The Role of the Neo-Bioscore Staging System in Guiding the Optimal Strategies for Regional Nodal Irradiation Following Neoadjuvant Treatment in Breast Cancer Patients with cN1 and ypN0–1

Abstract

Background

The role of regional nodal irradiation (RNI) in patients with cN1 breast cancer following neoadjuvant treatment (NAT) is still controversial. The Neo-Bioscore staging system has shown promising prospect in assessing individual prognosis after NAT, and we sought to evaluate the role of Neo-Bioscore in guiding RNI following NAT.

Methods

Medical records of 163 women with cN1 and ypN0–1 disease treated with NAT between 2009 and 2014 were retrospectively reviewed and a Neo-Bioscore was assigned to each patient. Survivals were calculated using the Kaplan–Meier method and compared with the log-rank test. Multivariate analysis was used to identify independent predictors by using Cox proportional hazards models.

Results

The median follow-up after surgery was 59.4 months. Of all 163 patients, 119 received RNI. At surgery, 36 patients (22.1%) had pathological complete response (pCR), while 89 patients (54.6%) achieved ypN0. In the whole cohort, RNI significantly improved distant metastasis-free survival (DMFS) on multivariable analysis. In the subgroup of patients with a Neo-Bioscore of 1–3, RNI significantly improved the 5-year DMFS rate of 97.0% versus 76.9% (p = 0.002), 5-year regional node recurrence-free survival rate of 95.5% versus 76.9% (p = 0.007), and 5-year overall survival rate of 100% versus 89.2% (p = 0.005). No significant difference in outcomes was found between the RNI and non-RNI groups in patients with a score of 4–6.

Conclusions

In patients with cN1 and ypN0–1, RNI was found to significantly improve DMFS following NAT. Patients with a Neo-Bioscore of 1–3 are more likely to benefit from RNI, however a large prospective study is needed to confirm this finding.

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