Impact of clinical and pathological factors on local recurrence after breast-conserving treatment: CT-based localization for a tumor bed boost yielded better local control when compared with a surgical scar

Background: We investigated the effects of risk factors on the incidence of local recurrence (LR) in patients who underwent breast-conserving treatment (BCT) for primary breast cancer at a single institution in China from 1999 to 2011. Methods: Patient outcomes were compared with respect to LR, ipsilateral breast tumor recurrence (IBTR), distant disease-free survival (DDFS), and disease-free survival (DFS). Additionally, the risk factors for relapse after BCT were studied. Results: The 2028 patients with invasive breast cancer included in this study were followed for a median of 95 months, during which the 8-year LR, IBTR, DDFS, and DFS rates were 2.6%, 3.0%, 93.7%, and 91.3%, respectively. Lymph node involvement, the human epidermal growth factor receptor 2 (HER2) status, and the use of computed tomography (CT) information during boost field planning were identified as significant predictors of LR and IBTR. Notably, use of the surgical scar for tumor bed identification during boost field planning was associated with a higher adjusted risk of LR, compared with the use of CT. By contrast, the neoadjuvant chemotherapy (NAC) was not an independent predictor of LR (hazard ratio of no NAC vs. NAC, 0.63; 95% confidence interval, 0.33-1.19; P = 0.157). In a multivariate analysis, the age at diagnosis, tumor diameter, lymph node involvement, HER2-positive status, and use of CT information during boost field planning were identified as significant factors affecting DFS. Conclusions: The use of CT information during boost field planning could reduce the risk of LR among patients undergoing BCT. Neoadjuvant and adjuvant treatments for breast cancer did not show the significant difference in respect to the outcome of LR.