[Prognosis and risk factors of 1 791 patients with breast cancer treated with breast-conserving surgery based on...

Objective: To investigate the overall efficacy of early breast cancer after breast-conserving treatment. To analyze risk factors affecting local regional recurrence (LRR), distant metastasis (DM) and survival. Methods: 1 791 breast cancer patients treated with breast-conserving surgery were retrospectively analyzed. The inclusion criteria were pathologic diagnosis of invasive breast cancer without supraclavicular and internal mammary node metastasis, T1-2N0-3M0, and no neoadjuvant therapy. Univariate analysis of survival was performed by Kaplan-Meier method and log rank test. Cox regression model was used for multivariate analysis. Results: The median follow-up time was 4.2 years. For all patients, the 5-year LRR, DM, disease-free survival(DFS) and overall survival(OS) rates were 3.6%, 4.6%, 93.0% and 97.4%, respectively. The LRR rates of patients with Luminal A, Luminal B1, Luminal B2, HER-2 over-expressed and triple-negative breast cancer were 2.0%, 6.1%, 5.9%, 0 and 10.0%, while the DM rates were 3.2%, 6.7%, 8.3%, 4.8% and 7.3%, respectively. Among the N0 patients, axillary dissection was performed in 689 cases and sentinel lymph node biopsy in 652 cases. The 5-year LRR rates were 3.3% and 3.2% (P=0.859), and the OS rates were 98.2% and 98.3% (P=0.311) respectively, which showed no statistically significant. There were 1 576 patients that underwent postoperative radiotherapy. Postoperative radiotherapy significantly reduced the 5-year LRR compared with surgery alone (2.5% vs 12.9%). The 5-year LRR rates of patients who received conventional fractionated radiotherapy and hypo-fractionated radiotherapy were 2.7% and 3.1%, respectively. But the difference was not statistically significant (P=0.870). Multivariate analysis showed that age, lymphovascular invasion, pathological T staging, postoperative radiotherapy, ER/PR status and endocrine therapy were independent factors of LRR in breast cancer patients (all P<0.05). Histological grade and pathological N staging were independent factors of DM (all P<0.05). The age, lymphovascular invasion, pathological T and N staging, postoperative radiotherapy, ER/PR status and endocrine therapy were independent factors for DFS (all P<0.05). Histological grade, pathological N staging, ER/PR status and endocrine therapy were factors for OS (all P<0.05). Conclusions: With contemporary standard treatment, the recurrence rate of early breast cancer after breast conserving treatment is less than 10%. Node-negative patients after sentinel lymph node biopsy did not need axillary dissection. The overall utilization of radiotherapy after breast conserving surgery is satisfactory. Hypofractionated radiotherapy is as effective as conventional fractionated radiotherapy. Local regional recurrence and distant metastasis have different risk factors.