Abstract Background:Globally, triple-negative breast cancer (TNBC) is responsible for approximately 15% of all invasive Breast cancer and has been typically associated with poor prognosis. Some retrospective studies have suggested a relatively higher incidence of TNBC in the Middle East and North African Arab countries. Nevertheless, there is complete lack of prospective data, on TNBC in the region, including clinico-pathologic characteristics, treatment patterns and disease outcomes. The TRIPOLI study aims to bridge this information gap.Methods:TRIPOLI is an ongoing prospective multinational, disease registry, designed to recruit 700 newly diagnosed TNBC patients, from 15 institutions within 9 Arab countries: Egypt, Jordon, Morocco, Kingdom of Saudi Arabia, Lebanon, Oman, Kuwait, Qatar and Iraq. This interim analysis includes the patients’ characteristics and treatment approaches of the first 449 cases included in the study from December 2017 to September 2019.Results:All the 449 TNBC patients were females, with a median age of 49 years (range 23.8 - 93.6 years). Premenopausal status was reported in 54.7%, while a positive family history of BC was stated in 25.2% of these cases. 0.2% of patients were below normal (BMI<18.5), 17.2% had normal weight (18.5≤BMI<25), and 30.5% were overweight (25≤BMI<30). Obesity (BMI ≥ 30) was present in 52% of these patients, while a parity of ≥3 children was present in 254 patients (59.8%) Sixty-six patients (14.7%) had tumours smaller than 2cm. 159 patients (35.4%) had node negative disease. The majority of patients had invasive duct carcinoma (87.1%) with 5 patients (1.1%) grade I, 181 (40.3%) grade II and 234 (52.1%) grade III tumours (29 (6.5%) had unknown histological grade). Thirty-four patients (7.6%) presented with stage I disease, 203 patients (45.2%) with stage II, 161 patients (35.9%) with stage III and 50 patients (11.1%) presented with stage IV disease.Out of the 387 patients with non-metastatic disease who started treatment, 217 patients (56.1%) had upfront surgery and 170 patients (43.9%) started with neoadjuvant chemotherapy. Compared to patients > 40 years, patients ≤ 40 years were less likely to be obese (39.4% versus 60.6%; p=0.002), more likely to have grade III tumours (62.3% versus 53.5%; p=0.116), more likely to have T3 or T4 tumours (41.4% versus 32.7%; p=0.038).Conclusion:In this interim analysis, Arab women with TNBC had high parity (≥ 3) and high BMI, compared to existing literature based on western population. High tumor grade, younger age and advanced stages at presentation are in line with similar world-wide reports. Younger women in the Arab region (≤40 years) presented with poor prognostic features, which will be further elucidated in subsequent reports. Citation Format: Hamdy A. Azim, Alaa Kandil, Heba El Zawahry, Hikmat Abdel-Razeq, Hesham Elghazaly, Suad Al Kharusi, Manal M. Abdelwahab, Salah Fayaz, Ahmed Saadeddin, Huda A. Alabdulkarim, Rasha Aboelhassan, Hassan Errihani, Tahseen Al Rubai, Salha Bujassoum Al Bader, Nashwa Mohamed Abdel Aziz, Nagi El Saghir, Giulia Attinà, Ahmed Yosry, Mohamed El Leithy, Loay Kassem, Marwan Ghosn. Triple negative breast cancer prospective registry in middle East and Africa (TRIPOLI) study: Interim analysis of the patients’ characteristics [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-65.