Prognostic Impact of Adjuvant Radiotherapy in Breast Cancer Patients with One to Three Positive Axillary Lymph Nodes

Background: Radiotherapy, as an adjuvant treatment, plays a well-known role in prevention of locoregional recurrence in breast cancer patients. This study aims to investigate the impact of radiotherapy in patients with N۱ disease.Methods: In this retrospective study, we reviewed the characteristics and treatment outcomes of ۳۱۶ patients with a biopsy proven diagnosis of breast carcinoma and ۱-۳ positive axillary lymph nodes. The patients received treatment between ۱۹۹۵ and ۲۰۱۴. The patients had a median follow-up of ۶۰ (range: ۶-۱۸۲) months.Results: This study was conducted on ۳۱۶ patients with a median age of ۴۸ (range: ۲۶-۸۶) years. Among patients, ۲۱۵ underwent modified radical mastectomy and ۱۰۱ had breast-conserving surgery before adjuvant treatment. Indeed, ۲۵۹ patients received radiotherapy (radiation group) and ۵۷ did not (control group). There was locoregional recurrence in one control group patient and two patients in the radiation group. Multivariate analysis results indicated hormone receptor status as an independent prognostic factor for the ۵-year disease-free survival rate. Estrogen and progesterone receptor negativity (HR = ۱.۸۰, ۹۵% CI: ۱.۰۲-۳.۱۹, P=۰.۰۴۳) also had a negative influence on the ۵-year disease-free survival rate. However, radiotherapy had no significant effect on disease-free survival (P=۰.۴۴۶) and overall survival (P=۰.۰۵۸) rates.Conclusion: The results showed that adjuvant radiotherapy had no prognostic impacts on locoregional and distant disease control in breast cancer patients with N۱ disease.