Prognostic Factors in Patients with Triple Negative Breast Cancer Undergoing Adjuvant Radiotherapy: A ۱۰-Year Single Center Experience

Breast cancer (BC) is the most common type of cancer in women in the world, and it is the ۲nd most common cause of cancer-related deaths.۱ Breast cancer is a heterogeneous disease and is divided into ۴ molecular groups: Luminal A, Luminal B, human epidermal growth factor receptor-۲ (HER-۲) positive and triple negative subtypes according to hormone receptor status.۲ Triple negative breast cancer (TNBC) consists of subgroups in which estrogen receptor (ER) and progesterone receptor (PR) stain less than <۱% and HER-۲ is negative.۳ TNBC accounts for approximately ۱۰-۱۵% of all breast cancers.۴,۵ The risk of TNBC increases with young menarche, young first birth, non-breastfeeding, and abdominal obesity.۶ It is more common in young women, obese people and BRCA-۱ carriers.۷ TNBC is a heterogeneous group and has at least six different genetic subtypes.۸ It has a histopatho-logically high grade, increased mitotic activity, a high nuclear cytoplasmic ratio and an accelerated tumor proliferation rate.۶ We observe a larger tumor size۱, less nodal involvement,۷ more distant metastasis,۶ poor prognosis,۹ and increased mortality,۴ in this group of patients. It was observed that distant metastases are more common three years after the diagnosis,۱۰ and lung and that brain metastases are more common than bone metastases.۱۱,۶ Mortality rates in the first ۵ years after diagnosis are ۴۰%.۱۰ Their ۵-year survival rate is less than the subtype with the best prognosis at ۸-۱۶%.۶