Effect of modified radical mastectomy versus breast-conserving surgery on quality of life and psychological outcomes among women with breast cancer: A longitudinal observational study

Background: Breast cancer is the most common malignancy among women. Breast-conserving surgery (BCS) and modified radical mastectomy (MRM) are standard surgical treatments; yet, their comparative effects on quality-of-life (QoL) and psychological outcomes remain insufficiently understood. Evidence regarding variation in these outcomes across molecular subtypes of breast cancer is scarce. Aim: To compare the impact of BCS and MRM on QoL, psychological outcomes, and suicidal ideation at six weeks, and to examine differences across molecular subtypes of breast cancer. Materials and Methods: This prospective observational study included 52 breast cancer patients, undergoing BCS ( n = 26) and MRM ( n = 26). QoL was assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core-30 and Breast Cancer-Specific Module-23. Psychological outcomes were measured using the Depression, Anxiety, and Stress Scale-21, and suicidal ideation using the Columbia Suicide Severity Rating Scale. Changes from baseline to six weeks between surgical groups were analyzed using a difference-in-differences (DiD) approach. Comparisons across molecular subtypes were performed using the Kruskal–Wallis test. Results: Both surgical groups demonstrated significant improvement in overall QoL and psychological outcomes at six weeks. DiD analysis showed greater improvement in cognitive functioning, dyspnea, and anxiety symptoms among patients who underwent MRM. Across molecular subtypes, patients with triple-negative breast cancer reported poorer future perspective and greater distress related to hair loss. Conclusion: Both surgical approaches improved QoL and psychological outcomes, although better benefits after the MRM.