Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 14 2 2023 06 26 87 94 Kamran Roudini Cancer Institute, Imam Khomeini Hospital Complex, Tehran university of Medical Sciences, Tehran, Iran Mehrzad Mirzania Imam Khomeini Hospital Complex, Tehran university of Medical Sciences, Iran, Islamic Republic Of Seyyed Amirhossein Emami Imam Khomeini Hospital Complex, Tehran university of Medical Sciences, Iran, Islamic Republic Of Seyyed Reza Safayi Imam Khomeini Hospital Complex, Tehran university of Medical Sciences, Iran, Islamic Republic Of Ehsan Kamali yazdi Hematology and Oncology Department, Imam Khomeini Hospital Complex, Tehran University of Medical Science, Tehran, Iran Nasim Zarifi Tehran University of Medical Science, Iran, Islamic Republic Of Masoud Mortezazadeh Tehran University of Medical Science, Iran, Islamic Republic Of Shima Rafiee Tehran University of Medical Science, Iran, Islamic Republic Of Abbas Mofidi School of Medicine, Iran University of Medical Science, Tehran, Iran Mehdi Kashani School of medicine, Tehran university of medical sciences, Tehran, Iran Ensieh sadat Mansouri Tehran University of Medical Science, Iran, Islamic Republic Of Mohammad Siahkalmahalleh Tehran University of Medical Science, Iran, Islamic Republic Of Ahmad Khajeh Mehrizi Imam Khomeini Hospital Complex, Tehran university of Medical Sciences, Iran, Islamic Republic Of 2023 01 06 2023 04 25 Abstract : Background: This study evaluated the effect of adjuvant chemotherapy and hormone therapy on overall survival and disease-free survival in patients with breast cancer with hormone receptor-positive, HER2-negative tumor without lymph node involvement. Methods: Breast cancer patients with hormone receptor-positive, HER2-negative, and no lymph node involvement were included in this retrospective cohort study. Patient records were used to collect data on sex, age, time of disease onset, tumor subtype, tumor size, grade, lymphovascular and perineural involvement, ki67, and treatment protocols. Patients were divided into 2 groups: Patients who received both adjuvant chemotherapy and hormonal therapy and patients who received hormonal therapy only. Disease-free survival index (DFS) and overall survival index (OS) were evaluated. Results: Sixty-seven female patients were enrolled in this study. Of them, 68.2% received both adjuvant chemotherapy and hormonal therapy and 31.6% received hormonal therapy only. During follow-up, recurrences occurred in 8 patients. The 3-year and 5-year DFS were 93.4% and 90%, respectively. The 3-year and 5-year DFS were 94% and 92%, respectively, in patients who received both adjuvant chemotherapy and hormonal therapy, and 91% and 85%, respectively, in patients who received hormonal therapy. None of the factors studied affected the 3-year and 5-year DFS. The 3-year and 5-year DFS OS were 98.6% and 96.9%, respectively CONCLUSION: Adjuvant chemotherapy in patients with breast cancer with hormone receptor-positive, HER2-negative, and no lymph node involvement compared with similar patients receiving hormone therapy alone had no significant difference in disease-free survival index and overall survival index. Keywords: breast cancer; disease-free survival index; overall survival index https://bccr.tums.ac.ir/index.php/bccrj/article/view/461