# Post-Operative Radiation in Early Breast Cancer with N1 Disease: 10-Year Follow-Up

## TL;DR

A 10-year study found that post-operative radiation for early breast cancer with N1 disease did not improve survival for all patients, but helped those on hormonal therapy.

## Contribution

The study identifies a specific benefit of post-operative radiation in combination with hormonal therapy for post-menopausal breast cancer patients with N1 disease.

## Key findings

- Post-operative radiation did not significantly improve 10-year overall survival or disease-free survival in general.
- Patients on hormonal therapy who received radiation had significantly better 10-year overall survival.
- Unfavorable risk factors were more common in patients who received post-operative radiation.

## Abstract

Post-operative radiotherapy for post-menopausal women with early breast cancer and small-volume axillary lymph node involvement (N1 disease) is still controversial. The aim of our retrospective study is to assess the 10-year overall survival and disease-free survival of patients who received radiotherapy versus those who did not receive radiotherapy. We also aimed to evaluate factors that affected the use of radiotherapy. Our results revealed no significant differences in the 10-year overall survival and disease-free survival. There was, however, a significant improvement in 10-year overall survival in patients who had radiotherapy if hormonal therapy was received. Radiotherapy appears to be beneficial in improving overall survival in post-menopausal patients with N1 disease and early breast cancer, who are on hormonal therapy.

Post-operative radiotherapy for post-menopausal women with early breast cancer and N1 disease is controversial. Although locoregional control is improved, overall survival (OS) benefit is unclear. The clinical benefit of post-operative irradiation in this group of patients over 10 years was reviewed. We aimed to evaluate the OS, disease-free survival (DFS), and factors affecting OS and DFS. A retrospective review of 191 post-menopausal women with early breast cancer and N1 disease from 2004 to 2011 was performed. Demographics, post-operative histology, adjuvant treatment, OS, and DFS were evaluated. Post-operative radiation was given to 95 of 191 women (49.7%). Younger age at diagnosis (p < 0.001), a greater number of involved nodes (p = 0.004), lymphovascular invasion (LVI), and a higher tumor grade (p = 0.001) were more likely in women who received post-operative radiation. Nodal radiation did not improve 10-year DFS (p = 0.084) or OS (p = 0.203). Post-operative nodal radiation was associated with significant improvement in 10-year OS in women who received only hormonal therapy (p = 0.047) and no other systemic therapy. Women with unfavorable risk factors were more likely to receive post-operative radiation, likely due to a perceived higher risk of recurrence. Nodal radiation did not significantly improve 10-year DFS or OS in early breast cancer patients with N1 disease, and the benefit was not clearly demonstrated. However, in those who were on hormonal therapy, radiotherapy was beneficial in improving overall survival.