Characteristics of Screen-Detected Breast Cancer of Turkish Bahcesehir (Istanbul) Screening Project

PurposeThe Turkish Bahcesehir Breast Cancer Screening Project is a 10-year organized population-based screening program carried out in one of the largest counties of Istanbul, Turkey. The aim of the current study was to examine the biologic features of screen-detected and interval breast cancers for the first 9-year study period.MethodsBetween January 2009 and January 2018, 26,040 mammographies were performed with 2-year intervals for 8,408 women age 40 to 69 years. Clinicopathologic and biologic tumor characteristics—estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2-neu, and protein encoded by the MKI67 gene (Ki-67) —were analyzed for those patients who were diagnosed with breast cancer. Interval cancer was defined as symptomatic cancer diagnosed within 24 months of a negative screening. Ki-67 level > 20% was considered a high score.ResultsMedian age was 52.5 years, and 37% were younger than age 50 years. Of 8,408 women, 113 breast cancers (1.3%) were detected. There were...