Irradiation after Surgery for Breast Cancer Patients with Primary Tumours and One to Three Positive Axillary Lymph Nodes: Yes or No?

Objective and Methods: We retrospectively analyzed clinicopathologic features and survival in breast cancer patients who had T1 or T2 primary tumours and 1–3 histologically involved axillary lymph nodes and who were treated with modified radical mastectomy without adjuvant radiotherapy (RT). We also explored prognosis to find the high- and low-risk groups. Results: From May 2001 to April 2005, 368 patients treated at Tianjin Tumor Hospital met the study criteria. The 5- and 8-year rates were 7.2% and 10.7% for locoregional recurrence (LRR), 85.1% and 77.7% for disease-free survival (DFS), and 92.8% and 89.3% for overall survival (OS). Multivariate Cox regression analysis showed that age, tumour size, estrogen receptor (ER) status, and lymphovascular invasion (LVI) were independent prognostic factors for LRR and DFS. Based on 4 patient-related factors that indicate poor prognosis (age < 40 years, tumour > 3 cm, ER negativity, and LVI), the high-risk group (patients with 3 or 4 factors, accounting for 12.5% of the cohort) had 5- and 8-year rates of 24.3% and 36.9% for LRR, 57.2% and 39.2% for DFS, and 74.8% and 43.8% for OS compared with 5.0% and 7.1% for LRR, 88.9% and 83.1% for DFS, 91.6% and 83.4% for OS in the low-risk group (patients with 0–2 factors, accounting for 87.5% of the cohort; p < 0.001). Conclusions: Our study identified several risk factors that correlated independently with a greater incidence of LRR and distant metastasis in patients with T1 and T2 breast cancer and 1–3 positive nodes. Patients with 0–2 risk factors may not be likely to benefit from post-mastectomy RT, but patients with 3–4 risk factors may need RT to optimize locoregional control and improve survival.