Internal mammary node irradiation improves 8-year survival in breast cancer patients: results from a retrospective cohort study in real-world setting

  • Xuanyi Wang
  • Jurui Luo
  • Kairui Jin
  • Xingxing Chen
  • Li Zhang
  • Jin Meng
  • Xiaomeng Zhang
  • Zhen Zhang
  • Zhimin Shao
  • Jose G. Bazan
  • Xiaomao Guo
  • Zhaozhi YangEmail author
  • Xiaoli YuEmail author
Original Article



Regional nodal irradiation (RNI) improves disease outcome in breast cancer patients, but the contribution of internal mammary node irradiation (IMNI) in the context of modern systemic treatment is still controversial. The aim of our study is to evaluate the effect of IMNI in patients with modern systemic treatment in real-world setting.


We retrospectively analyzed patients with primary breast cancer treated with surgery followed by adjuvant chemotherapy and adjuvant chestwall/breast irradiation and RNI from 5/2007-12/2010. RNI was delivered to the ipsilateral supraclavicular region and infraclavicular region + / − IMNs. We separated two groups based on the presence and the absence of IMNI. The primary end point was disease-free survival (DFS). DFS and overall survival (OS) were evaluated with Kaplan–Meier method. Differences between two groups were compared with the log-rank test (p < 0.05 considered significant). We used two methods to account for potential confounders: propensity score matching (PSM) and Cox regression analysis.


We analyzed 872 patients who received RNI with IMNI (n = 390) or without IMNI (n = 482). Median radiation dose was 50 Gy. Median follow-up was 98 months. IMNI improved 8-year DFS rates versus no IMNI: 75.9% and 64.9% (p < 0.001). After PSM, baseline characteristics were well balanced between the two groups. IMNI significantly improved DFS (p < 0.001) in patients after PSM. IMNI was an independent prognostic factor for DFS.


In this study, we found that IMNI improved DFS and OS in breast cancer patients in the context of modern systemic treatment. These data continue to support that IMNI is a key component of RNI.


Breast cancer Internal mammary node irradiation Modern systemic treatment Survival outcome 



Axillary lymph nodes dissection


Breast cancer mortality


Breast-conserving surgery


Clinical target volumes


Disease-free survival


Deep inspiration breath hold


Electronic health records


Estrogen receptor


Fluorescence in situ hybridization


Human epidermal growth factor receptor 2


Hazard ratio




Internal mammary node irradiation


Locoregional recurrences


Mean heart dose


Neoadjuvant chemotherapy


Overall survival


Postmastectomy radiotherapy


Progesterone receptor


Propensity score matching


Regional nodal irradiation



This study was partly funded by the National Natural Science Foundation of China (Grant Number. 81602668).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

12282_2019_1015_MOESM1_ESM.docx (20 kb)
Supplementary file1 (DOCX 20 kb)


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Copyright information

© The Japanese Breast Cancer Society 2019

Authors and Affiliations

  1. 1.Department of Radiation OncologyFudan University Shanghai Cancer CenterShanghaiChina
  2. 2.Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
  3. 3.Department of Breast SurgeryFudan University Shanghai Cancer CenterShanghaiChina
  4. 4.Arthur G. James Cancer HospitalThe Ohio State UniversityColumbusUSA

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