Locoregional Failure in Early-Stage Breast Cancer Patients Treated With Breast-Conserving Therapy: Which Patients Benefit From Supraclavicular Nodal Irradiation?

Abstract

To assess the locoregional failure in patients with Stage I-II breast cancer treated with breast conserving surgery followed by adjuvant whole breast radiation therapy (RT), and to evaluate whether potential risk factors might identify patients that are at sufficiently high risk of regional recurrence (RR) to benefit from supraclavicular nodal irradiation. The records of all patients with stage I-II breast cancer treated with breast conserving-surgery and adjuvant whole breast RT were retrospectively reviewed. Loco-regional recurrence (LRR) was defined as clinical or radiographic recurrence in the ipsilateral breast or in the regional lymphatics (axilla, infra/supraclavicular nodes). Kaplan-Meier analysis was used to calculate rates of regional recurrence (RR), LRR, disease-free survival (DFS) and overall survival (OS). Cox proportional hazards methods were used to evaluate potential risk factors. The study was conducted on 492 patients, and the median follow-up was of 95 months (range, 3-309 months). Median patient age was 54 years. One hundred eighty-five (37%) patients were premenopausal; 443 (90%) were affected by invasive ductal carcinoma and 49 (10%) by invasive lobular carcinoma. Four hundred six (83%) women were T1, and 86 (17%) were T2; 324 (66%) were pN0, 47 (10%) pN1a mic, 113 (23%) pN1a, and 8 (2%) were Nx. Two hundred fifteen (44%) tumors were grade 3; 423 (86%) patients were estrogen receptor positive; lymphovascular invasion (LVI) was present in 158 (32%) cases; positive pathologic margin was present in 12 2%) cases. Two hundred twenty-two (45%) patients underwent sentinel node biopsy. One hundred ninety-eight (40%) patients received adjuvant chemotherapy, 246 (50%) received hormonal therapy alone, and 48 (10%) received no adjuvant systemic therapy. The actuarial rates of RR at 5 and 10 years were 2.2% and 3.5%, respectively. The actuarial rates of LRR at 5 and 10 years were 5.5% and 18%, respectively. The actuarial rates of DFS and OS at 10 years were 80.5% and 96.3%, respectively. Statistically significant factors associated with increased risk of RR at the univariate analysis were node positive disease (HR = 3.6, p = 0.003) and the presence of LVI (HR = 3.5, p = 0.03). Patients with Stage I and II breast cancer treated with breast conserving surgery followed by whole breast RT are at a low overall risk of regional and locoregional relapse. However, patients with 1-3 positive lymph nodes and with LVI are higher risk of regional recurrence, and supraclavicular nodal irradiation should be considered.