Factors associate with borderline or invaded margins in breast cancer surgery at the Val d’Aurelle Montpellier CRLC Véronique Mboua Batoum*, Esther Dina Bell, Christianne Nsahlai, Junie Annick Metogo Ntsama, Esther Juliette Meka, Marian Gutowski, Simon Thezenas, William Jacot *Corresponding autor : vbatoum@gmail.com Introduction: The inadequate status of the resection margins after breast cancer surgery is an important predictor of local tumor recurrence. The objective of our study was to determine the factors associated with positive or invaded resection margins. Methodology: Our retrospective study included a cohort of 652 patients with early invasive breast cancer who underwent breast cancer conserving surgery at the Val d’Aurelle Regional Cancer Center. We defined positive margins as those with a distance of less than or equal to 2 mm from the tumour. The data were analysed using STATA® 10.0 software. Results: In our study, The median distance from the tumour to the surgical resection site was 5mm [0.0 - 35.0mm]. Resection margins were positive in 208 patients (31.9%). The rate of positive resection margins was significantly higher in non-menopausal patientss (P =0,0050), in those with tumours less than 2 cm in size (P = 0,0004), with ductal carcinoma in situ (DCIS) component and without lymph node involvement (P =0,0082). Re-excision surgery was performed in 229 patients (35.1%). Conclusion: Consideration of each of these factors associated with positive resection margins shoud help the surgeons to perform a wider excision, in other to obtain clear resection margin during the initial breast cancer surgery. Key words: breast cancer, conservative surgery, resection margins, risk factors for positive margins Citation Format: veronique M. Mboua Batoum, esther D. Dina Bell. Factors associate with borderline or invaded margins in breast cancer surgery at the Val d’Aurelle Montpellier CRLC [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-09-10.