ObjectiveThe aim of this study is to investigate the impact of primary tumor location on the prognosis of breast cancer patients undergoing breast-conserving surgery. MethodsPatient’s data were retrospectively collected from medical records of individuals who underwent breast-conserving surgery at the Affiliated Hospital of Southwest Medical University between January 2018 and December 2019. ResultsA total of 148 patients were included in this study. The distribution of tumors by location was as follows: the upper outer quadrant accounted for 52.0% (77/148), the lower outer quadrant for 14.2% (21/148), the upper inner quadrant for 14.9% (22/148), the lower inner quadrant for 12.2% (18/148), and the central region for 6.7% (10/148). No statistically significant differences were observed in the comparison of clinicopathological characteristics among breast cancer patients with tumors at different locations (P>0.05). Univariate survival analysis revealed significant correlations between patient prognosis and tumor location, size, molecular classification, WHO grading, as well as endocrine and radiotherapy treatments (P<0.05). Multivariate Cox proportional hazards regression analysis was conducted, and the results demonstrated that the location of the primary tumor serves as a prognostic factor for recurrence, metastasis, and death subsequent to breast-conserving surgery. Notably, in comparison with patients having tumors located in the upper outer quadrant, those with tumors positioned in the upper inner quadrant ［disease-free survival (DFS): HR=3.810, 95%CI (1.101, 13.192), P=0.035; overall survival (OS): HR=10.466, 95%CI (1.775, 61.723), P=0.009］ as well as those with tumors in the lower inner quadrant ［DFS: HR=4.296, 95%CI (1.423, 17.055), P=0.012; OS: HR=17.867, 95%CI (1.832, 174.224), P=0.013］ manifested higher risks of recurrence, metastasis, and death. ConclusionsThis study suggests that the location of the primary tumor in the inner quadrants is associated with an increased risk of recurrence, metastasis, and death in breast cancer patients following breast-conserving surgery. It is recommended that attention should be paid to this aspect in clinical decision-making.