OF THE QUALITY OF LIFE AFTER RADICAL SURGERY (MASTECTOMY) IN RELATION TO BREAST CONSERVING SURGERY (QUADRANTECTOMY) Objectives: The aim of this study was to determine the differences in the quality of life among patients who have undergone radical surgery (mastectomy) and breast-conserving surgery (quadrantectomy). Also, to determine the differences in the quality of life between those two groups at the first appearance of the disease in relation to the recurrence of the disease, and to determine the differences in relation to age. Methods and participants: 130 patients were included in this study; 65 patients who underwent radical surgery (mastectomy) and 65 patients who underwent breast-conserving surgery (quadrantectomy). The quality of life was assessed using the self-administered EORTC core questionnaire QLQ-C30 and breast cancer-specific module QLQ-BR23. Results: On most functional and symptom scales, the patients who underwent quadrantectomy reported better quality of life compared to mastectomy patients. At the first appearance of the disease, the quadrantectomy patients reported better results; however, at the recurrence of the disease, the mastectomy patients reported better outcomes. Patients, aging from 17-35 and 56 and more who underwent quadrantectomy reported better results, however mastectomy patients aging from 36-55 reported better results. Conclusion: The patients who underwent quadrantectomy reported better quality of life than patients who underwent mastectomy. The quality of life at the first appearance of the disease was better with quadrantectomy patients, while at the recurrence of the disease the quality of life was better with mastectomy patients. The differences in the quality of life between quandrantectomy and mastectomy patients were most significant in groups of patients aging from 17-35 years.