical Characteristics, Prognostic Features, and Long-Term Outcome: A Comparative Study

Abstract

Background: Because of the reported poor prognosis and absence of effective and specific therapeutic approaches, triple-negative breast cancer (TNBC) tumors have remained as an important area of investigations for clinicians and researchers. The aim of this study was to determine the clinical, pathological, histological, prognostic features, and outcome associated with this type of breast cancer in Iran. We also tried to identify main determinants of long-term survival in women suffered from TNBC tumor type.
Methods: This is a historical cohort study of 546 consecutive female breast cancer patients with known status of hormonal receptors and diagnosed at the Rasoul-e-Akram University Hospital of Iran between January 2009 and June 2011. Baseline data were collected from patient records and hospital charts. Long-term outcome was determined from clinic records when available or by means of written correspondence with patients' physicians and telephone interviews directly with the patients or with family members. Follow-up data were collected by our research personnel for a mean follow-up duration 5.7 years.
Results: A total of 86 of 546 final included participants with breast cancer were identified as having TNBC (15.8%).The patients with TNBC diagnosis were significantly younger than non-TNBC group and family history of breast cancer was more prevalent in former group. Regarding histopathological feature, medullary feature was more prevalent in TNBC group, while other features were similarly revealed in both groups. With respect to tumor grading, TNBC group was graded higher than non-TNBC group that grade III of tumor was reported in 51.1% of the TNBC patients, but in 15.9% of another group. Also, the stage of tumor was significantly higher in the TNBC group. Tumor size > 50 mm was observed in 18.6% of the TNBC and 14.8% of non-TNBC groups. Metastasis to liver as well as concurrent metastasis to brain and pulmonary was more prevalent in TNBC compared with another group. The Kaplan-Meier curves based showed the survi al probability at 1-year, 3-year, and 5-year of follow-up in TNBC group was 92.7%, 86.2%, and 44.9%, respectively. This survival rates in non-TNBC group was 98.7%, 87/2%, and 72.5%, respectively. Multivariable logistic regression analysis showed that TNBC diagnosis could strongly predict long-term mortality in breast cancer patients. Besides, tumor size, number of involved lymph nodes and higher tumor grade were other determinants of cancer-related long-term mortality.
Conclusion: The present study on Iranian TNBCs population shows that TNBCs account for about 15.8% of all invasive breast cancers, and they usually have a high histological stating and metastasis susceptibility.