Abstract PS2-03-27: Comparison of Robot-assisted and Conventional Partial Mastectomy in Breast Cancer Patients: A Pilot Study

Abstract Background: Robotic-assisted breast surgery has emerged as a minimally invasive option to achieve oncologic safety and favorable cosmetic outcomes. While robotic-assisted nipple-sparing mastectomy has been studied, data on robotic-assisted partial mastectomy (RAPM) remain limited. This pilot study aimed to compare surgical and patient-reported outcomes between RAPM and conventional partial mastectomy (CPM) in patients with early-stage breast cancer. Methods: This was a non-randomized, prospective comparative pilot study conducted at Severance Hospital between March and July 2024. Ten patients were enrolled, with five undergoing RAPM and five undergoing CPM. Clinicopathologic characteristics, operative outcomes, complication rates, costs, and patient-reported outcomes were analyzed. Fisher’s exact test and the Mann-Whitney test were used to compare categorical and continuous variables, respectively. Results: There were no significant differences in age (median 54.0 vs 48.0 years, p = 0.095), BMI (24.9 vs 21.7, p = 0.095), menopausal status, hormone receptor status, HER2 expression, Ki-67 index, histologic grade, or TNM stage between groups (all p>0.05). The incision size was significantly smaller in the RAPM group (2.74cm vs. 5.20cm, p=0.008). Operative time, blood loss, drain output, and postoperative complications were similar. One patient in the RAPM group experienced a hematoma and wound dehiscence. Surgical cost was approximately 5,000 USD higher in the RAPM group, but the difference was not statistically significant (p=0.140). Patient satisfaction and health-related quality of life (HRQoL) were assessed using the BREAST-Q and EQ5D_5L. Postoperative satisfaction improved in both groups. BREAST-Q scores were slightly higher in the CPM group (100.2 vs. 95.2, p = 0.690), while EQ5D_5L index scores were slightly higher in the RAPM group (0.8498 vs. 0.8276, p = 1.000). No statistically significant differences were observed. Conclusion: RAPM was shown to be a feasible and safe alternative to CPM for early-stage breast cancer patients. While both techniques yielded comparable clinical and patient-reported outcomes, RAPM demonstrated a significant cosmetic advantage due to a smaller incision size. These findings support further evaluation of RAPM in larger, long-term studies. Citation Format: S. Lee, J. Ahn, S. Lim, H. Alanazi, H. Park. Comparison of Robot-assisted and Conventional Partial Mastectomy in Breast Cancer Patients: A Pilot Study [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS2-03-27.