Abstract PO4-23-07: Impact of distance between tumor and nipple on locoregional recurrence in breast cancer

Introduction: Mastectomy is usually recommended for centrally located tumors due to the risk of nipple invasion. While it is well known that there is no significant difference in survival outcomes according to tumor location, central tumors have a higher likelihood of main lactiferous duct invasion, which can result in the migration of tumor cells to the periphery. Therefore, we conducted an investigation specifically focusing on locoregional recurrence (LRR) rates based on the tumor-to-nipple distance (TND). Method: We retrospectively collected the data of patients who underwent breast cancer surgery between 2004-2018 from two institutions. Patients who underwent neoadjuvant chemotherapy were excluded. TND information was obtained from preoperative MRI records. Results: A total of 9,014 patients were included in the study, and the median tumor-to-nipple distance (TND) was 3.4 (0.0-15.0) cm. For all patients, the restricted cubic spline curve analysis showed that the hazard risk of LRR increased with shorter TND. The pattern was more pronounced in the breast-conserving surgery (BCS) group, whereas the mastectomy group showed a relatively constant risk regardless of TND. Thus, we conducted survival analysis for 5,455 patients who underwent BCS. We set the cutoff for TND as 2.5cm as it showed the lowest p-value for LRR rate. Compared to those with TND >2.5cm, patients with TND≤2.5cm showed significantly lower LRR (HR,1.83;95%CI,[1.37-2.46],p< 0.001) and distant metastasis(DM) (HR,1.53;95%CI,[1.16-2.02],p=0.002) rates. Overall survival was not different between two groups (p=0.405). Cox-regression analysis revealed that TND still impacts LRR (HR,1.52;95%CI,[1.11-2.09],p=0.010) but not DM. Importantly, TND still remained significant factor affecting LRR when analyzed as continuous variable (HR,1.04; 95%CI,[1.02-1.06],p< 0.001). The prognostic impact of TND was particularly evident in patients with high mammographic density. Discussion: BCS can be performed for centrally located tumors, as it offers considerable oncologic safety compared to mastectomy. However, for patients who have a fear of recurrence and are reluctant to undergo re-operation, mastectomy would be a good choice. Citation Format: Jong-Ho Cheun, Eunhye Kang, Hong-Kyu Kim, Han-Byoel Lee, Hyeong-Gon Moon, Wonshik Han, Ki-Tae Hwang. Impact of distance between tumor and nipple on locoregional recurrence in breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-23-07.